ADI amplifier provides programmable gain

The AD628 common-mode difference amplifier from Analog Devices Inc. is among the first to include programmable gain, according to the company.

The amp can be adjusted by an external resistor to provide a gain range from 0.1 to 1,000. It can accept 1140V inputs and drive the latest generation of single-supply ADC or sigma-delta converters.

The AD628 targets industrial applications that accept inputs from various sensors, as well as motor drive interfaces and controllers, high-voltage current sensors, and sensor-signal conditioning. Its high common-mode input impedance also suits the device for high-voltage measurements across a shunt resistor, the company claimed.

A dedicated output amplifier allows designers to attenuate, level-shift, filter, and scale the AD628's output signal. Those functions were previously available only with discrete components. The device can convert a bipolar input signal to a unipolar output. It can filter out noise by adding a single external capacitor.

The AD628 operates from single or dual supplies from 5V to 15V and provides 80dB of common-mode rejection from 0Hz to 500Hz minimum. It's available in an eight-lead SOIC or microSOIC and is rated for -400C to 850C industrial temperatures. Samples are available now. At $3.45 in quantities of 1,000, the device is expected to be less than half the cost of a discrete solution.

EE Times