ZHCSSH3A September 2000 – September 2023 OPA177
PRODUCTION DATA
The input stage base current of the OPA177 is internally compensated with an equal and opposite cancellation current. The resulting input bias current is the difference between the input stage base current and the cancellation current. This residual input bias current can be positive or negative.
When the bias current is canceled in this manner, the input bias current and input offset current are approximately the same magnitude. As a result, there is no need to balance the dc resistance seen at the two input pins (Figure 7-2 and Figure 7-3). A resistor added to balance the input resistances can actually increase offset and noise.