TMS320F28335: How to deal with ADCREFIN pin if internal reference source selected

Xiaobing (Eric)

Part Number: TMS320F28335

Hi All,

I reviewed TMS320F28335 datasheet and found the "ADCREFIN" is connect to analog ground if internal reference source is used (http://www.ti.com/lit/ds/symlink/tms320f28335.pdf, P127), BUT TMS320x2833x Analog-to-Digital Converter (ADC) Module Reference Guide mentioned "If the internal reference option is chosen, the ADCREFIN pin can be left connected to the selected source, left floating, or grounded" (http://www.ti.com/lit/ug/spru812a/spru812a.pdf, P30).

I would like to know how to deal with ADCREFIN pin if internal reference source is used? what differences if ADCREFIN connect to grounded or floating? Any system levels accuracy/reliability concerns? Pls advices. Tks.

BR,

Xiaobing (Eric)

over 5 years ago

0 tlee over 5 years ago

TI__Guru 62975 points

Eric,

When the internal reference is used, the ADCREFIN pin is functionally isolated so it can be handled using any of the methods that you read from the Reference Guide without notable differences in outcome. Some companies have design practices that are difficult to meet when presented with multiple open-ended options for handling unused pins. Therefore, the datasheet provides a singular recommendation to connect the ADCREFIN pin to analog ground if it is not used. If you are in a similar situation, it would make sense to follow the datasheet recommendation.

-Tommy

0 Xiaobing (Eric) over 5 years ago in reply to tlee

Intellectual 895 points

Tks, Tommy~

0 tlee over 5 years ago in reply to Xiaobing (Eric)

TI__Guru 62975 points

Glad to help!

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TMS320F28335: How to deal with ADCREFIN pin if internal reference source selected