About Circuit Cellar Staff

Circuit Cellar's editorial team comprises professional engineers, technical editors, and digital media specialists. You can reach the Editorial Department at editorial@circuitcellar.com, @circuitcellar, and facebook.com/circuitcellar

New High-Speed CMOS DDR2 Synchronous DRAMs

Alliance Memory recently broadened its line of high-speed CMOS double data rate 2 synchronous DRAMs (DDR2 SDRAM). Its new device featuring high 2-Gb density in a 84-ball 8-mm × 12.5-mm × 1.2-mm FBGA package. The AS4C128M16D2 is available (from a limited number of suppliers) in commercial (0°C to +85°C) and industrial (–40°C to +95°C) temperature ranges.AllianceMemory-DDR2 SDRAM

The AS4C128M16D2 provides a drop-in, pin-for-pin-compatible replacement for a number of similar solutions in industrial, auto, consumer, networking, and medical products that require high memory bandwidth. It is internally configured as eight banks of 16M × 16 bits. The RoHS-compliant DDR2 SDRAM includes a synchronous interface and operates from a single 1.8-V (±0.1 V) power supply. In addition, it features a fast clock rate of 400 MHz and a data rate of 800 Mbps/pin. The DDR2 SDRAM provides programmable read or write burst lengths of 4 or 8. An auto precharge function provides a self-timed row precharge initiated at the end of the burst sequence. Easy-to-use refresh functions include auto- or self-refresh while a programmable mode register allows the system to choose the most suitable modes to maximize performance.

With the AS4C128M16D2, Alliance Memory now offers a variety of DDR2 SDRAMs with densities of 512 Mb, 1 Gb, and 2 Gb. Samples of the AS4C128M16D2 are available now, with lead times of six to eight weeks for production quantities. Pricing for US delivery starts at $6.50 per unit.

Source: Alliance Memory

How To Measure Temperature with a Soldering Iron

Forget those expensive temperature sensors. Now you can use an ordinary heating element like a soldering iron to measure temperature. Daniel Maliks’s upgraded soldering iron will be a great addition to your workbench.

In Circuit Cellar 191, Malik writes:

There are many applications that involve the conversion of electric current into heat by means of a heating element with some degree of temperature control. Hot water boilers, kettles, and irons are typical examples. In this article, I’ll explain how you can eliminate the need for a temperature sensor by using the heating element itself to accurately measure temperature.

dsa

The finished soldering station. Think of it as a heating element turned temperature sensor.

I appreciate that electronics enthusiasts don’t necessarily want to read about cooking and ironing. So, I’ll describe a device you might be more comfortable thinking about: a soldering iron. All of the aforementioned appliances and tools have one important thing in common that makes them different from, say, a hair dryer. Any thoughts?

The important common factor is that the thermal resistance between the heating element and the heated medium is much lower than the thermal resistance between the medium and the ambient world. Thus, if electric current stops flowing through the heating element, the temperatures of the element and the medium will equalize long before the medium loses much of its temperature via heat radiation and conduction.

Because the resistance of all the conductors used for constructing heating elements has some temperature coefficient, you can measure the temperature of the heating element by measuring its resistance and comparing it to its resistance at, say, 25°C. This brings us neatly to the basic idea behind this project.

First, you turn on the heating element for a while. Then, switch it off and wait for the temperatures to equalize. After that, you must measure the resistance and calculate the temperature. And then do it again: switch on, switch off, measure, and so on. It’s easy to see why this approach wouldn’t work with a hair dryer. The air forced through a hair dryer moves quickly and has poor heat conductivity.

I can hear you asking the obvious questions. How difficult is it to measure the element resistance? How much does it change with temperature? Wouldn’t a simple sensor be cheaper and easier to use? It depends on the application. I will address these concerns as I describe the soldering iron example.

The schematic below shows Malik’s complete application. The power supply is the only part not shown in the schematic of the soldering station. The current source is powered
by 8 V to reduce power dissipation.

In the measurement circuit, the current source is built from an adjustable linear regulator. The current is set to a little higher than 200 mA. The main power switch Q1 is connected to an additional transistor circuit to translate the control voltages down to the 0- to 5-V range the Freescale MC68HC908QT4 microcontroller is capable of generating.

The complete application, without the power supply

The complete application, without the power supply

The MC68HC908QT4 microcontroller is an inexpensive 8-bit HC08 device housed in an eight-pin DIL package that’s easy to work with. The microcontroller is connected to an LED that indicates whether the soldering tip is below, equal to, or above the desired temperature. A potentiometer regulates the desired temperature. The remaining pieces of the circuit are two trimmers that are used to calibrate the offset and gain of the temperature regulation.

A schematic of the power supply I used isn’t shown here. I used a small, lightweight custom switch-mode power supply. However, the circuit will work equally well with a mains transformer-based power supply.

This temperature measurement application is very simple. As a result, the small amount of code for the ’HC908QT4 is little more than 700 bytes.

Download the entire CC191 article.

High-Resolution Resistive Sensing Signal Conditioner

Texas Instruments recently introduced the PGA900 high-resolution resistive sensing signal conditioner. The PGA900 enables the fast and precise 24-bit measurement of conditions such as pressure, flow, strain, or liquid levels. Its programmable core enables flexible linearization and temperature compensation for numerous resistive bridge sensing applications.TI PGA900

Key features and benefits include:

  • Fast, precise sensor signal and temperature compensation: Integrates two 24-bit ADCs to provide high-resolution signal acquisition. Low-drift voltage reference of 10 ppm/°C, maximum, enables high accuracy across the –40°C to 150°C operating temperature range.
  • Integrated 14-bit DAC: Enables highly linear analog outputs.
  • User-programmable temperature and nonlinearity compensation algorithms: Integrated ARM Cortex-M0 core allows developers to use proprietary temperature and nonlinearity compensation algorithms to differentiate their end products.
  • Simple calibration: One-wire interface allows communication, configuration and calibration through the power supply pin without using additional lines.
  • Wide input voltage allows direct connection to the power supply: Integrated power management circuitry accepts input voltages ranging from 3.3 to 30 V to simplify the design and provide reliability.

With the PGA900 evaluation module (EVM), you can to quickly and easily evaluate the device’s performance and integrated features. The PGA900EVM is available for $249. You can download PGA900 example software and the user’s guide, as well as the PSpice and TINA-TI Spice and TINA-TI models, at www.ti.com.

The PGA900 resistive sensing conditioner comes in a 6 mm × 6 mm very thin quad flat no-lead (VQFN) package. It costs $4.50 in 1,000-unit quantities.

Source: Texas Instruments

New 700-V HVICs Increases System Reliability, Shrink Board Space

Infineon Technologies recently launched a family of rugged, reliable 700-V High-Voltage ICs (HVICs) optimized for solar, power supply, uninterruptible power supplies (UPS), welding, and industrial drive applications. The 700-V offering enables designers of high-voltage power stages to simplify their designs while making them more robust.Infineon-700V-HVIC

The new IR7xxxS series of HVICs feature sink/source ratings from 60 to 2,300 mA and utilize PN junction technology. Available in half bridge and high- and low-side configurations, the new HVICs are optimized for 700-V MOSFETs and 650-V IGBTs and offer full driver capability with extremely fast switching speeds to reduce magnetics component count.

Other key features of the new devices include under-voltage lock-out protection for both channels, lower di/dt gate driver for better noise immunity. In addition, the HVICs are tolerant to negative transient voltage dv/dt, offer matched propagation delay for both channels and are 3.3- and 15-V input logic compatible.

The new IR7xxxS series is available in surface-mount (8-SOIC) packages in high volume. The lead-free devices are RoHS-compliant.

Source: Infineon

Video Decoder with MIPI-CSI2 Output Interface Supports Next-Generation SoCs

Intersil Corp. recently introduced the TW9992 analog video decoder, which features an integrated MIPI-CSI2 output interface that provides compatibility with the newest SoC processors. The decoder’s MIPI-CSI2 interface simplifies design by making it easier to interface with SoCs, while also lowering the system’s EMI profile. The TW9992 decoder takes both single-ended and differential composite video inputs from a vehicle’s backup safety camera, and is the latest addition to Intersil’s video decoder product family for automotive applications.TW9992-intersil

Designed with built-in diagnostics and superior video quality, the TW9992 addresses the biggest challenges faced by automotive video systems. For example, the decoder’s Automatic Contrast Adjustment (ACA) image enhancement feature overcomes a major challenge for backup camera systems by adapting to rapidly changing lighting conditions. ACA is able to automatically boost up or reduce the brightness/contrast of an image for greater visibility and safety.

In addition, vehicle backup cameras typically employ differential twisted pair cables that require designers to use an operational amplifier (op amp) in front of the video decoder to convert the differential signal to single-ended. The TW9992 decoder eliminates the need for an external op amp by supporting direct differential CVBS inputs, thus reducing system cost and board space. The built-in short-to-battery and short-to-ground detection capability on each differential input channel further enhances video performance and automotive system reliability.

Features and specifications:

  • NTSC/PAL 10-bit ADC analog video decoder with 4H adaptive comb filter
  • MIPI-CSI2 output interface
  • Software selectable analog input control allows for combinations of single-ended or differential CVBS
  • Advanced image enhancement features: automatic contrast adjustment, and programmable hue, brightness, saturation, contrast and sharpness
  • Output voltage: 1.8 to 3.3 V with 3.3 V tolerance
  • Low-power consumption: 100-mW typical
  • Integrated short-to-battery and short-to-ground detection tests
  • AEC-Q100 qualified

The automotive-grade TW9992 analog video decoder is available in a 32-pin wettable flank QFN package. It costs $3 in 1,000-piece quantities.

Source: Intersil Corp.

Qseven Module with Quad-core Pentium Processor with 4K Resolution

congatec AG recently announced an addition to its Qseven family. The conga-QA4 module includes the new Intel Pentium and Celeron processors based on 14-nm technology and offers increased energy savings and computing power. The optimized Intel Gen8 graphics, with up to 16 graphics execution units (EUs) and 4K (3,840 × 2,160 pixels) resolution, create a high-quality visual experience.conga-QA4_congatec

The module comes in three different processor versions (Intel Braswell) for high scalability. They range from the entry-level, dual-core Intel Celeron N3050 with 1.6/2.08 GHz to the quad-core Intel Pentium N3700 with 1.6/2.4 GHz, each with a power consumption of 4 W for standard applications (Scenario Design Power, SDP).

With the new conga-QA4 module, you can upgrade Qseven applications to the latest processor technology quickly and easily. The Qseven module comes with up to 8-GB, dual-channel DDR3L memory and up to 64-GB eMMC 5.0 for mass storage. The enhanced integrated Intel Gen8 graphics supports DirectX 11.1, OpenGL 4.2, and OpenCL 1.2. The new hardware-accelerated video decoding of H.265/HEVC requires a 50% lower data rate compared to H.264/AVC, so you can stream 4K videos in real time.

You can use the conga-QA4 module for a variety of retail, digital signage, and medical applications, or whenever you need high-performance graphics, outstanding computing power, and passive cooling. With native USB 3.0 support, the conga-QA4 module provides fast data transmission despite low power draw. Six USB 2.0 ports are available, one of which is executed as USB 3.0 SuperSpeed.

Three PCI Express 2.0 lanes and two SATA 3.0 ports with up to 6 Gb/s allow fast and flexible system extensions. The Intel I211 Gigabit Ethernet Controller offers the best software compatibility, while I2C bus, LPC bus for easy integration of legacy I/O interfaces, and Intel High Definition Audio with an 8-channel sound card round off the feature set.

Source: cognatec

Electrical Engineering Crossword (Issue 299)

The answers to Circuit Cellar’s June 2015 electrical engineering crossword puzzle are now available. 299-Grid-(key)

Across

  1. CURRENT—Eddy
  2. LUMEN—A lux is one per square meter
  3. KILBY—Nobel prize for physics in 2000
  4. EXABIT—1,000,000,000,000,000,000 bits
  5. ARITY—Programming term for the number of arguments or operands a function or operator takes
  6. PION—Pi meson
  7. STATOHM—Five of these equals approximately 4.5 × 1012 ?
  8. LIN—Bus system for automotive networks
  9. PATCH—Supplemental software as a fix
  10. BITERROR—Incorrect reading of a bit [2 words]

Down

  1. XTAL—Crystal
  2. MINIMA—Lowest point in the domain of a function
  3. FLEMING—Electrical engineer (1849–1945) who designed the thermionic valve
  4. HERTZ—Cycles/second
  5. BAT—BATCH FILE
  6. TRIVALENT—A valence of 3
  7. ANECHOIC—Absent of sound
  8. FILTER—Blocks or allows to pass
  9. GND—Ground
  10. ACID—pH < 7

Electrical Engineering Crossword (Issue 298)

The answers to Circuit Cellar’s May 2015 electrical engineering crossword puzzle are now available.298-crossword-grid-(key)

Across

  1. ATTOSECOND—10-18 of a second
  2. SHIELDING—A barrier of conductive or magnetic matter
  3. HAPTIC—Relating to touch
  4. BEAMFORMING—Signal processing for sensor arrays
  5. SCRIPT—A sequence, instructions
  6. TRIMPOT—A small potentiometer used for making preset adjustments in a circuit
  7. LUX—Light intensity
  8. DEMAGNETIZE—Degauss
  9. XENON—Xe
  10. COAXIAL—Sharing the same axis
  11. DECIBEL—0.1 bel

Down

  1. CENTIMETER—0.3937 inches
  2. CATWHISKER—Flexible sharp wire that connects to a semiconductor crystal’s surface [two words]
  3. FEMTO—0.000000000000001
  4. SUBSONIC—Less than 15 Hz
  5. IMPULSE—An abrupt burst of signal energy
  6. ALTERNATOR—Mechanically driven generator of AC electricity
  7. HOMEBREW—DIY, homemade
  8. AMPHOUR—Current flow over time
  9. BAUD—200 bits per second = 200 what?

Electrical Engineering Crossword (Issue 297)

The answers to Circuit Cellar’s April 2015 electrical engineering crossword puzzle are now available.297-puzzle-(key)

Across

  1. RELAY—A switch actuated by another electrical signal
  2. OFFSET—A permanent deviation from the design center of any device or circuit
  3. DIP—A component for a PCB use that has pins arranged in two parallel rows
  4. DECIBEL—1/10th of a Bel
  5. ENCODE—Convert analog information to digital data
  6. DAMP—Suppress a resonance by absorbing stored energy through the application of mechanical or electrical friction
  7. DELIMIT—To define or set limits on the boundaries of something
  8. LOOP—Two electrically conductive paths carrying the same signal
  9. CHARGE—State of having a stored excess or deficiency of electrons, which imparts electrostatic polarity to a capacitor or object
  10. DECIMALS—10.1 mal equals 10 what?
  11. OVERSHOOT—The tendency for a rapidly increasing or decreasing electrical impulse to exceed momentarily its actual peak level

Down

  1. CENTIMETER—0.3937 inches
  2. COAXIAL—Sharing the same axis
  3. FIELD—A volume of space through which any radiated energy is distributed
  4. DETECTOR—A circuit that extracts the modulations from a carrier
  5. CELL—An electrochemical unit for producing DC electricity
  6. CARDIOID—Heart-shaped
  7. PATCH—Reroute a signal to a different circuit
  8. JOULE—An “erg” is a unit of work equal to 1–7 of these
  9. FRAME—A digital signal comprises a series of these

Electrical Engineering Crossword (Issue 296)

The answers to Circuit Cellar’s March 2015 electrical engineering crossword puzzle are now available. 296-grid-(key)Across

2. HUM—Field of 60 or 120 Hz magnetic or electrostatic energy
5. SWEEP—Scan of a range of frequencies
6. WIREWOUND—WW
13. POTENTIOMETER—Pot
14. NANO—Prefix that divides a unit by a billion
15. ISOTROPIC—Exhibiting the same physical properties in all directions
17. MICROMETER—One millionth of a meter
18. INCREMENT—To change in value by a discrete step
19. INTERFERENCE—RFI, EMI
20. MULTIMETER—Test instrument that can make several different measurements

Down

1. QUALITYCONTROL—QC (two words)
3. FLUX—A field of radiated energy
4. FERROMAGNETIC—Magnetizable substance based on iron
7. DIFFRACTION—Bending of energy waves as they move around or through an obstacle
8. JUNCTION—Any connection between two electrical conductors
9. CLIPPING—Slicing off of signal peaks
10. COMMON—Conductor shared by various circuits
11. SUBSONIC—Slower than the speed of sound
12. DECODE—Convert a digital signal back into an analog signal
16. CAPACITANCE—Measured in fractions of a farad

Electrical Engineering Crossword (Issue 295)

The answers to Circuit Cellar’s February 2015 electrical engineering crossword puzzle are now available.295puzzle

Across

2. COMMON—A connection or conductor that a number of circuits share
5. TRIODE—Comprises a cathode, plate, and control grid
6. SKINEFFECT—The tendency for electrons at high frequencies to travel along the surface of a conductor [two words]
7. IBM—Big Blue
9. PASCAL—Pa
10. SHEATH—Tube that protects a bundle of wires
15. AVOGADRO—6.0221415 × 1023 atoms/mole
17. CONDENSER—A capacitor
18. MEGA—M
19. QFACTOR—Measures the damping of resonator modes

Down

1. BIDIRECTIONAL—Figure-8
3. OSCILLATION—Self-sustaining generation of a continuous electrical signal
4. SELFBIAS—Cathode bias [two words]
8. MANCHESTER—In this code, common in telecommunications, each bit of data is represented by at least one voltage level transition.
11. WIREWOUND—WW
12. TANGENT—Straight line that touches a circuit a single point
13. MALE—Hot signal connector
14. FERROUS—Containing iron
16. OHMSLAW—R = V/I [two words]
17. CBAR—0.01 bar

New Home Control & IoT Wi-Fi Module

MSC Technologies, a business group of Avnet Electronics, recently introduced the new WLAN-Module HDG820 for 802.11.b/g/n networks, designed by H&D Wireless AB (Sweden). The solution incorporates a complete IP protocol set running on an internal ARM Cortex core and is an ideal platform for advanced smart-home, IoT and M2M applications over Wi-Fi.MSC-H-and-D-WirelessWeb

H&D Wireless AB specializes in world class Wi-Fi solutions, combining a deep knowledge of embedded wireless systems, silicon design and system software for cloud services and mobile phone apps. The company’s range of WLAN is deemed best in class in terms of size, power consumption in all modes, transmit/receive range, data transfer speed and cost. Wi-Fi solutions from H&D Wireless are supported on leading MCU platforms allowing easy access to the Internet as well as data and audio for consumer electronics.

The new HDG820 SiP-Module from H&D Wireless includes the Controller, WLAN transceiver and Memory and is delivered in an extremely small SMD package of 8 × 8 × 1.2 mm3. It can be controlled via UART / SPI which is also the interface for data transfer. With a power consumption of max. 220 mA and 250 µA in Sleep mode and an RF performance of +17 dBm in Tx and –96 dBm in Rx, it fulfills all requirements for typical building and home applications. An extended temperature of –40 to +85°C also makes it an ideal platform for Wi-Fi enabled sensors in industrial applications.

The HDG820 module is pre-certified for CE and FCC and of course Wi-Fi certified. In addition to its compact size only very few components need to be added to the BOM list (e.g., antenna and capacitors), allowing for extremely competitive new designs with all the benefits of WLAN solutions.

Even more interesting is the list of supported software features. Protocols like TCP/IP, HTTP and more as well as features like Soft-Access Point, Wi-Fi Direct and also security features like WPA are available and fully integrated. The Pico oWL API is designed to be compiled and executed on multiple processor platforms from 8 bit to 32bit and makes configuration really easy, also enabling full control of the module. H&D Wireless even supplies a Linux design environment.

Furthermore the Griffin Software, also delivered by H&D Wireless, supports full cloud computing capabilities and easy app integration with several reference designs available. All software is available for free. Development kits, demo applications and of course the modules itself are available at MSC Technologies in Europe and Avnet Electronics worldwide.

Source: www.hd-wireless.sewww.msc-technologies.eu

Via audioXpress

High-Side Current/Power Sensor

Microchip Technology recently introduced the PAC1921, a high-side current sensor with both a digital output, as well as a configurable analog output that can present power, current or voltage over the single output pin. Simultaneously, all power related output values are also available over the 2-Wire digital bus, which is compatible with I2C. The PAC1921 is available in a 10-lead 3 × 3 mm VDFN package. It was designed with the 2-Wire bus to maximize data and diagnostic reporting, while having the analog output to minimize data latency. The analog output can also be adjusted for use with 3-, 2-, 1.5-, or 1-V microcontroller inputs.Microchip PAC1921 Eval

The PAC1921 is ideal for networking, power-distribution, power-supply, computing and industrial-automation applications that cannot allow for latency when performing high-speed power management. A 39-bit accumulation register and 128 times gain configuration make this device ideal for both heavy and light system-load power measurement, from 0 to 32 V. It has the ability to integrate more than two seconds of power-consumption data. Additionally, the PAC1921 has a READ/INT pin for host control of the measurement period; and this pin can be used to synchronize readings of multiple devices.

The PAC1921 is supported by Microchip’s $64.99 PAC1921 High-Side Power and Current Monitor Evaluation Board (ADM00592). The PAC1921 is available for sampling and volume production, in a 10-lead 3 × 3 mm VDFN package, starting at $1.18 each in 5,000-unit quantities.

Source: Microchip Technology

Precision Set & Readback PMBus-Compatible µModule Regulator

Linear Technology recently announced the LTM4675 dual 9-A or single 18-A, µModule (micromodule) step-down DC/DC regulator with PMBus serial digital interface. It comes in a 11.9 mm × 16 mm × 3.51 mm BGA package. The I²C-based interface enables you to manage a system’s power condition and consumption. Calibrated and guaranteed from –40°C to 125°C, output DC voltage accuracy is ±0.5% over line and load regulation, and load current readback accuracy is ±2.5% maximum.Linear 4675

The LTM4675—which features EEPROM, power MOSFETs, inductors and supporting components—dual analog control loops and precision mixed-signal circuitry. It is drop-in pin-compatible with the larger package (16 mm × 16 mm BGA) higher power dual 13A LTM4676A, eliminating layout changes so that system designers can easily switch between the devices during the prototype phase. This eliminates redesign of power circuits if power requirements change during board prototyping. The LTM4675 has applications in optical transport systems, datacom and telecom switches and routers, industrial test equipment, robotics, RAID and enterprise systems where energy costs, cooling and maintenance are critical and must be continuously and precisely measured.

The LTM4675 operates from a 4.5-to-17-V input supply and steps down VIN to two outputs ranging from 0.5 to 5.5 V. Two channels can current share to provide up to 18 A (i.e., 9 A + 9 A as one output). Power-up turn-on time is 70 ms. To evaluate the performance of the LTM4675, the free LTpowerPlay GUI-based development system is available for download, and a USB-to-PMBus converter and demo kit are available. With ±0.5% maximum DC output error over temperature, ±2.5% current readback accuracy, integrated 16-bit delta-sigma ADC and EEPROM, the LTM4675 combines best-in-class analog switching regulator performance with precision mixed-signal data acquisition. At start-up, output voltages, switching frequency and channel phase angle assignments can be set by pin-strapping resistors.

The LTM4675 internal operating temperature range is from –40°C to 125°C.  It costs $24 in 1,000-piece units.

Source: Linear Technology

High-Speed, Conditioned Measurements with Channel-to-Channel Isolation

Measurement Computing Corp. recently announced the release of the SC-1608 Series of USB and Ethernet data acquisition devices. The series features analog signal conditioning that enables you to measure voltage, thermocouple, RTD, strain, frequency, and current. Isolated analog output and solid-state relays make it a good solution for systems requiring flexible conditioning and low cost per channel.MCC-SC-1608-Series

There are four devices in the SC-1608 Series with sample rates up to 500 ksps. Each device accommodates up to eight 8B isolated analog signal conditioning modules and eight solid state relay modules. Up to two isolated analog outputs are available on some models. Signal conditioning modules are sold separately.

Microsoft Windows software options for the SC-1608 include DAQami and TracerDAQ to display and log data, along with comprehensive support for C, C++, C#, Visual Basic, and Visual Basic .NET. Support is also included for DASYLab and NI LabVIEW. UL for Android provides programming support for Android devices. Open-source Linux drivers are also available.

The SC-1608 Series costs $999.

Source: Measurement Computing Corp.