8 GHz 12-bit ADC Boasts 10.5 GSPS Sampling Rate

Texas Instruments (TI) has introduced a new ultra-high-speed ADC with what it claims is the industry’s widest bandwidth, fastest sampling rate and lowest power consumption. The ADC12DJ5200RF helps engineers achieve high measurement accuracy for 5G testing applications and oscilloscopes, and direct X-band sampling for radar applications, says TI. The company is demonstrating the ADC12DJ5200RF in booth No. 1272 at the International Microwave Symposium (IMS) in Boston this week (June 4-6).
The ADC12DJ5200RF’s 8 GHz bandwidth enables engineers to achieve as much as 20 percent higher analog input bandwidth than competing devices, which gives engineers the ability to directly digitize very high frequencies without the power consumption, cost and size of additional down-conversion. In dual-channel mode, the ADC12DJ5200RF samples at 5.2 GSPS and captures instantaneous bandwidth (IBW) as high as 2.6 GHz at 12-bit resolution. In single-channel mode, the new ultra-high-speed ADC samples at 10.4 GSPS and captures IBW up to 5.2 GHz.

As the first standalone GSPS ADC to support the JESD204C standard interface, according to TI, the ADC12DJ5200RF helps minimize the number of serializer/deserializer lanes needed to output data to field-programmable gate arrays (FPGAs), enabling designers to achieve higher data rates.

TI says the ADC12DJ5200RF has the highest available dynamic performance across power-supply variations, even at minimum specifications, which improves signal intelligence by providing ultra-high receiver sensitivity to detect even the smallest and weakest signals. In addition, the device includes internal dither which improves spurious-free performance.

High measurement accuracy means the device greatly minimizes system errors with offset error as low as ±300 µV and zero temperature drift. Engineers designing test and measurement equipment can achieve high measurement repeatability by taking advantage of the extremely low code error rate (CER) of the ADC12DJ5200RF, which is more than 100 times better than competing devices.

At 10 mm by 10 mm – 30 percent smaller than discrete solutions – the ADC12DJ5200RF helps engineers save board space. This ADC also requires a reduced number of lanes, which further allows for a smaller printed circuit board design. Engineers can minimize heat dissipation and simplify overall thermal management in their designs with the ADC12DJ5200RF 4-W power consumption, 20 percent lower than competitive ADCs.

The ADC12DJ5200RF is pin-compatible with the following other TI GSPS ADCs to provide an easy upgrade path from 2.7 GSPS to 10.4 GSPS, and minimizes the time and cost of redesign: ADC12DJ3200, ADC12DJ2700 and ADC08DJ3200. The ADC12DJ5200RF dual- and single-channel ultra-high-speed ADC is available for sampling through the TI store. The device is in a 144-ball, 10-by-10-mm flip-chip ball grid array (FCBGA) package.

Texas Instruments | www.ti.com

EOG-Controlled Video Game

Eyes as Interface

There’s much be to learned about how electronics can interact with biological signals—not only to record, but also to see how they can be used as inputs for control applications. With ongoing research in fields such as virtual reality and prosthetics, new systems are being developed to interpret different types of signals for practical applications. Learn how these three Cornell graduates use electrooculography (EOG) to control a simple video game by measuring eye movements.

By Eric Cole, Evan Mok and Alex Huang

The human eye naturally acts as a dipole, in which the retina at the back of the eye is negatively charged, and the cornea at the front of the eye is positively charged. EOG is a recording technique that measures this potential difference, and can be used to

Figure 1
Electrode placement for recording. An Ag-AgCl (silver-silver chloride) electrode was placed at each of the labeled points. Points A and B record the EOG signal for the right and left eyes, and point C provides a ground reference.

quantify eye movement [1]. A typical electrode placement pattern for EOG is shown in Figure 1. Each of the electrodes A and B records a voltage related to eye movement, and an electrode at point C serves as a ground reference.

When a user looks left, the cornea is close to electrode B and it records a positive voltage, while the retina is closer to electrode A, yielding a negative voltage. Similarly, looking right produces a negative voltage at B and a positive voltage at A. The difference between VB and VA relative to ground at C changes monotonically with gaze direction, and can be reliably used to model horizontal eye movement.

System Overview

The system we designed uses eye movements to play a video game on a display screen. Electrodes are placed on a player’s head to record only the horizontal EOG signal as shown in Figure 2. This signal is then filtered and amplified via an analog circuit and sent to an ADC on a Microchip Technology PIC32 microcontroller (MCU) (Figure 3). The PIC32 MCU stores the reading as a digital value and uses it to control a cursor on an LCD display screen. A program on the PIC32 continually displays obstacles that move across the screen, and the player moves his or her eyes to control the cursor and avoid obstacles.

Figure 2
Characterization of EOG signal. An example signal output is shown for a gain of approximately 885.

Figure 3
System overview. “Eye recording” is accomplished with the raw electrode signal.

This system is entirely powered without connection to an AC power source, instead using a 9 V battery to provide power for amplification and a chargeable power source to power the PIC32. This choice of a power source was important, because it enforces necessary safety considerations for biomedical recording. Connecting a high voltage source to a human user and accidentally completing a circuit path to AC ground could result in serious injury, so great care was taken to use battery power for this project.

A secondary oscilloscope program was also necessarily designed to satisfy a key safety need: The ability to view the recorded EOG signal and test the recording hardware while the circuit is isolated. A normal oscilloscope cannot be used for this purpose for the reasons stated earlier. Care was also taken to apply and fasten the electrodes properly before every session.

Recording and Application

Three Ag-AgCl (silver-silver chloride) electrodes are placed around the eyes using a skin-safe adhesive gel—one beside each eye, and one on the forehead as a ground reference—at points A, B, and C respectively, in Figure 1. These electrodes provide the gateway between the biological signal and the digital world, detecting the voltage generated by ions at the skin surface and transducing it into an equivalent electron-based signal.

This voltage is generated directly at the eye, and has some attenuation through the skin surface. A typical magnitude of the raw EOG signal is several millivolts. The voltage readings from the two eye electrodes are sent to a Texas Instruments (TI) INA121 differential amplifier, which amplifies the difference between the two input signals. This yields a negative or positive voltage based on direction of eye movement. The INA121 provides low noise, a high common-mode rejection ratio, and is suitable for the high-input impedance requirement associated with recording biological signals. Figure 4 shows the full schematic of the implementation.

A second amplification stage using a TI LM358-based balanced subtractor configuration provides further amplification. This stage reduces the DC voltage component output from the differential amplifier, while further amplifying the difference to a range of 0 to 3.3 V—the scale allowed by the PIC32 MCU’s on-chip ADC. The resulting signal is a voltage centered at approximately 1.6 V when the user looks straight, with about a 1 V increase or decrease when the user looks left or right, respectively. …

Read the full article in the July 348 issue of Circuit Cellar
(Full article word count: 3023 words; Figure count: 6 Figures.)

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Software/Hardware Solution Facilitates IoT System Development

Recon Industrial Controls has announced LabRecon, a software and hardware product that enables users to create rich graphical interfaces for “remote” IoT or “local” measurement and control applications. A drag-and-drop panel builder and graphical programming environment allows one to easily build an interface and create the operating logic for any project. A USB connected “Breadboard Experimentor” circuit board provides the measurement and control link.
The product features a “Measurement Wizard” that lets you choose from a built-in database of over 500 commercially available sensors to automatically configure sensor configurations. The wizard also provides circuits with component values for voltage and current measurements. LabRecon’s “Breadboard Experimentor” incorporates a solder-less breadboard to quickly build interface circuitry to sensors or output devices. The on-board LabRecon chip provides many I/O options including 8 12-bit analog, frequency and digital inputs. Outputs comprise PWM, servo, frequency and stepper motor signals. Pins can also be configured to support 24-bit ADCs, 12 or 16-bit DACs and port expanders. As an alternative to the Breadboard Experimentor, LabRecon chips are available in DIP packages, which provide the same I/O functionality.

The software’s graphical programming feature uses Drag-and-drop functions, which can be wired together, to add analysis and control functionality to a project. Algorithms can be further expanded using the “code link” interface to text-based languages such as Python, Java, C#, Visual Basic and so on. LabRecon also comprises a server to allow access of the created GUI by computers or mobile devices. Furthermore, emails and text messages can be sent periodically or upon events. The server also includes a MQTT broker to allow MQTT clients to share data with the software. Even without Breadboard Experimentor or the LabRecon chip, the software has powerful features that can be used for free. Such features include simulation, the Measurement Wizard and a serial monitor/terminal.

A Kickstarter campaign is underway for the LebRecon product. The Kickstarter link is posted on www.LabRecon.com

Recon Industrial Controls | www.labrecon.com

 

Tailored Solutions Tackle Design Needs for Wearables

Low Power Priorities

For wearable devices, every drop of power is precious. That’s driving designers of these embedded systems to attack the power challenge from multiple angles. Fortunately, a slew of analog, power and system ICs have emerged that address the wearable market’s particular needs.

By Jeff Child, Editor-in-Chief

While power is an important issue in any embedded system design, it’s especially critical in wearable devices. Today’s generation of wearable electronics require longer battery lives, more functionality and better performance—all in extremely small form factors. Wearables comprise a wide variety of products including smartwatches, physical activity monitors, heart rate monitors, smart headphones and more.
Today’s wearable electronic devices share some common design priorities. First, they have an extremely low budget for power consumption. And because they’re not suited to being powered by replaceable batteries, they usually require a way for the unit to be recharged. Meanwhile, most modern wearables require some kind of wireless connectivity.

Feeding those needs, chip vendors—primarily from the microcontroller (MCU) and analog sectors—over the past 12 months have announced a generous mix of solutions to help keep power consumption low, to aid recharging and to enable new capabilities while maintaining narrow power constraints. Chip and platform solutions aimed at wearables span the range from specialized power management ICs (PMICs), data converters and power regulator chips, to wireless charging solutions and even complete reference design platforms specially for wearables.

Wrist-Worn Health Gear

Wearables have evolved from being more than just fun devices for health and fitness. Using sophisticated sensors and other capabilities, devices are being designed to do virtual care monitoring, assess chronic conditions and evaluate overall well-being. Along just those lines, in September Maxim Integrated announced its Health Sensor Platform 2.0 (HSP 2.0) (Figure 1). This wrist-worn platform can be used for rapid prototyping, evaluation and development. It provides the ability to monitor electrocardiogram (ECG), heart rate and body temperature from a wrist-worn wearable, saving up to six months in development time, according to Maxim.

Figure 1
The Health Sensor Platform 2.0 is a wrist-worn platform that can be used for rapid prototyping, evaluation and development. It provides the ability to monitor electrocardiogram (ECG), heart rate and body temperature from a wrist-worn wearable.

In the past, system developers have found it challenging to derive precise ECG monitoring from the wrist—most alternatives require a wearable chest strap. Getting accurate body temperature typically requires using a thermometer at another location. Maxim has overcome these challenges in the HSP 2.0. by using its proprietary sensor and health monitoring technology.

Enclosed in a watch casing, the wrist-based form factor enables HSP 2.0 to provide basic functionality out of the box, with body-monitoring measurements starting immediately. Data can be stored on the platform for patient evaluation or streamed to a PC for analysis later. Unlike other wearables, the data measurements collected by the HSP 2.0 can be owned by the wearer. This alleviates data privacy concerns and enables users to conduct their own data analysis. Also, because HSP 2.0 is an open platform, designers can evaluate their own algorithms on the board. In addition, the modular format is future proof to quickly accommodate new sensors over time.

HSP 2.0 includes the following Maxim chips: the MAX32630 DARWIN low-power MCU for wearables; the MAX32664 ultra-low-power biometric sensor hub with embedded heart-rate algorithm; the MAX20303 PMIC; the MAX30205 human body temperature sensor with ±0.1°C accuracy; the MAX30001 single-channel integrated biopotential and bioimpedance analog front-end (AFE) solution; and the MAX86141 optical pulse oximeter and heart-rate sensor.

Energy Controller for Wearables

For its part, Renesas Electronics has been working on meeting extreme low power demands by applying innovations in semiconductor process development. In November the company unveiled an innovative energy-harvesting embedded controller that can eliminate the need to use or replace batteries in a device. Developed based on Renesas’ SOTB (silicon-on-thin-buried-oxide) process technology, the new embedded controller achieves extreme reduction in both active and standby current consumption. The extreme low current levels of the SOTB-based embedded controller enables system designers to completely eliminate the need for batteries in some of their products through harvesting ambient energy sources such as light, vibration and flow (Figure 2).

Figure 2
The extreme low current levels of the SOTB-based embedded controller enables system designers to completely eliminate the need for batteries in some of their products through harvesting ambient energy sources such as light, vibration and flow.

Although the solution was developed with IoT devices in mind, the controller is more broadly aimed at what they call the new market of maintenance-free, connected IoT sensing devices with endpoint intelligence. This includes health and fitness apparel, shoes, wearables, smart watches and drones. Renesas’ first commercial product using SOTB technology, the R7F0E embedded controller, is a 32-bit, Arm Cortex-based embedded controller. The device is capable of operating up to 64 MHz for rapid local processing of sensor data and execution of complex analysis and control functions.

The R7F0E consumes just 20 μA/MHz active current, and only 150 nA deep standby current, approximately one-tenth that of conventional low-power MCUs. According to the company, samples of the new R7F0E embedded controller are available now for beta customers, and samples are scheduled to be available for general customers from July 2019. Mass production is scheduled to start from October 2019.

LDO Regulator for Wearables

Achieving longer battery lives is a problem that can be attacked from many angles. Power regulator electronics are among those. With that in mind, Microchip Technology in October introduced a linear Low Dropout (LDO) regulator that extends battery life in portable devices up to four times longer than traditional ultra-low quiescent (IQ) LDOs. With an ultra-low IQ of 250 nA versus the approximately 1 µA operation of traditional devices, the MCP1811 LDO reduces quiescent current to save battery life, enabling end users to recharge or replace batteries less often (Figure 3).

Figure 3
With an ultra-low IQ of 250 nA versus the approximately 1 µA operation of traditional devices, the MCP1811 LDO regulator saves battery life, enabling end users to recharge or replace batteries less often.

Well suited for IoT and battery-operated applications such as wearables, remotes and hearing aids, the LDO reduces power consumption in applications by minimizing standby or shutdown current. Reducing standby power consumption is critical in remote, battery-powered sensor nodes, where battery replacement is difficult and operating life requirements are high. Available in package options as small as 1 mm x 1 mm, the MCP1811 consumes minimal board space to meet the needs of today’s compact portable electronic designs. Depending on the application and number of LDOs, designers can take advantage of the extra board space with a larger battery to further increase battery life.

An additional benefit the MCP1811 offers is faster load line and transient response when compared to other ultra-low IQ LDOs. Faster response times can accelerate wake-up speed in devices such as monitors or sensors that require immediate attention. Faster transient response can help designers avoid undervoltage and overvoltage lockout measures used in sensitive applications where transient spikes can lead to catastrophic results.

Secure Payments with Wearables

An important capability in a certain class of wearables is the ability to support electronic retail transactions directly from the wearable device. While this is arguably a whole separate technology category in itself, we’ll touch on a couple developments here. In November, Infineon Technologies announced an EMV-based payment solution for key chains, rings, wristbands, bracelets and other wearable devices.

The SECORA Pay W for Smart Payment Accessories (SPA) combines an EMV chip with the card operating system, payment applet as well as the antenna directly on the unit. As a turnkey solution it allows card vendors, device manufacturers, financial institutions or event organizers to quickly and cost-efficiently introduce fashion accessories for payment and even access.

Infineon’s SECORA Pay solutions portfolio comprises the SECORA Pay S for standard Visa and MasterCard payment cards, SECORA Pay X for applications with extended features such as multi-application, national debit and white label schemes or access management and SECORA Pay W for payment accessories. All SECORA turn-key solutions are pre-certified by Mastercard and Visa and will accelerate the deployment of contactless payment. The EMV Chip Specifications (www.emvco.com) define globally valid requirements for chip-based payment solutions and acceptance terminals. They enable secure contact- and contactless applications and the use of other emerging payment technologies.

Complete Payment SoC

Likewise a player in the contactless transaction market, STMicroelectronics (ST) back in October announced teaming up with Fidesmo to create a turnkey active solution for secure contactless payments on smart watches and other wearable technology. The complete payment system-on-chip (SoC) is based on ST’s STPay-Boost IC, which combines a hardware secure element to protect transactions and a contactless controller featuring proprietary active-boost technology that maintains reliable NFC connections even in devices made with metallic materials. Its single-chip footprint fits easily within wearable form factors (Figure 4).

Figure 4
The STPay-Boost IC combines a hardware secure element to protect transactions and a contactless controller featuring proprietary active-boost technology that maintains reliable NFC connections even in devices made with metallic materials. Its single-chip footprint fits easily within wearable form factors.

ST’s proprietary NFC-boosting active load modulation technology simplifies RF design and accelerates time to market by ensuring superior performance with little or no circuit optimization needed. A small-size antenna can sustain robust and reliable wireless connection, permitting smaller overall product dimensions and lower power consumption resulting in longer battery life.

Fidesmo’s MasterCard MDES tokenization platform completes the solution by allowing the user to load the personal data needed for payment transactions. Convenient Over-The-Air (OTA) technology makes personalization a simple step for the user without any special equipment. Kronaby, a Sweden-based hybrid smartwatch maker, has embedded the STPay-Boost chip in its portfolio of men’s and women’s smart watches that offer differentiated features such as freedom from charging and filtered notifications. The SoC with Fidesmo tokenization enables Kronaby watches to support a variety of services such as payments, access control, transportation and loyalty rewards.

Data Converters

Data converters also have role to play in efforts to meet the extreme low power needs of wearable devices. Along such lines, in December Texas Instruments (TI) introduced four tiny precision data converters (Figure 5). The new data converters enable designers to add more intelligence and functionality, while shrinking system board space. The DAC80508 and DAC70508 are eight-channel precision digital-to-analog converters (DACs) that provide true 16- and 14-bit resolution, respectively.

Figure 5
The DAC80508 and DAC70508 are eight-channel precision DACs that provide true 16- and 14-bit resolution, respectively. The ADS122C04 and ADS122U04 are 24-bit precision ADCs that feature a two-wire, I2C-compatible interface and a two-wire, UART-compatible interface, respectively.

The ADS122C04 and ADS122U04 are 24-bit precision analog-to-digital converters (ADCs) that feature a two-wire, I2C-compatible interface and a two-wire, UART-compatible interface, respectively. The devices are optimized for a variety of small-size, high-performance or cost-sensitive electronics applications such as wearables.

Both DACs include a 2.5-V, 5-ppm/°C internal reference, eliminating the need for an external precision reference. Available in a 2.4-mm-by-2.4-mm die-size ball-grid array (DSBGA) package or wafer chip-scale package (WCSP) and a 3-mm-by-3-mm quad flat no-lead (QFN)-16 package, these devices are up to 36% smaller than the competition, says TI. Meanwhile, the tiny, 24-bit precision ADCs are available in 3-mm-by-3-mm very thin QFN (WQFN)-16 and 5-mm-by-4.4-mm thin-shrink small-outline package (TSSOP)-16 options. The two-wire interface requires fewer digital isolation channels than a standard serial peripheral interface (SPI), reducing the overall cost of an isolated system. These precision ADCs eliminate the need for external circuitry by integrating a flexible input multiplexer, a low-noise programmable gain amplifier and other circuitry.

Memory Innovations

Among the latest innovations aimed at wearables from Cypress Semiconductor is an FRAM (ferroelectric random access memory)-based data logging solution. In November, Cypress introduced a nonvolatile data-logging solution with ultra-low power consumption. This solution is well suited for portable medical and wearable devices that demand nonvolatile memories to continuously log an increasing amount of user and sensor data while using as little power as possible.

Cypress’ Excelon LP FRAM is an energy-efficient device that provides instant-write capabilities with virtually unlimited endurance (Figure 6). This enables wearable systems to perform mission-critical data logging requirements while maximizing battery life. The Excelon LP series is available in a low-pin-count, small-footprint package that is suited for space-constrained, wearable applications.

Figure 6
The Excelon LP FRAM provides instant-write capabilities with virtually unlimited endurance. This enables wearable systems to perform mission-critical data logging requirements while maximizing battery life.

The Excelon LP series offers 4-Mb and 8-Mb industrial and commercial-grade densities with 50 MHz and 20 MHz Serial Peripheral Interface (SPI) performance. The series reduces power consumption with 100 nA hibernate and 1 µA standby modes that greatly improve a battery-powered product’s user experience by extending system operating time. The device’s inherent instant writes also eliminate power failure “data-at-risk” due to volatile data buffers in legacy memories. The family features wide voltage operation from 1.71 V to 3.6 V and is available in RoHS-compliant industry-standard packages that are pin compatible with EEPROMs and other nonvolatile memories. Excelon LP F-RAMs provide 1,000-trillion (1015) read/write cycle endurance with 10 years of data retention at 85°C or 151 years at 65°C.

Charging Wearables

A common aspect of wearable devices is that they tend not to be suited for replaceable batteries. As a result, they typically need to be recharged. Wireless (cordless) battery charging is beginning to take hold as a solution. Feeding such needs, in October Analog Devices announced its Power by Linear LTC4126 as an expansion of its offerings in wireless battery charging. The LTC4126 combines a wireless powered battery charger for Li-Ion cells with a high efficiency multi-mode charge pump DC-DC converter, providing a regulated 1.2 V output at up to 60 mA (Figure 7).

Figure 7
The LTC4126 combines a wireless powered battery charger for Li-Ion cells with a high efficiency multi-mode charge pump DC-DC converter, providing a regulated 1.2 V output at up to 60 mA.

Charging with the LTC4126 allows for a completely sealed end product without wires or connectors and eliminates the need to constantly replace non-rechargeable (primary) batteries. The efficient 1.2 V charge pump output features pushbutton on/off control and can directly power the end product’s ASIC. This greatly simplifies the system solution and reduces the number of necessary external components. The device is ideal for space-constrained low power Li-Ion cell powered wearables such as hearing aids, medical smart patches, wireless headsets and IoT devices.

The LTC4126, with its input power management circuitry, rectifies AC power from a wireless power receiver coil and generates a 2.7 V to 5.5 V input rail to power a full-featured constant-current/constant-voltage battery charger. Features of the battery charger include a pin selectable charge voltage of 4.2 V or 4.35 V, 7.5 mA charge current, automatic recharge, battery temperature monitoring via an NTC pin, and an onboard 6-hour safety charge termination timer. Low battery protection disconnects the battery from all loads when the battery voltage is below 3.0 V. The LTC4126’s charge pump switching frequency is set to 50 kHz/75 kHz to keep switching noise out of the audible range, ideal for audio related applications such as hearing aids and wireless headsets. The IC is housed in a compact, low profile (0.74 mm) 12-lead 2 mm × 2 mm LQFN package. The device is guaranteed for operation from –20°C to 85°C in E-grade.

Kit for Wireless Charging

Also facilitating building wireless chargers for wearables, ST for its part offers a kit-level solution. The ST plug-and-play wireless battery-charger development kit (STEVAL-ISB045V1) lets users quickly build ultra-compact chargers up to 2.5 W with a space-saving 20 mm-diameter coil, for charging small IoT devices and wearables such as smart watches, sports gear or healthcare equipment (Figure 8).

Figure 8
The ST plug-and-play wireless battery-charger development kit lets users quickly build ultra-compact chargers up to 2.5 W with a space-saving 20 mm-diameter coil, for charging small IoT devices and wearables such as smart watches, sports gear or healthcare equipment.

Built around the STWBC-WA wireless charging-transmitter controller, the kit comprises a charging base unit containing a transmitter board with the 20 mm coil already connected and ready to use. Getting started is easy, using the PC-based STSW-STWBCGUI software to configure the STWBC-WA and monitor runtime information such as power delivered, bridge frequency, demodulation quality and protocol status. The kit includes a dongle for running the GUI. The supporting ecosystem includes certified reference boards, software and detailed documentation to help developers quickly design chargers for wearables.

The STWBC-WA controller chip contains integrated drivers and natively supports full-bridge or half-bridge topologies for powering the antenna. The half-bridge option allows charging up to 1 W with a smaller-diameter coil for an even more compact form factor. The chip supports all standard wireless-charging features, including Foreign Object Detection (FOD) and active presence detection for safe charging, and uses digital feedback to adapt the transmitted power for optimum efficiency at all load conditions. Two firmware options give users the choice of a fast turnkey solution or customizing the application using APIs to access on-chip peripherals including an ADC, a UART and GPIOs.

Clearly there are many facets and angles to address the low power needs of wearables. As demands for more functionality rise, system developers will need to remain ever mindful of keeping battery life at the same lengths or longer. Fortunately, there seems to be no stopping the innovation among chip vendors targeting this growing wearables market.

RESOURCES

Analog Devices | www.analog.com
Cypress Semiconductor | www.cypress.com
Infineon Technologies | www.infineon.com
Maxim Integrated | www.maximintegrated.com
Microchip Technology | www.microchip.com
Renesas Electronics America | www.renesas.com
STMicroelectronics | www.st.com
Texas Instruments | www.ti.com

This article appeared in the March 344 issue of Circuit Cellar

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Pitfalls of Filtering Pulsed Signals

Waveform Woes

Filtering pulsed signals can be a tricky prospect. Using a recent customer problem as an example, Robert highlights various alternative approaches and describes the key concepts involved. Simulation results are provided to help readers understand what’s going on.

By Robert Lacoste

Welcome back to the Darker Side. A couple of months ago, one of our customers was having trouble with its project and called us for help. As is often the case, the problem was more a misunderstanding of the underlying concepts than any kind of hardware or software issues. We helped him, but because the same issue could jeopardize your own projects I thought it would be a nice topic for this column.

The Project

What is it about? Of course, I won’t be able share the details of our customer’s project, but I will describe a close example. Let’s imagine you need to build an ultrasonic ranging system. Just as bats do, you want to transmit short bursts of ultrasound, then listen for echoes. As you probably know, the time between transmission and reception divided by twice the speed of sound will give you the distance of the obstacle.

Moreover, the shift in frequency between transmitted and received bursts will give you the relative speed of this obstacle, thanks to the so-called Doppler shift. Ok, but how will you design such a ranging device? First, you’ll need to generate and transmit bursts of sine waves—also called tone bursts—with the proper ultrasonic frequency, say 40 kHz. That’s easy to do even with a pair of trusty NE555 chips or NAND gates, or maybe with a microcontroller if you prefer dealing code rather than a soldering iron. These bursts will need to be as short as possible—maybe 1 ms or so—because this will improve the distance resolution.

The transmit side is easy, but the receiver will be a little more complex. In real life, the received signal will have a very low amplitude and probably plenty of added noise. This is especially true if you consider that the Doppler shift could be significant, meaning with fast-moving objects. In that case you will not know the exact frequency of the burst you should detect.

Figure 1
Shown here is a basic ultrasonic meter. A narrow band-pass filter, tuned to the received frequency, allows you to reduce perturbations and noise. But does this work?

One possible architecture to avoid this problem, while minimizing noise, could be the one illustrated on Figure 1. First, do a spectrum analysis of the received signal. Because this signal contains noise plus the received ultrasonic echo, its frequency spectrum will show a peak at the frequency of the received ultrasonic carrier. Therefore, you can measure this actual reception frequency. Assume it is 40.5 kHz due to Doppler shift. You can use this information to tune a very selective band-pass filter, which will isolate the received ultrasonic burst from any other noise. Why not a 40.5 kHz +/-100 Hz filter? You will then recover a clean version of the received pulse and measure the time difference between transmission and reception with a detector and a time counter. Brilliant idea, isn’t it? If you agree, then please read on. This was the concept used by our customer, and unfortunately it doesn’t work! At least not as described. In this article I will explain why, using some easy to understand simulations and as little math as possible. So, don’t’ be afraid. Come with me to the Darker Side of pulsed signals.

Digital Version

Before going into the explanation, I need to present you an alternative version of this intended receiver. Because you are a reader of Circuit Cellar, you know that developing such a design would be far easier using digital signal processing than trying to build analog spectrum analyzers and precisely tuned filters. The digital equivalent of this receiver is illustrated on Figure 2. Just compare it with the former, you will find the same concepts.

Figure 2
Here’s a digital version of the same concept shown in Figure 1. All the yellow functions can be executed on a digital processor (fast microcontroller, digital signal processor, FPGA or anything else).

Here the received signal is preamplified and directly digitized with a properly selected analog-to-digital converter (ADC). Its frequency spectrum can then be calculated with a Fourier Transform, using the well-known Fast Fourier Transform (FFT) algorithm, for example. The frequency peak can then be searched into this spectrum. Then a narrow band-pass filter can be created and tuned to this frequency and the filtered signal can be calculated. …

Read the full article in the August 337 issue of Circuit Cellar

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MCUs Eye Closed-Loop Control Applications

Microchip Technology has introduced the new PIC18 Q10 and ATtiny1607 families, featuring multiple intelligent Core Independent Peripherals (CIPs) that simplify development and enable quick response time to system events. Advancements in the architecture of PIC and AVR 8-bit microcontrollers (MCUs) have optimized the devices for implementing closed-loop control, enabling systems to offload the Central Processing Unit (CPU) to manage more tasks and save power.

Well suited for applications that use closed-loop control, a key advantage of using the PIC18 Q10 and ATtiny1607 MCUs are the CIPs that independently manage tasks and reduce the amount of processing required from the CPU. System designers can also save time and simplify design efforts with the hardware-based CIPs, which significantly reduce the amount of software required to write and validate. Both families have features for functional safety and operate up to 5 V, increasing noise immunity and providing compatibility with the majority of analog output and digital sensors.

Offered in a compact 3 mm x 3 mm 20-pin QFN package, the new ATtiny1607 family is optimized for space-constrained closed-loop control systems such as handheld power tools and remote controls. In addition to the integrated high-speed Analog-to-Digital Converter (ADC) that provides faster conversion of analog signals resulting in deterministic system response, the devices provide improved oscillator accuracy, allowing designers to reduce external components and save costs.

Among CIPs in the PIC18 Q10 family are the Complementary Waveform Generator (CWG) peripheral, which simplifies complex switching designs, and an integrated Analog-to-Digital Converter with Computation (ADC2) that performs advanced calculations and filtering of data in hardware without any intervention from the core. CIPs such as these allow the CPU to execute more complex tasks, such as Human Machine Interface (HMI) controls, and remain in a low-power mode to conserve power until processing is required.

All PIC18 Q10 products are supported by MPLAB Code Configurator (MCC), a free software plug-in that provides a graphical interface to easily configure peripherals and functions. MCC is incorporated into Microchip’s downloadable MPLAB X Integrated Development Environment (IDE) and the cloud-based MPLAB Xpress IDE, eliminating the need to download software. The Curiosity High Pin Count (HPC) development board (DM164136), a fully-integrated, feature-rich rapid prototyping board, can also be used to start development with these MCUs.

Rapid prototyping with the ATtiny1607 family is supported by ATmega4809 Xplained Pro (ATmega4809-XPRO) evaluation kit. The USB-powered kit features touch buttons, LEDs and extension headers for quick setup as well as an on-board programmer/debugger that seamlessly integrates with the Atmel Studio 7 Integrated Development Environment (IDE) and Atmel START, a free online tool to configure peripherals and software that accelerates development.

The PIC18 Q10 and ATtiny1607 are available today for sampling and in volume production. Pricing for the PIC18 Q10 family starts at $0.77 each in 10,000-unit quantities, and pricing for the ATtiny1607 family starts at $0.56 each in 10,000-unit quantities.

Microchip Technology | www.microchip.com

MCU-Based Blood Pressure Monitoring Eval Kit

Renesas Electronics has announced an expansion of its healthcare solution lineup with the launch of a new blood pressure monitoring evaluation kit. The new blood pressure monitoring evaluation kit comprises hardware and software elements needed to jump start blood pressure measurement design. The kit includes a pressure sensor, arm cuff, pump, electronically controlled valve, LCD panel and a reference board. The reference board incorporates an RL78 MCU-based ASSP (application specific standard product) that includes analog functions required for blood pressure measurement. Reference software and graphical user interface (GUI) development tool are also part of the new evaluation kit. Using the new evaluation kit, system manufacturers can immediately begin their system evaluations and significantly reduce their development time.


The Internet of Things offers consumers connected tools with which to manage their personal healthcare more efficiently. For instance, blood pressure monitors are already popular personal medical devices and the market is expected to grow further as blood pressure monitoring functions are incorporated into wearable devices. The growth of this market offers new business opportunities, but can also be challenging, particularly for system manufacturers who are new to the connected healthcare device ecosystem and may not have the built-in application-specific expertise. Blood pressure measurement requires a specific expertise, including filtering functions for extracting the waveforms required for measurement, making it extremely time consuming to start studying this area from the very beginning.

Renesas has developed the new blood pressure monitoring evaluation kit to alleviate the development pain points, providing functions close to those used in actual blood pressure monitors thus accelerating blood pressure measurement system development.

Key features of the blood pressure monitoring evaluation kit:

The new blood pressure monitoring evaluation kit comprises hardware and software elements needed to jump start blood pressure measurement design, including:

  • A full range of hardware components, including a pressure sensor, arm cuff, pump, electronically controlled valve, LCD panel, and a reference board that incorporates the newly-developed RL78/H1D ASSP with the analog functions required for blood pressure measurement.
  • Reference software that provides the algorithms required for blood pressure measurement and that can be easily modified, as well as access to smartphone applications, and a graphical user interface (GUI) tool.
  • A Bluetooth Low Energy (BLE) module, which enables the measured data to be transmitted to a smartphone under the Continua standard blood pressure monitoring (BPM) profile is also provided in the new evaluation kit.

Development support with GUI tool, specialized for blood pressure measurement

  • The pressure sensor, pump, electronically controlled valve components, and pulse width modulation control can be set from the GUI tool. If the system structure is the same, the GUI tool can also be used for system evaluation of the actual application the system manufacturer is developing.
  • The IIR digital filter calculations required for extracting the pulse waveform from the cuff pressure output waveform during blood pressure measurement can also be simulated using the GUI tool. The digital filter constants calculated based on this simulation can be written from the GUI tool to the RL78/H1D firmware and verified in the actual application being developed. This significantly reduces the number of steps in the development process.

RL78/H1D ASSP with optimized analog functions for healthcare applications

  • The RL78/H1D is a new ASSP of the RL78 Family of MCU. The RL78/H1D, designed to control systems required for blood pressure measurement with a single chip. It incorporates rich analog functions including high-resolution delta sigma A/D converters, programmable gain instrumentation amplifiers, D/A converters, operational amplifiers, and other circuits required for blood pressure measurement, as well as timers for PWM (pulse-width modulation) control.
  • In addition to the delta sigma 24-bit A/D converters, the RL78/H1D also provides 10-bit sequential comparison A/D converters that operate asynchronously. This simplifies implementation of systems providing temperature measurement and battery voltage monitoring while measuring the blood pressure.
  • The Rich analog functions make the new ASSP ideal not only for blood pressure monitoring systems but also for a wide array healthcare application including biosensors.
  • Samples of the RL78/H1D ASSP are available now. Pricing varies depending on the memory capacity, package and number of pins. For example, the R5F11NMG 80-pin LQFP package type with 128 KB flash ROM capacity is priced at US$3.50. The R5F11NMG includes an LCD controller for arm- and wrist-type blood pressure monitors, and a 4mm x 4 mm miniature ball grid array (BGA) package for use in wearable devices.

Renesas plans to expand its range of solutions for the healthcare field and will continue to contribute to the realization of a safe and secure smart society, including the development of smart connected devices for the industrial and healthcare industries.

 

The new blood pressure monitoring evaluation kit is scheduled to be available for order from May 10 priced at $600 per unit.

Renesas Electronics | www.renesas.com

Gesture Recognition in a Boxing Glove

Sensors Packed in the Punch

Learn how these two Boston University graduate students built a gesture-detection wearable that acts as a building block for a larger fitness telemetry system. Using a Linux-based Gumstix Verdex, the wearable couples an inertial measurement unit with a pressure sensor embedded in a boxing glove.

By Blade Olson and Patrick Dillon

Diagnostic monitoring of physical activity is growing in demand for physical therapists, entertainment technologists, sports trainers and for postoperative monitoring with surgeons [1][2]. In response to the need for a low-cost, low-profile, versatile, extensible, wearable activity sensor, the Hit-Rec boxing sensor is a proof-of-concept device that demonstrates on-board gesture recognition and high-throughput data monitoring are possible on a wearable sensor that can withstand violent impacts. The Hit-Rec’s ability to gather raw sensor values and run calculations at a high frame rate make the Hit-Rec an ideal diagnostic device for physical therapists searching for slight perturbations across a user’s gestures in a single recording session or for looking at discrepancies between the ideal motions of a healthy individual and the user’s current motions. The following sections will describe the implementation of a prototype for the Hit-Rec using a boxing glove (See Lead Photo Above).

SYSTEM OVERVIEW

The Hit-Rec sensor incorporates a Gumstix Verdex Pro running Linux, a 9-DoF (degree of freedom) inertial measurement unit (IMU), a pressure sensor that is connected to the Gumstix via a 12-bit analog-to-digital converter (ADC) and LEDs for user feedback. The ADC and IMU both communicate over I2C. The LEDs communicate to the Gumstix through general purpose input/output (GPIO). Figure 1 shows a high-level explanation of hardware interfaces and Figure 2 provides an illustration of the system overview. All software was written in C and runs exclusively on the Gumstix Verdex Pro. A Linux kernel module was written to interact with the LEDs from the user-space program that performs data capture and analysis. IMU data was smoothed and corrected in real-time with an open-source attitude and heading reference system (AHRS) provided by Mahony [3][4]. A circular buffer queue was used to store and retrieve sensor data for recording and analysis. Punch classification compares accelerometer values at each data point and chooses the gesture with smallest discrepancy.

Figure 1
This high-level diagram details the data transfer connections made between the main hardware and software components of the Hit-Rec.

Figure 2
Overview of the software architecture for translating IMU and Pressure data to user feedback

Each of three LEDs on the Hit-Rec glove represents a different gesture type. After the “punchomatic” program is started, the user is prompted to record three gestures by way of three flashing LEDs. In the background, IMU data is continuously being recorded. The first, yellow LED flashes until an impact is registered, at which point the last 50 frames of IMU data are used as the “fingerprint“ for the gesture. This gesture fingerprint is stored for the rest of the session. Two additional gestures are recorded in an identical manner using the red and blue LEDs for the subsequent punches. After three gestures have been recorded, the user can punch in any form and the Hit-Rec will classify the new punch according to the three recently recorded punch gestures. Feedback on the most closely related punch is presented by lighting up the corresponding LED of the originally recorded gesture when a new punch occurs.

SENSORS

We used the Adafruit LSM9DS0 with breakout board as an IMU sensor and a force-sensitive resistor (FSR) from Adafruit as a pressure sensor. Both sensors communicate over I2C, which the pressure sensor achieves through an ADC. …

Read the full article in the June 335 issue of Circuit Cellar

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Wide Range Power Monitor Embeds ADCs

Analog Devices, acquired earlier this year by Linear Technology, has announced the LTC2992, a wide range I²C system monitor that monitors the current, voltage and power of two 0 V to 100 V rails without additional circuitry. The LTC2992 has flexible power supply options, deriving power from a 3 V to 100 V  monitored supply, a 2.7 V to 100 V secondary supply, or from the on-board shunt regulator. These supply options eliminate the need for a separate buck regulator, shunt regulator or inefficient resistive divider while monitoring any 0 V to 100 V rail. The LTC2992 is a simple, single-IC solution that uses three delta-sigma ADCs and a multiplier to provide 8- or 12-bit current and voltage measurements and 24-bit power readings.

LTC2992The LTC2992’s wide operating range is ideal for many applications, especially 48V telecom equipment, advanced mezzanine cards (AMC) and blade servers. The onboard shunt regulator provides support for supplies greater than 100V and negative supply monitoring. The LTC2992 measures current and voltage either continuously or on-demand, calculates power and stores all of this information along with minimum and maximum values in I²C accessible registers. Four GPIOs can also be configured as ADC inputs to measure neighboring auxiliary voltages. Measurements are made with only ±0.3% of total unadjusted error (TUE) over the entire temperature range. If any parameter trips the user-programmable thresholds, the LTC2992 flags an alert register and pin per the SMBus alert response protocol. The 400 kHz I²C interface features nine device addresses, a stuck bus reset timer, and a split SDA pin that simplifies I²C opto-isolation.  The LTC2992-1 version offers an inverted data output I²C pin for use with inverting opto-isolator configurations.

The LTC2992 and LTC2992-1 are offered in commercial, industrial and automotive versions, supporting operating temperature ranges from 0°C to 70°C, –40°C to 85°C and –40°C to 125°C, respectively. Both versions are available today in RoHS-compliant, 16-lead 4mm x 3mm DFN and 16-lead MSOP packages. Pricing starts at $3.85 each in 1,000-piece quantities. Please visit www.linear.com/products/power_monitors for more product selection and information.

Summary of Features:

  • Rail-to-Rail Input Range: 0 V to 100 V
  • Wide Input Supply Range: 2.7 V to 100 V
  • Shunt Regulator for Supplies >100 V
  • Three Delta-Sigma ADCs with Less Than ±0.3% TUE
  • 12-Bit Resolution for Currents & Voltages
  • Four GPIOs Configurable as ADC Inputs
  • Shutdown Mode with IQ < 50 µA
  • I²C Interface
  • Split SDA Pin Eases Opto-Isolation
  • Available in 16-Lead 4mm x 3mm DFN & 16-Lead MSOP Packages

Analog Devices | www.analog.com

Linear Technology | www.linear.com

Sensor Node Gets LoRaWAN Certification

Advantech offers its standardized M2.COM IoT LoRaWAN certified sensor node WISE-1510 with integrated ARM Cortex-M4 processor and LoRa transceiver. The module the  is able to provide multi-interfaces for sensors and I/O control such as UART, I2C, SPI, GPIO, PWM and ADC. The WISE-1510 sensor node is well suited for for smart cities, WISE-1510_3D _S20170602171747agriculture, metering, street lighting and environment monitoring. With power consumption optimization and wide area reception, LoRa  sensors or applications with low data rate requirements can achieve years of battery life and kilometers of long distance connection.

WISE-1510 has has received LoRaWAN certification from the LoRa Alliance. Depending on deployment requirements, developers can select to use Public LoRaWAN network services or build a private LoRa system with WISE-3610 LoRa IoT gateway. Advantech’s WISE-3610  is a Qualcomm ARM Cortex A7 based hardware platform with private LoRa ecosystem solution that can connect up to 500 WISE-1510 sensor node devices. Powered by Advantech’s WISE-PaaS IoT Software Platform, WISE-3610 features automatic cloud connection through its WISE-PaaS/WISE Agent service, manages wireless nodes and data via WSN management APIs, and helps customers streamline their IoT data acquisition development through sensor service APIs, and WSN drivers.

Developers can leverage microprocessors on WISE-1510 to build their own applications. WISE-1510 offers unified software—ARM Mbed OS and SDK for easy development with APIs and related documents. Developers can also find extensive resources from Github such as code review, library integration and free core tools. WISE-1510 also offers worldwide certification which allow developers to leverage their IoT devices anywhere. Using Advantech’s WISE-3610 LoRa IoT Gateway, WISE-1510 can be connected to WISE-  PaaS/RMM or  ARM Mbed Cloud service with IoT communication protocols including LWM2M, CoAP, and MQTT. End-to-end integration assists system integrators to overcome complex challenges and helps them build IoT applications quickly and easily.

WISE-1510 features and specifications:

  • ARM Cortex-M4 core processor
  • Compatible support for public LoRaWAN or private LoRa networks
  • Great for low power/wide range applications
  • Multiple I/O interfaces for sensor and control
  • Supports wide temperatures  -40 °C to 85 °C

Advantech | www.advantech.com

Analog ICs Meet Industrial System Needs

Jeff Lead Image Analog Inustrial

Connectivity, Control and IIoT

Whether it’s connecting with analog sensors or driving actuators, analog ICs play many critical roles in industrial applications. Networked systems add new wrinkles to the industrial analog landscape.

By Jeff Child

While analog ICs are important in a variety of application areas, their place in the industrial market stands out. Industrial applications depend heavily on all kinds of interfacing between real-world analog signals and the digital realm of processing and control. Today’s factory environments are filled with motors to control, sensors to link with and measurements to automate. And as net-connected systems become the norm, analog chip vendors are making advances to serve the new requirements of the Industrial Internet-of-Things (IIoT) and Smart Factories.

It’s noteworthy, for example, that Analog Devices‘ third quarter fiscal year 2017 report this summer cited the “highly diverse and profitable industrial market” as the lead engine of its broad-based year-over-year growth. Taken together, these factors all make industrial applications a significant market for analog IC vendors, and those vendors are keeping pace by rolling out diverse solutions to meet those needs.

Figure 1

Figure 1 This diagram from Texas Instruments illustrates the diverse kinds of analog sub-systems that are common in industrial systems—an industrial drive/control system in this case.

While it’s impossible to generalize about industrial systems, Figure 1 illustrates the diverse kinds of analog sub-systems that are common in industrial systems—industrial drive/control in that case. All throughout 2017, manufacturers of analog ICs have released a rich variety of chips and development solutions to meet a wide range of industrial application needs.

SOLUTIONS FOR PLCs

Programmable Logic Controllers (PLCs) remain a staple in many industrial systems. As communications demands increase and power management gets more difficult, transceiver technologies have evolved to keep up. PLC and IO-Link gateway systems must dissipate large amounts of power depending. That amount of power is often tied to I/O configuration—IO-Link, digital I/O and/or analog I/O. As these PLCs evolve into new Industrial 4.0 smart factories, special attention must be considered to achieve smarter, faster, and lower power solutions. Exemplifying those trends, this summer Maxim Integrated announced the MAX14819, a dual-channel, IO-Link master transceiver.

The architecture of the MAX14819 dissipates 50% less heat compared to other IO-Link Master solutions and is fully compatible in all modes for IO-Link and SIO compliance. It provides robust L+ supply controllers with settable current limiting and reverse voltage/current protection to help ensure robust communications with the lowest power consumption. With just one microcontroller, the integrated framer/UART enables a scalable and cost-effective architecture while enabling very fast cycle times (up to
400 µs) and reducing latency. The MAX14819 is available in a 48-pin (7 mm x 7 mm) TQFN package and operates over a -40°C to +125°C temperature range.  …

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Microcontrollers Target Smart Water Meters

Texas Instruments has unveiled a new family of MSP430 microcontrollers with an integrated ultrasonic sensing analog front end that enables smart water meters to deliver higher accuracy and lower power consumption. In addition, TI introduced two new reference designs that make it easier to design modules for adding automated meter reading (AMR) capabilities to existing mechanical water meters. The new MCUs and reference designs support the growing demand for more accurate water meters and remote meter reading to enable efficient water resource management, accurate measurement and timely billing.

New ultrasonic MCUs and new reference designs make both electronic and mechanical water meters smarter (PRNewsfoto/Texas Instruments Incorporated)

New ultrasonic MCUs and new reference designs make both electronic and mechanical water meters smarter.

As part of the ultra-low-power MSP430 MCU portfolio for sensing and measurement, the new MSP430FR6047 MCU family lets developers add more intelligence to flow meters by taking advantage of a complete waveform capture feature and analog-to-digital converter (ADC)-based signal processing. This technique enables more accurate measurement than competitive devices, with precision of 25 ps or better, even at flow rates less than 1 liter per hour. In addition, the integrated MSP430FR6047 devices reduce water meter system component count by 50 percent and power consumption by 25 percent, enabling a meter to operate without having to charge the battery for 10 or more years. The new MCUs also integrate a low-energy accelerator module for advanced signal processing, 256 KB of ferroelectric random access memory (FRAM), a LCD driver and a metering test interface.

The MSP430 Ultrasonic Sensing Design Center offers a comprehensive development ecosystem that allows developers to get to market in months. The design center provides tools for quick development and flexibility for customization, including software libraries, a GUI, evaluation modules with metrology and DSP libraries.

TI’s new Low-Power Water Flow Measurement with Inductive Sensing Reference Design is a compact solution for the electronic measurement of mechanical flow meters with low power consumption for longer battery life. Enabled by the single-chip SimpleLink dual-band CC1350 wireless MCU, this reference design also gives designers the ability to add dual-band wireless communications for AMR networks. Designers can take advantage of the reference design’s small footprint to easily retrofit existing mechanical flow meters, enabling water utilities to add AMR capability while avoiding expensive replacement of deployed meters. The CC1350 wireless MCU consumes only 4 µA while measuring water flow rates, enabling longer product life.

A second new reference design is an ultra-low power solution based on the SimpleLink Sub-1 GHz CC1310 wireless MCU. The Low-Power Wireless M-Bus Communications Module Reference Design uses TI’s wireless M-Bus software stack and supports all wireless M-Bus operating modes in the 868-MHz band. This reference design provides best-in-class power consumption and flexibility to support wireless M-Bus deployments across multiple regions.

Texas Instruments | www.ti.com

USB Data Acq System Features Simple Expansion

DATAQ Instruments has announced the release of its model DI-2108-P USB data acquisition (DAQ) system with 16-bit ADC resolution, programmable gain and ChannelStretch technology. The model DI-2108-P provides eight analog input channels each with 2.5-, 5- and 10-volt unipolar and bi-polar programmable measurement ranges. DATAQ Instruments di2108-product-photo-press-releaseThe DI-2108-P also provides 7 digital ports, each configurable as an input or a switch. Two ports can be programmed as counter and frequency measurement inputs. The instrument’s maximum sampling throughput rate is 160 kHz.

The ChannelStretch feature of the DI-2108-P makes channel expansion as easy as adding another device. Plug a second device into a computer and double the channel count of both analog and digital channels. Using USB hubs, plug up to sixteen devices into a single PC for a maximum count of 128 analog and 112 digital channels. And all of them are acquired synchronously at a maximum sample throughput rate of at least 480 kHz. DI-2108-P software support includes ready-to run WinDaq data acquisition software, .Net class, ActiveX controls and a fully documented communication protocol to deploy the instrument on any platform. The unit is priced at $349.

DATAQ Instruments | www.dataq.com

Getting Started with PSoC MCUs (Part 3)

Data Conversion, Capacitive Sensing and More

In the previous parts of this series, Nishant laid the groundwork for getting up and running with the PSoC. Here he tackles the chip’s more complex features like Data Conversion and CapSense.

By Nishant Mittal
Systems Engineer, Cypress Semiconductor

In the previous two parts of this “Getting started with PSoC” series, I have hopefully provided you with a good base of knowledge about PSoC devices. Here, in this final part it’s time to get more in depth and discuss various data conversion protocols in PSoC and provide some design examples. I’ll also cover interfacing various peripherals with the Photo 1microcontroller. We’ll also get into how to transition from a bare silicon PSoC chip or PSoC development board to using the chip in your project.

Data conversion with PSoC

Data Conversion is an important block in any kind of instrumentation system or Internet of Things implementation. In fact, any application that uses sensors or interfaces to the external environment is an application in which Data Conversion is an integral part of the system. Although digital sensors are available today, the lower costs of analog sensors shouldn’t be overlooked.

 

PSoC Creator has a Data Conversion component that enables designers to code efficiently with less effort. The photo above shows the screenshot of the ADC (analog-to-digital conversion) component in PSoC Creator. The photo above also shows the configuration setting for ADC. First off, we need to set the Channel sampling rate (SPS). Second, we need to set the voltage reference which is necessary to do the comparison of analog signals. Here we use VDDA/2 or VDDA which is 5 V. You can select whether you For web Figure 1want a single-ended ADC or differential ADC by simply clicking the appropriate tab from the component configuration. Clock source needs to be chosen. If the source is chosen to be internal, the PLL from the internals of chip are used—otherwise you’d have to connect an external crystal to the controller using the development kit CY8CKIT-044. Other advanced settings are available for complex programs—but most of those aren’t needed in most intermediate applications.

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16-Bit, 1.5-Msps Per Channel Octal Simultaneous Sampling SAR ADC

Linear Technology Corp. recently introduced the LTC2320-16 16-bit, 1.5-Msps per channel, no-latency successive approximation register (SAR) ADC. Featuring eight simultaneously sampling channels supporting a rail-to-rail input common mode range, the LTC2320-16 offers a flexible analog front end that accepts fully differential, unipolar or bipolar analog input signals. It also accepts arbitrary input signals and maintains an 82-dB signal-to-noise ratio (SNR) and high common mode rejection ratio (CMRR) of 102 dB when sampling input signals up to the Nyquist frequency. Linear LTC2320-16

 

The LTC2320-16’s specs, features, and benefits:

  • Wide input bandwidth enables the digitization of input signals up to the Nyquist frequency of 750 kHz
  • 1.5 Msps per channel throughput rate
  • Eight simultaneous sampling channels
  • ±2 LSB INL (typ)
  • Guaranteed 16-bit, no missing codes
  • 8.192 VPP true differential inputs with rail-to-rail common mode
  • 82-dB SNR (typ) at fIN = 500 kHz
  • –90-dB THD (Typ) at fIN = 500kHz
  • Guaranteed operation to 125°C
  • Single 3.3- or 5-V supply
  • Low drift (20 ppm/°C max) 2.048- or 4.096-V internal reference
  • 1.8-to-2.5-V I/O voltages
  • CMOS or LVDS SPI-Compatible Serial I/O
  • Power dissipation 20 mW/Ch (typ, 5-V operation)
  • 52-pin 7 mm × 8 mm QFN package

The LTC2320-16 is available in commercial, industrial, and automotive (–40° to 125°C) temperature grades. Pricing begins at $16.50 each in 1,000-piece quantities. The DC2395A evaluation board for the LTC2320 SAR ADC family is available at www.linear.com/demo.

Source: Linear Technology