DAC80508: SDO State with VDD Off

Shinichi Yokota

Part Number: DAC80508

Hello,

What's the state of DAC80508's SDO pin while the VDD (analog supply) is off but the VIO is on? It looks the SDO level is still High and disturbs SPI communication of the other SPI slave devices on a shared SPI bus.

In the system, the DAC80508's VDD is turned off when the system is put into a power-save mode. Hi-Z is expected at the SDO pin in this mode.

Best regards,
Shinichi Yokota

over 3 years ago

0 Paul_Frost over 3 years ago

TI__Guru 53943 points

Hi Yokota-san,

Webare confirming this behavior with out designers.

0 Illia Volkov over 3 years ago

TI__Intellectual 1755 points

Hi Yokota-san,

- EDITED to remove reference to multiple versions. There is only one version of the DAC80508 available. (Paul)

0 Shinichi Yokota over 3 years ago in reply to Illia Volkov

TI__Genius 9715 points

Illia,

What's the "revision" and how can I check it?

Best regards,
Shinichi Yokota

0 Illia Volkov over 3 years ago in reply to Shinichi Yokota

TI__Intellectual 1755 points

Please disregard that question. I am following up with the design team to help you with answering that question.

Thank you,

Illia Volkov

0 Shinichi Yokota over 3 years ago in reply to Illia Volkov

TI__Genius 9715 points

Illia,

A test confirmed that the SDO pin gets Hi-Z with /CS pin High when the VDD (analog supply) is turned off. Is it DAC80508's expected behavior by design? Or, is it just an accident?

Best regards,
Shinichi Yokota

0 Illia Volkov over 3 years ago in reply to Shinichi Yokota

TI__Intellectual 1755 points

Hello Yokota-san,

I just spoke to design team, and they confirmed that the while VDD is low and VIO and CS are high, the SDO pin will be in tristate/high impedance.

Did this help to answer your question?

Thank you,

Illia Volkov

0 Shinichi Yokota over 3 years ago in reply to Illia Volkov

TI__Genius 9715 points

Illia,

Illia Volkov said:
Did this help to answer your question?

Yes, thanks!

Best regards,
Shinichi Yokota

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DAC80508: SDO State with VDD Off