Common-Mode Differential Amp Integrates Programmable Gain

The AD628 common-mode differential amplifier is said to be the first such device to provide programmable gain. Using an external resistor, the amplifier can be set for a gain range from 0.1 to 1,000. With an input voltage range of ±140V, the chip is capable of driving the latest generation of single-supply A/D converters and sigma-delta converters. A dedicated output amplifier allows users to attenuate, level shift, filter, and scale the output, eliminating the need for external components. The device can also convert a bipolar input to a unipolar output. Other features include a common-mode rejection of 80 dB from dc to 500 Hz minimum, operation from single or dual power supplies from 5V to 15V, and an operating temperature range from -40°C to 85°C. Available in eight-lead SOIC and microSOIC packages, the AD628 common-mode differential amplifier costs $3.45 each/1,000. ANALOG DEVICES INC., Wilmington, MA. (800) 262-5643.