TMS320F28069: VREFHI treatment when the internal reference is configured

Hitoshi Sugawara

Hi Experts,

Please let me know how VREFHI terminate if the internal reference is configured?
Is it OK to leave it open?

Thank you very much for your kind check.
Best regards,
HItoshi

over 7 years ago

0 Hareesh Janakiraman over 7 years ago

TI__Guru* 95315 points

Sugawara-san,
Please check page 91 of SPRS698G (ADC Connections if the ADC is Not Used).

0 Hitoshi Sugawara over 7 years ago in reply to Hareesh Janakiraman

TI__Mastermind 21120 points

Hi Hareesh,
I am using the ADC with the internal reference.
There seems no explanation of VREFHI on page 91.
I believe that VREFHI should be connected to Vdd, Ground or open.

Thank you very much for the termination.
Best regards,
Hitoshi

0 Hareesh Janakiraman over 7 years ago in reply to Hitoshi Sugawara

TI__Guru* 95315 points

Sugawara-san,
Page 91 refers to the situation when ADC is not used, not when internal reference is used. Sorry for the confusion. I will request an ADC expert to look into this.

0 tlee over 7 years ago in reply to Hareesh Janakiraman

TI__Guru 62975 points

Hitoshi-san,

The VREFHI pin is not functional when the internal reference mode is used so it may be left floating or tied to a voltage. I would personally recommend connecting the pin to VDDA (or similar) so that the ADC can still be used in external reference mode for diagnostics or redundancy.

-Tommy

0 Hitoshi Sugawara over 7 years ago in reply to tlee

TI__Mastermind 21120 points

Hi Tommy,
Thank you for your recommendation.
Best regards,
Hitoshi

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TMS320F28069: VREFHI treatment when the internal reference is configured