1 Features

• Fixed gain of 10V/V instrumentation amp with

configurable reference amp

• INA performance for 10-bit to 14-bit systems

– CMRR: 95 dB (typical)

– Gain error: 0.015 (typical)

– Bandwidth: 100 kHz (typical)

• Reference amp can be used for:

– External DC error calibration with servo loop

– Providing buffered voltage of external circuits

– Filtering or adjustment of reference voltage

• Ultra-small package option (2mm x 2mm)

• Drives 1 nF with under 10 overshoot (typical)

• Optimized quiescent current: 110 μA (typical)

• Supply range: 1.8 V (±0.9 V) to 5.5 V (±2.75 V)

• Specified temperature range: –40°C to 125°C

2 Applications

• Electrocardiogram

• Pressure transmitter

• Weigh scale

• Flow transmitter

• Wearable fitness and activity monitor

• Blood glucose monitor

• Temperature sensing with RTD

3 Description

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, lowcost

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.