INA351A is a G = 10 instrumentation amplifier with configurable reference amplifier designed to provide an integrated, small size, cost-effective solution for applications employing discrete implementation of INA using commodity amplifiers and resistors. This integrated instrumentation amplifier is built using four operational amplifiers and seven precision matched integrated resistors. With 86dB minimum CMRR and 0.1% maximum gain error, INA351A is suitable to be used directly in sub 10-bit systems without any external calibration. Additional calibration of offset and gain error at a system level can further improve system resolution and accuracy, enabling use in 12-bit to 14-bit precision applications.

INA351A has a configurable reference amplifier with external input and output pins. This reference amplifier's output is connected to the 60-kΩ internal resistor so that any reference voltage on the amplifier input that sets the output common mode of the INA could be buffered. This buffered output voltage is available externally and could be used to bias subsequent amplifier stages.

More importantly, the reference amplifier enables DC error calibration when configured in a servo loop. When the INA input signal is at a slightly higher frequency than DC, the servo amplifier can enable external calibration of total DC errors (offset, drift etc.) at the INA output leading to a overall better DC precision. The INA351A in calibration loop is well suited for medical applications where the low-frequency signals like ECG, EEG, EMG are to be amplified with relatively lower noise and lesser DC errors. It is also suitable for use in industrial applications in higher frequency pressure transducers and lock in amplifier designs.

One of the key features of INA351A is that the device does not need any external resistors to set the gain. Often these external resistors require tighter tolerance and careful routing, which adds to system complexity and cost. The device is highly suitable for voltage sensing in space-constrained applications such as patient monitoring, sleep diagnostics, electronic hospital beds, and blood glucose monitoring. INA351A can enable these systems to reduce their overall size and cost while providing optimal performance.