1 Introduction

Since the common-mode input range is high (±200V INA117 and ±275V INA149), it makes sense that some designers would also like to use these part for differential inputs greater than ±10V and ±13.5V. Figure 1 shows the recommended circuit for the INA117. Adding resistors to the input may seem simpler, but there are some problems with that approach.

Figure 1. INA117 with Increased Differential Input Range