STMicroelectronics’ LIS302DLH, a three-axis digital micro-electro-mechanical-systems (MEMS) accelerometer, is a 16-bit device measuring 0.75 mm high. According to ST, the product partakes in its Piccolo MEMS family’s 3- by 5-mm footprint and therefore is suitable for space-saving designs.

The LS8297, LS8297CT, and LS8397 stepper motor-controller ICs from LSI Computer Systems Inc. are designed to replace the L297 in all applications while providing additional features. They offer half-step and full-step sequences in both normal drive and wave-drive modes similar to the L297.

Designed for power- and space-constrained applications, the MAX9943 and MAX9944 high-voltage operational amplifiers from Maxim Integrated Products deliver superior precision in sensor signal conditioning, high-performance industrial instrumentation, and loop-powered systems, according to the company. Also, Maxim’s MAX9945 suits portable medical and industrial applications that require low-noise analog front ends.

The TSV6xx families of precision operational amplifiers from STMicroelectronics are designed for low-power and portable products with power-saving features like high-speed performance at low supply current, operation from a 1.5-V supply, and device-shutdown capability.

Engineers seldom have to design with discrete components anymore. Integrated ADCs, DACs, high-speed amplifiers, and switch capacitor ICs are now readily available. The most truly amazing advances, however, have been in digital design. The shortage of logic chip designers and the expense of design has led to development along two different avenues: microprocessors and programmable logic. Now, though, these avenues are merging.

HI BOB, I read your response to Arthur Williams in the April 23 column (“Bob’s Mailbox”). The answer as to whether or not to remove the ground plane underneath inductors is: it depends. If the inductors are cans or toroids, it does not matter as the fields are contained inside the inductor. If the inductors are air wound or chip inductors, it might be best to try...

The MCP65X 50-MHz rail-to-rail operational amplifiers from Microchip Technology include an on-chip “mCal” calibration circuit that calibrates offset voltage at powerup or on-command. An internal power on-reset detector or a signal on an external pin initiates calibration. Self-calibration provides a lower initial voltage offset than conventional op amps, along with a means to continually control drift over time and temperature, Microchip says (...

High-reliability oscillator design for satellite systems poses many challenges to the engineering community. The custom nature of the design efforts as well as the quality requirements tend to lead to large, complex specifications that drive cost, design cycle time, and overall product lead time. Materials utilized in design and construction are also limited by environmental constraints such as outgassing, radiation, the use of pure tin, and shock/vibration...

Enter “motion control” or “motor control” into your favorite search engine, and you’ll be rewarded with links to an ad-hoc encyclopedia of solid design information. Freescale’s site (www.freescale.com/webapp/sps/site/overview.jsp?nodeId=02M0zpbnQXGM0zpqCKS2&tid=tMCdr) is broad, deep, and far more than a product selection guide—which it...

Cars are exciting, and appliances are boring, right? That depends. While you can’t take an air conditioner for test drives on a frozen lake to evaluate its dynamic response to regenerative braking in slippery conditions, as Greg Solberg did with the Tesla Roadster, there can still be challenges. For example, cultural and economic differences in regional markets for white goods influence motor-control design. On the cultural side, to cite one case, China and Japan present a...

Delta VBE-based (VBE) thermometry1,2,3,4 is based on this classic bipolar junction I/V/T relationship: For an ideal transistor, the VBE corresponding to ratiometric change in collector current (I2 / I1) is exactly proportional to absolute temperature: VBE = 198.4 µV * °K * LOG10(I2 / I1). Because cheap, common, and robust small-signal transistors conform closely to the ideal model, circuits that exploit the “PTAT (Proportional...

This charge-pump voltagecontrolled oscillator (VCO) has a number of neat features: single positive power-supply operation, positive VCO reference voltage, fast response, high linearity, temperature compensation, and open collector output. Seldom are all of these features present simultaneously. Though the component count is relatively high compared to commercially available devices, cost is low because all components are garden variety. Central...

This circuit design for a current-mode analog multiplier/ divider is based on current-controlled conveyors (CCCII) and a second-generation current conveyor (CCII). No passive components are used. Analog multipliers and dividers are important building blocks in signal processing and are widely used in modulation systems. Also, for the same two inputs, the multiplier changes to a squaring circuit, which provides the energy content of the signal. ...

The use of a copper winding as a temperature sensor is not new. The traditional technique is to disconnect the ac power and the load and to quickly make the measurement using an ohmmeter. But the circuit presented here goes further. It can make the measurement in-circuit and in real time. The resistance value is derived by injecting a small dc current into the monitored winding and measuring the resulting dc potential. However, care must be taken to avoid...

Thermistors are extremely nonlinear devices. Because of the limitations of the mathematical model used, the devices’ ultimate accuracy is hardly ever fully realized due to the extra computational burden required to calculate the temperature from an accurate resistance reading. Fortunately, a minor modification to any thermistor equation will provide a worthwhile improvement in overall accuracy. This article shows how an improved mathematical model...