Hi TI,
Please contact us regarding PGA281AIPWR IC
-. I would like to know what VOCM Pin role is.
-. When connected to VOCM Pin GND, output voltage is measured with EF (ERR) Hi.
* Contents of IC input voltage
- VSP: 15V
- VSN: -15V
- VSOP: 5V
- VOCM: 0V
- DVDD: 5V
I would like to reply to the above information.
Hello,
The role of the VOCM pin is to set the output common-mode voltage. Since the PGA281 output stage is floating with respect to the input, you have the ability to set the output common-mode voltage to whatever works best for your application.
You can consider the output common-mode voltage to be the DC bias set as the "center" or "middle" voltage around which the output pins VOP and VON will swing. Usually VOCM is set to mid-supply, or (VSOP - VSON)/2. Please see the figure below copied from the PGA281 data sheet.
There are several possibilities why the EF pin is high, as discussed in the "Error Indicators" section of the PGA281 data sheet. The most likely is that VOCM is set too low, so the PGA281 output stage is clipping to the supply rail. Try increasing VOCM to +2.5V, the mid-supply point of the output stage, and see if the error flag resets.
Best regards,
Ian Williams
Applications Engineer
Precision Amplifiers
