DAC5682Z: DVDD AVDD start-up sequence

Miranda Gu

Genius 14757 points

Part Number: DAC5682Z

Hi team,

According to DAC5682Z datasheet, the power of DVDD should be earlier than AVDD.

However, the AVDD on my customer's board is earlier than DVDD. Currently, their test results are normal.

The following is the test waveform, AVDD is about 25ms earlier than DVDD.

If it is used for a long time, will it cause damage to DAC5682Z? Are there any potential risks? Should customer modify the start-up sequence?

over 3 years ago

0 Miranda Gu over 3 years ago

TI__Genius 14757 points

Hi team,

Could you pls check whether AVDD can be earlier than DVDD?.

Many thanks!

0 Ebenezer Dwobeng over 3 years ago in reply to Miranda Gu

TI__Genius 9695 points

Hi Miranda,

The problem seems to be the rise time. A potential solution will be to increase capacitance on AVDD rail to make the rise time higher than that of DVDD.

Other solution will be to tie the "power good" pin of DVDD power chip (if available) to the enable pin of AVDD power chip (if available)

I can only recommend the sequence as in datasheet.

Thanks,

Eben.

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DAC5682Z: DVDD AVDD start-up sequence