MSP430F477: Input offset voltage of PGA in SD16_A

Keigo Ishii

Part Number: MSP430F477

Hi,

Please let me know the following question.

What the value is the input offset voltage of PGA in SD16_A?
I believe that PGA in SD16_A should have input offset voltage as well as general Op Amps.

Best regards,
Keigo Ishii

over 7 years ago

0 Ryan Brown1 over 7 years ago

TI__Guru**** 206257 points

Hi Keigo,

The operational amplifier offset must be found by setting the OAxCAL bit and measuring the voltage between the negative and positive SD16_A. This value can then be incorporated into later measurement results to compensate for the amplifier offset. Please refer to Section 22.4.6 and Figure 22-13 of the User's Guide (SLAU056) for more information: www.ti.com/.../slau056l.pdf

Regards,
Ryan

0 Keigo Ishii over 7 years ago in reply to Ryan Brown1

Intellectual 820 points

Hi Ryan,

Thank you for your reply.
What I want to know is about PGA in SD16_A, not OA.
It's red circled in the picture below.

Best regards,
Keigo Ishii

0 Ryan Brown1 over 7 years ago in reply to Keigo Ishii

TI__Guru**** 206257 points

My mistake Keigo, in this case you would set the SD16INCHx bits to 111b (to short the differential pair input, see the SD16INCTLx register description in the User's Guide for more information) and perform a SD16 measurement. The result can then be analyzed in accordance with the process previously explained.

Regards,
Ryan

0 Keigo Ishii over 7 years ago in reply to Ryan Brown1

Intellectual 820 points

Hi Ryan,
I got it, Thank you for your answer!
Best regards,
Keigo Ishii

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MSP430F477: Input offset voltage of PGA in SD16_A