The INA132 is laser trimmed for low offset voltage and drift. Most applications require no external offset adjustment. Figure 6-2 shows an optional circuit for trimming the output offset voltage. The output is referred to the output reference terminal (pin 1), which is normally grounded. A voltage applied to the Ref terminal is summed with the output signal, and can be used to null offset voltage. Verify that the source impedance of a signal applied to the Ref terminal is less than 8Ω to maintain good common-mode rejection. To maintain low impedance at the Ref terminal, the trim voltage can be buffered with an op amp, such as the OPA177.

Figure 6-2 Offset Adjustment.