DAC8718: DAC8718 power supply problem

user5162383

Part Number: DAC8718

HI, I'm testing DAC8718.

I got a problem that DAC8718 outputs error after power-on, the error output is zero and the right ourput is -15V. then It always outputs +15V when I try to control it.

The wrong phenomenon is very accidental.

I read the paragraph on Power-on Reset Sequencing on page 44. So I test the power sequence.

CH1 is 5V for DVDD, CH2 is 3.3V for IOVDD, CH3 is +15V for AVDD, CH4 is -15V for AVSS

My schematic as follows:

what should I initialize for DAC8718?

Thanks for reading.

over 5 years ago

0 Uttam Sahu over 5 years ago

TI__Genius 14220 points

Hello,

Welcome to E2E and thank you for your query. I am looking into your issue. I will get back by tomorrow.

Regards,
Uttam Sahu
Applications Engineer, Precision DACs

0 Uttam Sahu over 5 years ago in reply to Uttam Sahu

TI__Genius 14220 points

Hello,

As the problem is occuring less often, I suspect the OFFSET register might not be getting initialized at power-on due to some reason. Is it possible to measure the OFFSET pins so that we can know whether they are getting loaded properly or not?

Another point, I am not seeing any de-caps in the schematics. I hope you have mounted them.

Regards,
Uttam

0 user5162383 over 5 years ago in reply to Uttam Sahu

Prodigy 50 points

Hello,
Thank you for your reply. I'm sorry I've got a little late reply. I think I have got the cause of the problem. Perhaps because of the unusual sag in the 15V and 5V power up process. I adjust the peripheral circuit of the power module. The problem is missing.
de-caps are in the another schematics. Thank for your reminding。
Regards,
Chris Lee

0 Uttam Sahu over 5 years ago in reply to user5162383

TI__Genius 14220 points

Hi Chris,

Glad to know that your issue got resolved. Please reach out to us whenever you need support in future.

Regards,
Uttam

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DAC8718: DAC8718 power supply problem