The MAX4208/MAX4209 ultra-low offset and drift instrumentation amplifiers feature exceptional precision specifications, low power consumption, rail-to-rail output, excellent gain-bandwidth product, and buffered REFIN/MODE input in a very small μMAX? package. These devices use a patented? spread-spectrum, autozeroing technique that constantly measures and corrects the input offset, eliminating drift over time and temperature and the effect of 1/f noise. This technique achieves less than 20μV offset voltage, allows ground-sensing capability, provides ultra-low CMOS input bias current and increased common-mode rejection performance.

The MAX4208/MAX4209 provide high-impedance inputs optimized for small-signal differential voltages (±100mV). All devices provide a gain-bandwidth product of 750kHz.

The MAX4208 provides an adjustable gain with two external resistors or unity gain with FB connected to OUT. The MAX4209 is available in fixed gains of 10V/V, 100V/V, or 1000V/V (suffixed T, H, and K) with ±0.03% (typ) accuracy. Both devices include a reference input (REF) to level-shift the output, allowing for bipolar signals in single-supply applications. In both devices, REFIN/MODE is an input to a precision unity-gain buffer, which sets the REF voltage to level-shift the output. The internal REF buffer allows the reference to be set by a simple resistive divider or an ADC reference without any loading error.

The MAX4208/MAX4209 operate with a 2.85V to 5.5V single-supply voltage and consume only 750μA of quiescent current (when the internal buffer is off) and only 1.4μA in shutdown mode. These amplifiers also operate with ±2.5V dual supplies with REF connected to ground and REFIN/MODE to V_SS. The MAX4208/MAX4209 are available in space-saving 8-pin μMAX packages and are specified over the automotive operating temperature range (-40°C to +125°C).