MSPM0L1305: Need clarification on using internal OPA

Kenley

Intellectual 1935 points

Part Number: MSPM0L1305
Other Parts Discussed in Thread: SYSCONFIG

Hi,

My customer is considering to input the signal from shunt resistor to internal OPA and amplify it to directly send to internal ADC.

In this case, i think OPA buffer mode is the right choice. But due to low value of the shunt resistor voltage, i think we need to amplify it gain around 10~20.

Is this possible to do it in buffer mode ?

If yes, do i just change the value of the gain in the opa pre-set configuration of sysconfig to non-inverting 16x? Any action required on the software beside enabling the OPA?

Best regards,

Kenley

3 months ago

0 Pengfei Xie 3 months ago

TI__Genius 12315 points

Hi Kenley,

The OPA buffer mode has no amplify function, in this mode OPA just works as a buffer to give a larger input impedance for ADC.

The 10~20 amplify times could be achieved by OPA, and you could start from SDK opa_non_inverting_pga example and test on launchpad for your requirement.

0 Kenley 3 months ago in reply to Pengfei Xie

TI__Intellectual 1935 points

Hi Pengfei,

What should i do to set the output of the OPA to directly send the signal to ADCx?

Best regards,

Kenley

0 Pengfei Xie 3 months ago in reply to Kenley

TI__Genius 12315 points

Hi Kenley,

There is internal connection between OPA output and ADC certain input channels. So what we need to do is just configure ADC and select correct ADC channel for OPA input.

You could refer to Table 8-7. ADC0 Channel Mapping of MSPM0L130x Mixed-Signal Microcontrollers datasheet (Rev. D) for ADC channel details.

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MSPM0L1305: Need clarification on using internal OPA