TPA3129D2: Startup problem with TPA3129

Gavin Melville

Part Number: TPA3129D2

We are using a TPA3129D2 and it appears occasionally to start with the wrong gain. When during the power up sequence is the gain voltage sampled ?.

From Data Sheet SLOS941C, May 2016, updated Jan 2018 "The gain setting is latched during power-up and cannot be changed while device is powered."

We are finding the gain "voltage" very noisy, and knowing when it is being sampled would help.

Scope piccy of the PVCC rail (yellow) and the gain pin (blue)

over 1 year ago

0 Yanming Gong over 1 year ago

TI__Mastermind 19360 points

Hi,

Could you share customer schematic and PCB layout to me?

The Gain setting will be latched with power-up when SDZ pin is high. The end of the start-up cycle is when SDZ is high.

So could you monitor SDZ and Gain pin waveform together?

And if Gain pin is not stable, you can pull low SDZ pin to delay some time, then pull high SDZ pin when Gain pin is stable.

0 Gavin Melville over 1 year ago in reply to Yanming Gong

Prodigy 10 points

Hi Yanming,

There are IP issues, so no public schematics. Likely the problem is SD coming up with PVCC/AVCC. It would have been great if this was in the data sheet. I'll get our FAE to reach out to you by email.

0 Yanming Gong over 1 year ago in reply to Gavin Melville

TI__Mastermind 19360 points

Hi Gavin

I will follow email. Now I will close the E2E.

Thanks!

Regards,

Derek

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TPA3129D2: Startup problem with TPA3129