Low-power (110 µA) instrumentation amplifier with integrated reference amp to enable calibration

INA351A is a fixed gain of 10 instrumentation amplifier with a configurable reference amplifier in a small package. This instrumentation amp (INA) is built with precision-matched resistors to achieve excellent CMRR and gain error performance in a small, low-cost form factor. This makes INA351A a great solution to replace discrete INA implementations to achieve higher performance and more compact designs with minimal impact to bill of materials (BOM) costs.

The integrated, configurable reference amplifier can be used as a buffer for external use or as part of a closed-loop calibration circuit to achieve better DC precision. The closed-loop calibration can be accomplished by implementing a servo loop amplifier to calibrate DC errors from sensors (like offset, offset drift and so forth) at the INA output when the INA input signal is at a slightly higher frequency than DC depending on the application.

INA351A achieves 86 dB of minimum CMRR, an accurate 0.1% of maximum gain error and only consumes a maximum of 135 µA quiescent current at room temperature. The INA can directly drive sub-1 kHz, 10-bit to 14-bit, delta-sigma analog-to-digital converters (ADC) without an ADC driver, making it a great choice for portable, battery-powered medical applications like electrocardiograms or wearable health monitors.