The MAX4174/MAX4175/MAX4274/MAX4275 GainAmp family combines a low-cost rail-to-rail op amp with precision internal gain-setting resistors and V_CC/2 biasing. Factory-trimmed on-chip resistors decrease design size, cost, and layout, and provide 0.1% gain accuracy. Fixed inverting gains from -0.25V/V to -100V/V or noninverting gains from +1.25V/V to +101V/V are available. These devices operate from a single +2.5V to +5.5V supply and consume only 300µA. GainAmp amplifiers are optimally compensated for each gain version, achieving exceptional GBW products up to 23MHz (A_V = +25V/V to +101V/V). High-voltage fault protection withstands µ17V at either input without excessive current draw.

Three versions are available in this amplifier family: single/dual/quad open-loop, unity-gain stable (MAX4281/MAX4282/MAX4284); single/dual fixed gain (MAX4174/MAX4274); and single/dual fixed gain plus internal V_CC/2 bias at the noninverting input (MAX4175/MAX4275), which simplifies input biasing in single-supply designs. The input common-mode voltage range of the open-loop amplifiers extends from 150mV below the negative supply to within 1.2V of the positive supply. The outputs can swing rail-to-rail and drive a 1kΩ load while maintaining excellent DC accuracy. The amplifier is stable for capacitive loads up to 470pF.