SBOS079C March 1999 – February 2023 OPA2277 , OPA277 , OPA4277
PRODUCTION DATA
- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
- 8 Application and Implementation
- 9 Device and Documentation Support
- 10Mechanical, Packaging, and Orderable Information
Package Options
Refer to the PDF data sheet for device specific package drawings
Mechanical Data (Package|Pins)
- D|8
- DRM|8
- P|8
Thermal pad, mechanical data (Package|Pins)
- DRM|8
Orderable Information
7.3.4 Input Bias Current Cancellation
The input stage base current of the OPAx277 series is internally compensated with an equal and opposite cancellation circuit. 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, a bias current cancellation resistor is not necessary, as is often done with other operational amplifiers. #SBOS0799737 shows a conventional op amp with external bias current cancellation resistor compared to the OPA277 with no external bias current cancellation resistor. A resistor added to cancel input bias current errors can actually increase offset voltage and noise.
Figure 7-3 Input Bias Current Cancellation