1.3 Troubleshooting Tips: Op Amps - Power Supply Rejection Ratio

Understanding how to verify datasheet specifications such as power supply rejection ratio (change in offset versus change in power supply voltage) is critical to the application troubleshooting and debugging process. In this training the false summing junction circuit is utilized to demonstrate how to determine the PSRR of a linear amplifier. At the system level an offset anomaly versus power supply voltage may result in the following signatures:

• Increased or decreased output voltage compared to the nominal

• Anomalous reading observed by ADC

• Unexpected sensor reading