DAC9881: output voltage is not correct sometimes after power-on

Jerry Chen

Part Number: DAC9881

Hi team,

My customer found sometimes output voltage is not correct after power-on. I have checked the power up sequence and RSTSEL &USB/BTC setting. No suspect was found. I would like to know if anything else I could take a look at.

I saw when the issue happened, SDI (CH2 in below figure, CH1 is SCLK) is high in IDEL status, but it is low when no issue happened.

Thanks.

over 3 years ago

0 Paul_Frost over 3 years ago

TI__Guru 53563 points

Hi Jerry,

Can you confirm the power on sequence of the device? Specifically if IOVDD is applied before AVDD.

Thanks,

Paul

0 Jerry Chen over 3 years ago in reply to Paul_Frost

TI__Expert 5110 points

Thank you, Paul.

Yes, I saw IOVDD is 200us before AVDD. Do we have recommended delay time between AVDD and IOVDD?

0 Paul_Frost over 3 years ago in reply to Jerry Chen

TI__Guru 53563 points

Hi Jerry,

I do not have a time limit, but I would recommend the it be fully settled before the AVDD input rises. Does toggling the /RST pin allow the system to recover?

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DAC9881: output voltage is not correct sometimes after power-on