TPS65986 burn out on on FW1.7.6

Gary Teng

Other Parts Discussed in Thread: TPS65982, HD3SS460

Dear sir,

My customer use TPS65986 in their dock product as Power source. They just upgrate their FW from FW1.5 (special version for PDO event timing) to FW1.76 and upgrate their board with 5V3A, 12V3A, 20V2A PD setting. They test 10 new boards. 3 failed on TPS65982 EVM communication (20V condition). 3 failed on Mac connection and 4 is good until 2 days test. Those failed IC has short (burned out) condition found on pads near PP5V and PP5V is short to GND. Is there any FW setting will cause IC burned out on PD communication? I attached my setting for 65986. Maybe you can review it and see anything wrong. Thanks for your kindly help.

Best regards,

Gary Teng

176test.zip

over 9 years ago

0 Jacob Ontiveros over 9 years ago

TI__Expert 6280 points

Hi Gary,

We have seen some corner cases when there is not capacitance on the PP_5V0 path. For USB I believe it is 120uF to 150uF bulk capacitance for 5V VBUS. Could you confirm?

We have an upcoming build that optimizes the PP_5V0 path for additional protection when there is not sufficient capacitance. If a firmware build is needed now, please send an email to usbpowerdelivery@list.ti.com and we can send a beta version.

Jacob

0 Gary Teng over 9 years ago in reply to Jacob Ontiveros

Genius 5840 points

Hi Jacob,

1. We see only 20uF cap on EVM or TI dock board design near TPS6598x side. Is 120uF cap is necessary on every tps6598x design for pp5V?

2. I get V2.4 FW tool already from your FAE Eric in Taiwan. Is that the same as you said above? We have test that FW and that can limit pluse on PP5V indeed. But we can't set the FW correctly for 2lane dp/ 2lane U3 application by using HD3SS460. Have you ever test that?

Thanks for your kindly help.

Gary

0 Jacob Ontiveros over 9 years ago in reply to Gary Teng

TI__Expert 6280 points

Hi Gary,

1. With the optimization on the PP_5V0 path it is no longer needed to prevent a reverse current spike. However, any design supplying VBUS must have 120uF according to the spec.

2. Yes, that should be the latest build. Yes we have tested this. Do you know if the multifunction bit is set for the DisplayPort alternate mode?

Jacob

0 Gary Teng over 9 years ago in reply to Jacob Ontiveros

Genius 5840 points

Hi Jacob,
I see the direct register seting page on tool for alt mode. I'll try that later. Thank you very much.

Gary

0 Gary Teng over 9 years ago in reply to Gary Teng

Genius 5840 points

Hi Jacob,
We set the multifunction bit on tool, but there's no data output until now. Can you mail me your project setting to gary.teng@arrowasia.com? Thank you very much.

Gary