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Utilize Simple Radios with Simple Computers

I ordered some little UHF transmitters and receivers from suppliers on AliExpress, the Chinese equivalent of Amazon.com, in order to extend my door chimes into areas of my home where I could not hear them. These ridiculously inexpensive units are currently about $1 per transmitter-receiver pair in quantities of five, including shipping, and are available at 315 and 433.92 MHz. Photo 1 shows a transmitter and receiver pair.  Connections are power and ground and data in or out.

Photo 1: 315 MHz Transmitter-Receiver Pair (Receiver on Left)

Photo 1: The 315-MHz transmitter-receiver pair (receiver on left)

The original attempt at a door chime extender modulated the transmit RF with an audio tone and searched for the presence of that tone at the receiver with a narrow audio filter, envelope detector, and threshold detector. This sort of worked, but I started incorporating the same transmitters into another project that interfered, despite the audio filter.

The other project used Arduino Uno R3 computers and Virtual Wire to convey data reliably between transmitters and receivers. Do not expect a simple connection to a serial port to work well. As the other project evolved, I learned enough about the Atmel ATtiny85 processor, a smaller alternative to the Atmel ATmega328 processor in the Arduino Uno R3, to make new and better and very much simpler circuits. That project evolved to come full circle and now serves as a better doorbell extender. The transmitters self identify, so a second transmit unit now also notifies me when the postman opens the mailbox.

Note the requirement for Virtual Wire.  Do not expect a simple connection to a serial port to work very well.


Figure 1 shows the basic transmitter circuit, and Photo 2 shows the prototype transmitter. There is only the ATtiny85 CPU and a transmitter board. The ATtiny85 only has eight pins with two dedicated to power and one to the Reset input.

Figure 1: Simple Transmitter Schematic

Figure 1: Simple transmitter schematic

One digital output powers the transmitter and a second digital output provides data to the transmitter.  The remaining three pins are available to serve as inputs.  One serves to configure and control the unit as a mailbox alarm, and the other two set the identification message the transmitter sends to enable the receiver to discriminate among a group of such transmitters.

Photo 2: 315 MHz Transmitter and ATtiny85 CPU

Photo 2: The 315-MHz transmitter and ATtiny85 CPU

When input pin 3 is high at power-up, the unit enters mailbox alarm mode. In mailbox alarm mode, the input pins 2 and 7 serve as binary identification bits to define the value of the single numeric character that the transmitter sends, and the input pin 3 serves as the interrupt input. Whenever input pin 3 transitions from high-to-low or low-to-high, the ATtiny85 CPU wakes from SLEEP_MODE_PWR_DOWN, makes a single transmission, and goes back to sleep. The current mailbox sensor is a tilt switch mounted to the door of the mailbox. The next one will likely be a reed relay, so only a magnet will need to move.

When in SLEEP_MODE_PWR_DOWN, the whole circuit draws under 0.5 µA. I expect long life from the three AAA batteries if they can withstand heat, cold, and moisture. I can program the ATtiny to pull the identification inputs high, but each binary identification pin then draws about 100 µA when pulled low. In contrast, the 20- or 22-MΩ pull-up resistors I use as pull-ups each draw only a small fraction of a microampere when pulled low.

When input pin 3 is low at power-up, the unit enters doorbell extender alarm mode. In doorbell extender alarm mode, the input pins 2 and 7 again serve as binary identification bits to define the value of the single numeric character that the transmitter sends; but in doorbell extender mode, the unit repetitively transmits the identification character whenever power from the door chimes remains applied.


Figure 2 shows the basic receiver circuit, and Photo 3 shows the prototype receiver. There is only the ATtiny85 CPU with a 78L05 voltage regulator and a receiver board.

Figure 2: Simple Receiver Schematic

Figure 2: Simple receiver schematic

The receiver output feeds the input at pin 5. The Virtual Wire software decodes and presents the received character. Software in the CPU sends tone pulses to a loudspeaker that convey the value of the identification code received, so I can tell the difference between the door chime and the mailbox signals. Current software changes both the number of beep tones and their audible frequency to indicate the identity of the transmit source.

Photo 3: The 315-MHz receiver with ATtiny85 CPU and 78L05 voltage regulator

Photo 3: The 315-MHz receiver with ATtiny85 CPU and 78L05 voltage regulator

Note that these receivers are annoyingly sensitive to power supply ripple, so receiver power must either come from a filtered and regulated supply or from batteries.

Photo 4 shows the complete receiver with the loudspeaker.

Photo 4: Receiver with antenna connections and loudspeaker

Photo 4: Receiver with antenna connections and a loudspeaker

Link Margin

A few inches of wire for an antenna will reach anywhere in my small basement. To improve transmission distance from the mailbox at the street to the receiver in my basement, I added a simple half-wave dipole antenna to both transmitter and receiver. Construction is with insulated magnet wire so I can twist the balanced transmission line portion as in Photo 5. I bring the transmission line out through an existing hole in my metal mailbox and staple the vertical dipole to the wooden mail post. My next mailbox will not be metal.

Photo 5: Simple half-wave dipole for both Tx and Rx increases link distance

Photo 5: Simple half-wave dipole for both Tx and Rx increases link distance

I don’t have long term bad weather data to show this will continue to work through heavy ice and snow, but my mailman sees me respond promptly so far.

Operating Mode Differences

The mailbox unit must operate at minimum battery drain, and it does this very well. The doorbell extender operates continuously when the AC door chime applies power. In order to complete a full message no matter how short a time someone presses the doorbell push button, I rectify the AC and store charge in a relatively large electrolytic capacitor to enable sufficient transmission time.

Photo 6: New PCBs for receive and transmit

Photo 6: New PCBs for receive and transmit


This unit is fairly simple to fabricate and program your self, but if there is demand, my friend Lee Johnson will make and sell boards with pre-programmed ATtiny85 CPUs. (Lee Johnson, NØVI, will have information on his website if we develop this project into a product: www.citrus-electronics.com.) We will socket the CPU so you can replace it to change the program. The new transmitter and receiver printed circuit boards appear in Photo 6.

Dr. Sam Green (WØPCE) is a retired aerospace engineer living in Saint Louis, MO. He holds degrees in Electronic Engineering from Northwestern University and the University of Illinois at Urbana. Sam specialized in free space and fiber optical data communications and photonics. He became KN9KEQ and K9KEQ in 1957, while a high school freshman in Skokie, IL, where he was a Skokie Six Meter Indian. Sam held a Technician class license for 36 years before finally upgrading to Amateur Extra Class in 1993. He is a member of ARRL, a member of the Boeing Employees Amateur Radio Society (BEARS), a member of the Saint Louis QRP Society (SLQS), and breakfasts with the Saint Louis Area Microwave Society (SLAMS). Sam is a Registered Professional Engineer in Missouri and a life senior member of IEEE. Sam is listed as inventor on 18 patents.

SoC FPGA Development Kit for Audio & Processing Applications

Coveloz recently announced the availability of its Pro Audio Ethernet AVB FPGA Development Kit, which is a ready-to-play platform for building scalable, cost-effective networked audio and processing applications built on modular hardware.Covelozpro-audio-dev-kit

Coveloz introduced its Networked Pro Audio SoC FPGA Development Kit during the Integrated System Europe (ISE) show in Amsterdam. According to the company, the new platform will enable manufacturers to achieve faster AVnu certification for new AVB solutions, creating an ideal development environment for live sound, conferencing systems, public address, audio post production, music creation, automotive infotainment and ADAS applications.

At the heart of the Coveloz development platform is a highly integrated System-on-Module (SOM), featuring an Altera Cyclone V SoC FPGA, which includes a dual-core ARM A9 processor, DDR3 memory and a large FPGA fabric, all in a low cost and compact package. The kit includes a multitude of networking and audio interfaces, including three Gigabit Ethernet ports as well as I2S, AES10/MADI, AES3/EBU and TDM audio.

Coveloz provides FPGA and Linux firmware enabling designers to quickly build AVnu Certified products for the broadcast, pro-audio/video and automotive markets. The platform is aimed at time-synchronized networks and includes grandmaster, PPS and word clock inputs and outputs as well as high quality timing references.

The Coveloz development kit is also host to the BACH-SOC platform, which integrates AES67 and Ethernet AVB audio networking and processing. Both SoC and PCIe-based FPGA implementations are available.

The Coveloz Bach Module is a full-featured and programmable audio networking and processing solution for easily integrating industry-standard AES67 and/or Ethernet AVB/TSN networking into audio/video distribution and processing products. The solution enables products with over 128+128 channels of digital streaming and 32-bit audio processing at 48, 96, or 192 kHz.

Supporting a wide range of interfaces, Coveloz complements the development platform with a comprehensive software toolkit and engineering services to help manufacturers reducing time to market. Coveloz also provides application examples to demonstrate the capabilities of the BACH-SOC platform.

The programmable BACH-SOC can be customized to a particular application in many ways—for instance, from selecting the number and type of audio interface to choosing audio processing alone, transport alone, or a combination.

Source: Coveloz

Online Classroom for Analog Design

Texas Instruments recently launched TI Precision Labs, which is a comprehensive online classroom for analog engineers to take on-demand courses. The free, modular curriculum includes more than 30 training experiences and lab videos covering analog amplifier design considerations with online coursework.TI OnlineClassroomAnalog

TI Precision Labs incorporates a variety of tools to bring the online training experience to life. A $199 TI Precision Labs Op Amp Evaluation Module (TI-PLABS-AMP-EVM) enables engineers to complete each demonstrated learning activity along with the trainer. The curriculum also provides access to free design tools, such as TI Designs reference designs and TI’s TINA-TI SPICE model simulator.

Engineers can evaluate circuits and small-signal AC performance created during the trainings with National Instruments’s VirtualBench all-in-one instrument and TI’s Bode Analyzer Software for VirtualBench, as well as standard engineering bench equipment.

Key features and benefits of TI Precision Labs:

  • Experiential learning applies theory to real-world, hands-on examples with lab demonstration videos.
  • A customized learning environment provides recommended training tracks on topics such as noise, bandwidth and input/output swing, while enabling engineers to pick and choose courses based on individual needs and interests.
  • Accelerated learning for recent graduates eases the transition from undergraduate theoretical-based learning to real-world designing.
  • Robust learning materials include a downloadable presentation workbook and lab manual, as well as TI’s Analog Engineer’s Pocket Reference, which puts commonly used board- and system-level formulas at your fingertips.
  • Expert support: A TI Precision Labs support forum is available on the TI E2E Community to answer questions resulting from the training.

The TI Precision Labs training curriculum is free to anyone with a myTI account. In addition to free training, other benefits of myTI registration include the ability to purchase TI integrated circuits (ICs), evaluation modules, development kits and software; request product samples; get technical assistance through the TI E2E Community; create, simulate and optimize systems in the WEBENCH Design Center; and more.
TI Precision Labs curriculum is housed in the new TI Training Center, which connects engineers with the technical training they need to find solutions to their design challenges anytime, anywhere.

In addition to the on-demand courses, in-person, hands-on trainings covering a variety of precision amplifier topics, such as noise, offset, input bias, slew rate and bandwidth, are scheduled for May in Schaumburg, IL and Pewaukee, WI. Both live trainings require registration and cost $99 to attend. More in-person training dates in the United States will be added.

Source: Texas Instruments

20-µA Op-Amp for 30-µV Precision

Linear Technology’s LT6023 is a dual 3-to-30-V low-power operational amplifier that features 30-µV maximum input offset voltage and 60 µs settling to 0.01%. Proprietary slew enhancement circuitry results in a fast, clean output step response with low power consumption. Specially designed input circuitry maintains high impedance, which minimizes current spikes associated with fast steps for input steps up to 5 V. Together these features make the LT6023 an ideal for portable high-precision instruments, multiplexed data acquisition systems, and DAC buffer applications.Linear LT6023

The LT6023-1 includes a shutdown mode, which reduces the supply current to less than 3 µA when the amplifier is not active. Enable time of 480 µs and fast slew rate combine to provide power-efficient operation in duty-cycled applications, such as those featuring Linear Technology’s Dust Networks wireless sensor network products.

Summary of Features: LT6023

  • 30 µV Max Input Offset Voltage (MSOP Package)
  • Excellent Slew Rate to Power Consumption Ratio
  • 1 V/µs Slew Rate (10 V step)
  • 20 µA Max Supply Current
  • 3 nA Max Input Bias Current
  • 3 V to 30 V Supply Range
  • Output Swings Rail-to-Rail
  • –40°C to 125°C Specified Temperature Range
  • 3 A Max Shutdown Mode (LT6023-1)
  • 8-Lead MSOP & 3 × 3 mm DFN Packages

Fully specified over the –40°C to 85°C and –40°C to 125°C temperature ranges, the LT6023 is available in MSOP-8 and 3 × 3 mm DFN packages. Prices start at $1.85 each in quantities of 1,000 units.

Source: Linear Technology

CAN Flexible Data-Rate Transceiver Family

Microchip Technology recently launched the MCP2561/2FD family of CAN Flexible Data-Rate (FD) transceivers. As an interface between a CAN controller and the physical two-wire CAN bus, the transceivers work for both the CAN and CAN FD protocols. Thus, the family helps automotive and industrial manufacturers with current CAN communication needs and provides a path for newer CAN FD networks.Microchip MCP25612FD CAN FD transceivers

In-vehicle networking growth continues to be driven by the need for electronic monitoring and control. As application features in power train, body and convenience, diagnostics and safety increase, more Electronic Control Units (ECUs) are being added to existing CAN buses, causing automotive OEMs to become bandwidth limited. In addition, the end-of-line programming time for ECUs is on the rise due to more complex application programs and calibration, which raises production line costs. The emerging CAN FD bus protocol solves these issues by increasing the maximum data rate while expanding the data field from 8 data bytes up to 64 data bytes.

With their robustness and industry-leading features, including data rates of up to 8 Mbps, Microchip’s MCP2561/2FD transceivers enable customers to implement and realize the benefits of CAN FD. These new transceivers have one of the industry’s lowest standby current consumption (less than 5 µA typical), helping meet ECU low-power budget requirements. Additionally, these devices support operation in the –40°C to 150°C temperature range, enabling usage in harsh environments.

The new family of MCP2561/2FD CAN FD transceivers is available in eight-pin PDIP, SOIC and 3 × 3 mm DFN (leadless) packages, providing additional design flexibility for space-limited applications. The family also provides two options. The MCP2561FD comes in an 8-pin package and features a SPLIT pin. This SPLIT pin helps to stabilize the common mode in biased split-termination schemes. The MCP2562FD is available in an eight-pin package and features a Vio pin. This Vio pin can be tied to a secondary supply in order to internally level shift the digital I/Os for easy microcontroller interfacing. This is beneficial when a system is using a microcontroller at a VDD less than 5 V (e.g., 1.8 V or 3.3 V), and eliminates the need for an external level translator, decreasing system cost and complexity.

The MCP2561FD and MCP2562FD transceivers are both available now for sampling and volume production in 8-pin PDIP, SOIC and 3 × 3 mm DFN packages, starting at $0.69 each, in 5,000-unit quantities.

Source: Microchip Technology

Microcontroller-Based Sentry System

David Penrose’s “Sentry” project comprises an array of passive IR sensors placed throughout a building to track motion. The microcontroller-based system comprises an RF link to a processor along with an Ethernet module to unobtrusively monitor motion and activity levels.

The Sentry system uses commercial IR motion sensors (lower left) together with a customer vibration sensor (lower right) to determine where an individual is within a building. The base unit (top) integrates reports from these sensors to generate alerts to a caregiver.

Photo 1: The Sentry system uses commercial IR motion sensors (lower left) together with a customer vibration sensor (lower right) to determine where an individual is within a building. The base unit (top) integrates reports from these sensors to generate alerts to a caregiver.

Penrose writes:

My Sentry System is designed to assist those folks living alone who desire the peace of mind provided by a caregiver looking after them without the caregiver having to be present. Its implementation was facilitated by the WIZnet WIZ550io Ethernet module, which provides a rich yet simple interface to the Internet. With a simple microprocessor, the system allows the status of a resident to be continuously monitored in a minimally intrusive fashion.

Any abnormal conditions can immediately be alerted to a remote caregiver for action. In this way, a caregiver’s smartphone acts as an alert system by letting them know when a resident’s activity deviates from a normal pattern. The system is designed to be simple to set up yet very flexible in its application so the needs of different residents can be addressed. A resident with minimal needs can be monitored by a set of relaxed rules, while a resident in need of more continuous observation can be assigned a set of strict rules. In all cases, the overarching design approach was to provide a system that augments the caregiver’s capability.

Penrose goes on to describe the system:

The Sentry System integrates motion sensors, a microprocessor, and the WIZ550io Ethernet interface to monitor a resident and report abnormal activity patterns to a remote caregiver (see Photo 1). The relationship of these subsystems is illustrated in Figure 1.

Up to eight sensors transmit activity to a base unit processor, which checks for abnormal behavior of a resident. Alerts to a caregiver are generated and communicated over the Internet.

Figure 1: Up to eight sensors transmit activity to a base unit processor, which checks for abnormal behavior of a resident. Alerts to a caregiver are generated and communicated over the Internet.

The primary sensors are IR motion sensors. These can be augmented by vibration sensors, pressure mats, ultrasonic, and other devices capable of detecting a person’s presence. These sensors are placed at key locations in a resident’s home to monitor movement from room to room or within rooms. The vibration sensors are placed in favorite chairs/couches or in the bed to determine if the furniture is occupied and if there is normal activity. All of these sensors are battery powered and report over an RF link. The RF reports from these devices are received by a base unit which then compares the resident’s location and activity to a set of rules that define normal behavior for different times of day. Any deviation from normal results in an SMS text message or e-mail being sent to the caregiver along with information about how to contact the resident. In most cases, it is expected that the caregiver would respond by phoning the resident to check on them.

The system is designed to be easy to install and operate. The WIZ550io’s Internet interface is used to communicate to a browser allowing the caregiver or resident to configure the system. This configuration consists of identifying sensors and rooms and describing a set of rules for each room for periods in the day. This local interface also allows for a review of all past activity once the system is operational. This history data is valuable for refining the rules to reduce false alarms and ensure security. Since the interface is behind the resident’s firewall, the system is secure from improper modification. The key output from the system is the alert to the caregiver, which relies on the WIZ550io module communicating to a service site such as Exosite. The site generates the alerts sent to the caregiver.

The base unit incorporates the WIZ550io, an 89LPC936 processor, a MCP79401 real-time clock, and a serial EEPROM to process reports received from the 433-MHz receiver.

Photo 2: The base unit incorporates the WIZ550io, an 89LPC936 processor, a MCP79401 real-time clock, and a serial EEPROM to process reports received from the 433-MHz receiver.

The system’s hardware consists of a base unit and multiple sensor/reporting units. The base unit (see Photo 2) comprises a WIZ550io Ethernet interface, an inexpensive microprocessor, an RF receiver, a battery backed-up real-time clock, and a serial EEPROM. All of these pieces are integrated into a small form factor case and powered by a plug-in transformer (see Figure 2).

Figure 2: The microprocessor accomplishes all of its tasks while using only a few of the available port pins.

Figure 2: The microprocessor accomplishes all of its tasks while using only a few of the available port pins.

The remote units can be one of many different sensor/reporting devices depending on the needs of the resident. The basic sensor is the IR motion sensor, which is available from a number of different sources.  I used Bunker Hill Security sensors, which I purchased from Harbor Freight Tools (Item 93068). A sensor plus receiver is very inexpensive. Some cost only $11. The item consists of a sensor/transmitter and a receiver/alarm device. The receiver/alarm device is not used in this project although the RF receiver was lifted from one of these units to provide the receiver for the base unit. These sensor units are powered by 9-V batteries and report on an RF link at 433 MHz with a unique address code.  The code allows multiple sensors to be deployed and recognized by the base unit.

The complete article appears in Circuit Cellar 296 (March 2015).

5-V Qi Low-Power Wireless Charging Transmitter Reference Design

NXP Semiconductors has announced the availability of a new reference design for 5-V low-power Qi wireless charging transmitters, compliant with the Wireless Power Consortium (WPC) 1.1 Qi specification. The design is based on NXPs single-chip 5-V wireless power transmitter IC—the NXQ1TXA5 that was launched in 2014. It is the latest addition to NXP’s portfolio of Greenchip power solutions.NXP NXQ1TXA5

Building on NXP’s success as the market leader in Greenchip power ICs, the NXQ1TXA5 reference design has an unrivalled standby power consumption of less than 10 mW. It is the only solution on the market today that meets five-star mobile phone charger standby power ratings by consuming less than 30 mW in standby mode, which includes the standby power of the wall-charger. NXP recommends combining its NXQ1TXA5 ultra low standby power wireless power transmitter solution with another Greenchip device, its high efficiency TEA1720 SMPS IC with a standby power of less than 20 mW.

The NXQ1TXA5 device combines:

  • NXPs patented high efficiency Class D amplifier technology for outstanding EMI performance.
  • NXP’s ultra low power CoolFluxTM DSP technology for superior communication with smartphones placed on the charger.
  • Dedicated low power mixed signal circuitry to check for smartphone presence three times per second, enabling fast startup of charging, while keeping the standby power very low if there is no smartphone on the charger.

Due to the NXQ1TXA5’s  low-power consumption, the reference design also has a high efficiency for low transmitted powers, making it suitable for applications ranging from smartphone charging to deliver 5 W to the smartphone battery when used with a Qi compliant wireless charging receiver, to chargers for wearables that need less than 2-W charging power.

The NXQ1TXA5 reference design needs only 15 to 20 low-cost passive components and uses a standard two-layer PCB, with the components mounted on a single side. Depending on customer requirements, the complete application can be designed on a board space as small as 3 × 3 or 4 × 4 cm.

The new NXQ1TXA5 wireless charging transmitter reference design will be available in Q2.

Source: NXP Semiconductors

5-GHz Power Amplifier Module for WLAN Applications

Microchip Technology has announced a new SST11CP22 5-GHz power amplifier module (PAM) for the IEEE 802.11ac ultra high data rate Wi-Fi standard. This PAM delivers 19-dBm linear output power at 1.8% dynamic Error Vector Magnitude (EVM) with MCS9 80-MHz bandwidth modulation. The SST11CP22 delivers 20-dBm linear power at 3% EVM for 802.11a/n applications. It is spectrum mask compliant up to 24 dBm for 802.11a communication, and it has less than –45-dBm/MHz RF harmonic output at this output power, making it easier for the system board to meet FCC regulations.Microchip SST11CP22

Achieving the maximum data rate and longest range while minimizing current consumption is essential to Wi-Fi MIMO access-point, router and set-top-box system designers. The SST11CP22’s low EVM and high linear power facilitate MIMO operation and significantly extend the range of 802.11ac systems in ultra-high data rate transmission mode. The module, housed in a space-saving 4 × 4 mm, 20-pin QFN package, includes an output harmonic rejection filter and is 50 Ohm-matched—requiring only four external components. It is easy to use and reduces board size. Additionally, the integrated linear power detector provides accurate output power control over temperature and 2-to-1 output mismatch. These features are critical for 802.11ac Wi-Fi set-top boxes, routers, access points, and wireless video streaming devices that operate at high data rates.

Developers can begin designing today with the SST11CP22 Evaluation Board (SST11CP22-GN-K). The SST11CP22 RF Power Amplifier Module is available in a 4 × 4 mm, 20-pin QFN package for $0.92 each in 10,000-unit quantities. Sampling and volume production are both available now.

Source: Microchip Technology

OptiMOS Product Family Exceeds 95% Efficiency

Infineon Technologies recently launched the OptiMOS 5 25- and 30-V product family, the next generation of Power MOSFETs in standard discrete packages, a new class of power stages named Power Block, and in an integrated power stage, DrMOS 5×5. Together with Infineon’s driver and digital controller products the company delivers full system solutions for applications such as server, client, datacom or telecom.Infineon-OptiMOS

The newly introduced OptiMOS family offers benchmark solutions with efficiency improvements of around 1% across the whole load range compared to its previous generation, exceeding 95% peak efficiency in a typical server voltage regulator design. This improved performance is based for example on the reduction of switching losses (Q switch) by 50% compared to the previous OptiMOS technology. Thus, implementing the new OptiMOS 25 V would lead to energy savings of 26.3 kWh per year for a single 130-W server CPU working 365 days.

The launch of the OptiMOS product family is accompanied by the introduction of a new packaging technology offering a further reduction in PCB area consumption. It is used in the Power Block product family and in the integrated powerstage DrMOS 5×5 and offers a source down low-side MOSFET for improved thermal performance, with a reduction by 50% of the thermal resistance in comparison to standard package solution, such as SuperSO8.

Infineon`s Power Block is a leadless SMD package comprising the low-side and high-side MOSFET of a synchronous DC/DC converter into a 5.0 × 6.0 mm 2 package outline. With Power Block, customers can shrink their designs up to 85 percent by replacing two separate discrete packages, such as SuperSO8 or SO-8. Both, the small package outline and the interconnection of the two MOSFETs within the package minimize the loop inductance for best system performance.

OptiMOS 5 25V is also used in an integrated power stage, combining DrMOS 5×5, driver and two MOSFETs, for a total area consumption on the PCB equal to 25mm². The integrated driver plus MOSFETs solution results in a shorter design time and is easy to design-in. Additionally, the dovetailed power stage includes a high accurate temperature sense of +/-5°C (compared to +/-10°C of an external one) which enables higher system reliability and performance.

Samples of the new OptiMOS 25- and 30-V devices in SuperSO8, S3O8 and Power Block packages, with on-state resistances from 0.9 mΩ to 3.3 mΩ are available. Additional products with monolithic integrated Schottky-like diode and products in 30 V will be available from Q2 2015 onwards. DrMOS 5×5 will be released in Q2 2015. Samples are available.

Source: Infineon

Synchronous Buck Regulator with Output Tracking and Sequencing for FPGAs and Microprocessors

Intersil Corp. recently announced the availability of the ISL8002B synchronous buck (step-down) switching regulator, which delivers up to 2 A of continuous output current from a 2.7- to 5.5-V input supply. Its 2-MHz switching frequency provides superior transient response, and its key features—including programmable soft-start and output tracking and sequencing of FPGAs and microprocessors—increase system reliability for point-of load conversions in networking, factory automation, instrumentation, and medical equipment.Intersil ISL8002B

The ISL8002B enables greater system reliability through several innovative features. For example, the regulator’s output tracking and sequencing of FPGAs and MPUs ensures sensitive multi-rails properly start up and shutdown. In addition, its output rails are configurable for coincidental, ratio metric, or sequential settings, ensuring the FPGA or MPU’s internal ESD diodes are not biased or overstressed during rising or falling outputs. The ISL8002B’s undervoltage lockout and several other protection/stability features protect the system from damage from unwanted electrical fault events. And its unique negative current protection prevents switch failure.

The ISL8002B’s superior transient response and high level of integration enable a complete synchronous step-down DC/DC converter solution in less than a 0.10 in2 footprint. By integrating low RDS(ON) high-side PMOS and low-side NMOS MOSFETs, the buck regulator eliminates the need for a bootstrap capacitor and diode. Its high efficiency enables the use of small inductors to further reduce board space.

Features and specifications:

  • Dimensions: 2 mm × 2 mm
  • Output tracking and sequencing
  • Switching at high frequency, 2 MHz
  • High peak efficiency: up to 95%
  • Wide input voltage range: 2.7 to 5.5 V
  • Maximum output current: 2A
  • Under voltage lockout, overvoltage protection
  • Selectable PFM or PWM operation
  • Over current, short-circuit protection
  • Over temperature/thermal protection

The ISL8002B synchronous buck regulator is available in a 2 mm  × 2 mm, eight-pin TDFN package. It costs $1 in 1,000-piece quantities. The ISL8002B DEMO1Z demonstration board is available for $23.

Source: Intersil Corp.



27-GHz Bandwidth Socket for Xilinx FLGA2577 BGA Package

Ironwood Electronics recently introduced a new high-performance BGA socket for 1-mm pitch, 2577 pin BGA ICs. The SG-BGA-6422 socket is designed for IC size 52.5 × 52.5 mm and operates at bandwidths up to 27 GHz with less than 1 dB of insertion loss. The sockets are designed to dissipate up to several watts without extra heat sinking and can handle up to 100 W with custom heat sink. The contact resistance is typically 20 mΩ per pin. The socket connects all pins with 27-GHz bandwidth on all connections. The socket is mounted on the target PCB with no soldering and uses industry’s smallest footprint. The socket is constructed with shoulder screw and swivel lid which incorporates a quick insertion method so that ICs can be changed out quickly. The socket comes with ball guide for the precise alignment of BGA balls to PCB pads.Ironwood C14363b

The SG-BGA-6422 socket is constructed with high performance and low inductance elastomer contactor. The temperature range is –35°C to 100°C. The pin self inductance is 0.15 nH and mutual inductance of 0.025 nH. Capacitance to ground is 0.01 pF. Current capacity is 2 A per pin. It works with ICs such as Xilinx BGA, 52.5-mm square package with 51 × 51 array and 1-mm pitch.

The SG-BGA-6422 is $1805, with reduced pricing available depending on the quantity required.

Source: Ironwood Electronics

Embedded SIM Controllers for Secure M2M Communication

Secure cellular Machine-to-Machine (M2M) communication enables automated data exchange. Infineon Technologies recently announced the SLM 97 and SLI 97 security controller families. The new products stand out with unique features required for M2M communication in industrial as well as automotive applications such as emergency Call (eCall) and Vehicle-to-Vehicle (V2V) communication.Infineon SLI97-SLM97

For the past 10 years, Infineon has provided high-quality security controllers used for M2M applications in the industrial and automotive sectors. For instance, Infineon supplies leading European car manufacturers with security controllers for eCall and other connectivity solutions for vehicles.

With the launch of the new SLM 97 and SLI 97 product families, Infineon strengthens its position in the growing industrial M2M and connected car markets. The new products enable the full implementation of embedded SIM as defined by GSMA and ETSI, increasing flexibility and simplifying the deployment of new M2M solutions.

Both SLM 97 and SLI 97 provide the following:

  • an extended temperature range from –40° to 105°C and high endurance for operation in demanding industrial and automotive environments
  • up to 1-MB SOLID FLASH memory, allowing fast prototyping and shortening time-to-market for device manufacturers
  • a set of hardware crypto-coprocessors supporting all relevant crypto schemes
  • a wide range of interfaces including ISO7816, SWP, USB, I2C, SPI to address a large variety of industrial and automotive applications
  • Common Criteria EAL 5+ (High) certification

The SLM 97 security controllers are tailored to industrial M2M applications requiring high endurance and robustness. They are qualified according to internationally recognized industrial standards and delivered in standard embedded M2M packages as well as in standard SIM card module.

The SLI 97 security controllers are qualified according to the high quality automotive standards (AEC-Q100) and tailored to the difficult environmental conditions of automotive applications. They pass through exhaustive quality processes to minimize failure rates. This makes them the perfect products for SIM cards or embedded security products in connected cars. Both families are based on field-proven products deployed in traditional Smart Card markets worldwide.

Source: Infineon Technologies

Static Code Analysis for MSP430 Microcontrollers

IAR Systems, the leading vendor of embedded development tools, is proud to introduce its latest product innovation C-STAT. C-STAT provides powerful static analysis and is now available fully integrated in the high-performance development toolchain IAR Embedded Workbench for Texas Instruments’s (TI) MSP430 MCUs.IAR C-STAT

Important concerns for embedded developers today include adherence to coding standards, as well as increased application complexity that might interfere with code quality. Using a flexible static code analysis tool like C-STAT addresses both these issues by detecting potential code errors in complex applications and by ensuring compliance with coding standards applicable for embedded applications in various segments.

C-STAT is a powerful static analysis tool that executes fast and provides analysis results directly in the IAR Embedded Workbench IDE. It checks compliance with rules as defined by coding standards including MISRA C:2004, MISRA C++:2008 and MISRA C:2012, as well as hundreds of rules based on, for example, the Common Weakness Enumeration (CWE) and CERT C/C++. Users can easily select which rule-set or which individual rules to check the code against. The tool detects potential code errors including for example memory leaks, access violations, arithmetic errors and array and string overruns. By finding such errors early, developers can take full control of their code and lower the risk of breaking the budget and deadline for a project.

Source: IAR Systems

New SQI Interface SuperFlash Memory Devices

Microchip Technology recently launched the SST26VF family of 3-V Serial Quad I/O interface (SQI interface) SuperFlash memory devices. Available with 16-, 32- or 64-Mb of memory, the “26 Series” family is manufactured using Microchip’s high-performance CMOS SuperFlash technology.

The SST26VF memory family provides fast erase times due to its use of SuperFlash technology. Sector and block erase commands are completed in just 18 ms, and a full chip erase operation is completed in 35 ms. Competitors’ devices require 10 to 20 s to complete a full chip erase operation, making the SST26VF approximately 400× faster. These fast erase times can provide a significant cost savings to customers, by minimizing the time required for testing and firmware updates, and therefore increasing their manufacturing throughput.Microchip SST26VF

Microchip’s SQI interface is a low pin count, high-speed 104 MHz quad-bit address and data multiplex I/O serial interface, which allows for high data throughput in a small package. This interface enables low-latency execute-in-place (XIP) capability with minimal processor buffer memory, reducing the overall design footprint compared to traditional parallel memory interfaces. The SST26VF family provides faster data throughput than a comparable x16 parallel flash device, without the associated high cost and high pin count of parallel flash. The SQI interface also offers full command-set backward compatibility for the ubiquitous SPI protocol.

Designed for low power consumption, the SST26VF is ideal for energy-efficient embedded systems. Standby current consumption is 15 µA (typical), and the active read current at 104 MHz is 15 mA (typical). The combination of 3-V operation with low power consumption and small-form-factor packaging makes the SST26VF devices an excellent choice for applications such as servers, printers, cloud computing systems, HDTV, Internet gateways, appliances, security systems, and a broad range of embedded systems.

The SST26VF devices also offer 100 years of data retention and device endurance of over 100,000 erase/write cycles. Enhanced safety features include software write protection of individual blocks for flexible data/code protection. In addition, the upper and lower 64 KB of memory are partitioned into smaller, 8-KB sectors that can both read- and write-lock. In addition, the devices include a One-Time Programmable (OTP) 2-KB Secure ID area, consisting of a 64-bit, factory-programmed unique ID and a user-programmable block. These features protect against unauthorized access and malicious read, program and erase intentions. The devices also include a JEDEC-compliant Serial Flash Discoverable Parameter (SFDP) table, which contains identifying information about the functions and capabilities of the SST26VF devices for simpler software design.

The three-member SST26VF family is available now for sampling and volume production in multiple package options, including eight-pin SOIC and SOIJ, 16-pin SOIC, eight-contact WDFN and 24-ball TBGA, as well as in die and wafer form. In 10,000-unit quantities, the 16-Mb SST26VF016B starts at $0.90 each, the 32-Mbit SST26VF032B starts at $1.17 each, and the 64-Mbit SST26VF064B starts at $1.84 each.

Source: Microchip Technology

The Future of Flexible Circuitry

The flexible circuit market has been growing steadily for the last three decades. This trend will continue into the foreseeable future as flexible circuitry supports many of the same industries and many of the same applications that have been around for more than 30 years. Past and current industries include military and avionics with most of these applications being high layer count, high-density rigid flex, and also consumer electronics, telecom, and automotive applications with flex circuit designs that are typically less complex than those of mil/aero. Medical diagnostic applications will continue to grow as new equipment is developed and older equipment is refurbished or redesigned. But if I had to sum up an answer to the question “where is flex going in the near future?” my answer would be simply “on you.”

The wearable electronics market has absolutely exploded in the last few years with new applications emerging almost daily. If an electronic device is going to be worn on the body comfortably, it has to be flexible. So what better way to provide interconnects for these types of devices than a flex circuit? Here are just a few of the current and emerging wearable products that contain flexible circuitry.

Wrist-Worn Activity and Body Function Monitors: Electronic watches were some of the first wearable electronics, so it was just a natural progression to include more advanced functionality than just time keeping. Wrist-worn activity monitors are light weight and use multiple axis accelerometers and other sensors to detect motion and body functions. They can capture and record daily activity levels as well as sleep cycles. This data is stored in on-board memory in the device until it can be downloaded to the user’s mobile phone. Since the human hand is larger than the wrist, these monitoring bands need to be able to expand when the user is putting it on or taking it off. Flexible circuits allow the band to flex while maintaining connectivity across flexing sections.

Foot-Worn Sensors: I have seen a lot of applications recently for electronics that are worn on the foot or inside the shoe. Foot-worn electronics monitor everything from steps taken when running or walking to stride irregularities that can contribute to back problems. These sensors need to be very thin in order to be comfortable and also very robust to survive in what I would consider a pretty hostile environment. Flexible circuitry is thin enough to lay on the sole of a shoe and be almost undetectable to the wearer.

Wearable Baby Monitors: Baby monitors are one of the newer products in the wearable electronics market. New parents no longer have to rely on a simple walkie talkie system to keep tabs on their little ones while they sleep. These monitors can be worn on the baby’s leg or in their clothing and can keep track of breathing, heartbeat, body temperature, etc. If the device senses that there is a problem, an alert is sent to the parents phone to wake them. It is almost like having a private nurse watching the child all night long.

Medical Sensors: This is an area that has been growing rapidly, and I predict that the trend will continue at an accelerated rate. With today’s push to get patients out of the hospital as quickly as possible, electronic home monitoring of the patient is going to be necessary. There are currently sensors that can be worn by the patient for several days at a time, while keeping tabs on heart functions continuously during this time. Just like the baby monitor referred to earlier, these devices can send alerts to the patient’s physician if any abnormalities are detected. These devices will allow a patient to recover from heart attack or surgery in the comfort of their own home while still having continuous monitoring of their state of health.

Pet Monitors: Even Rover gets to wear electronics these days. Training collars have been around for a while, but now thanks to shrinking electronics there are collars that contain GPS and mobile phone capabilities. Today a lost pet can use the GPS to figure out where he is and call his owner for a ride home! Not really, but if your pet is wearing one of these devices he is never truly lost. The mobile phone module is used to transmit the GPS coordinates to tracking service, where the owner can log on and track the pet’s location to within a few feet.

Clothing Worn Electronics: This is an area that is just starting to emerge, and new technology is being developed to support these applications. Standard flex circuitry is constructed from a combination of polyimide film, thermo-setting film adhesive, and copper foil. Unfortunately, flex circuits fabricated with these materials will not survive the crumpling that they would be exposed to in a washing machine. I have seen several applications where flex has been incorporated into clothing that does not need to be machine washed (e.g., flexible heaters in winter gloves). The key to making this type of wearable application machine washable is to make the flex circuit not only flexible, but also stretchable. This means that both conductors and dielectrics must be developed that will allow the finished product to stretch and still maintain electrical continuity. This technology is not mainstream yet, but it is on its way.

These examples are just a small sampling of the applications that are currently on the market, and there are many others in development. As more and more of these applications emerge, flexible circuitry will continue to be the interconnect method of choice.

Mark Finstad is a Senior Application Engineer at Flexible Circuit Technologies in Minneapolis, MN. He is a nationally recognized expert in the design, fabrication, and test of flexible and rigid flex printed circuits with more than 30 years of experience in the flexible PCB industry.

This article appears in Circuit Cellar 296 (March 2015).