The gain (G) is set by connecting a single external resistor, R_G, between pins 1 and 8:

Commonly used gains and resistor values are shown in Figure 9-1.

The 50-kΩ term in Equation 1 and the 49.4-kΩ term in Equation 2 come from the sum of the two internal feedback resistors of A₁ and A₂. These on-chip metal film resistors are laser trimmed to accurate, absolute values. The accuracy and temperature coefficient of these internal resistors are included in the gain accuracy and drift specifications in the Electrical Characteristics table.

The stability and temperature drift of the external gain setting resistor, R_G, also affects gain. The contribution of R_G to gain accuracy and drift can be directly inferred from Equation 1 and Equation 2. Low resistor values required for high gain can make wiring resistance important. Sockets add to the wiring resistance, which contributes additional gain error (possibly an unstable gain error) in gains of approximately 100 or greater.