TDP158: VDD power up timing faster than VCC

Statham Su

Part Number: TDP158

Hello Sir:

We got one damage PCBA and measured power up sequence that we found VDD power up timing faster than VCC.

After we reworked and fine tuned it that power up sequence became normal, but that failure PCBA's TDP158 cannot work again.

Does failure power up sequence will make TDP158 damage?

If not, would you please provide some troubleshooting ways for us?

Looking forward your feedback.

Thanks a lot.

over 1 year ago

0 David (ASIC) Liu over 1 year ago

TI__Guru**** 177241 points

Hi,

Please see the power up timing for TDP158 as shown below. Keeping OE low until VDD and VCC becomes stable avoids any timing requirements as shown in Figure 8-3.

Thanks

David

0 Vishesh Pithadiya over 1 year ago in reply to David (ASIC) Liu

TI__Mastermind 39315 points

Additionally please validate that the ramp up and delay times are within spec as well.

0 Vishesh Pithadiya over 1 year ago in reply to Vishesh Pithadiya

TI__Mastermind 39315 points

Typically you want VCC stable before VDD, but this should not break the device, as the required delay between the two is 0ms. Have you tried a different TDP158 chip on the reworked board?

0 Vishesh Pithadiya over 1 year ago in reply to Vishesh Pithadiya

TI__Mastermind 39315 points

Hey Statham,

I'm closing this thread due to inactivity.

0 Statham Su over 1 year ago in reply to Vishesh Pithadiya

Genius 4990 points

Hi Vishesh:

Sorry, we are checking it and fine tune it.

Please refer below waveform which is our power up sequence.

Would you please help to check does it work for TDP158?

TDP158.pptx

The other, according preview failed symptom we also updated CPR.

Please refer our attached file which, which shows schematic, and resistance table of each pins.

Failure analysis request form_2.0_TDP158_20231212.xlsx

We found which VDD and VCC pins got some damage, would you please also recommend us how to avoid this damage?

Looking forward your feedback.

Thanks a lot.

0 Vishesh Pithadiya over 1 year ago in reply to Statham Su

TI__Mastermind 39315 points

Hey Statham,

This may take some time to fully address and narrow down the issue/ find a solution or workaround. Ill look into this and have an update in a few business days.

0 Vishesh Pithadiya over 1 year ago in reply to Vishesh Pithadiya

TI__Mastermind 39315 points

Like seen in the screenshots from the datasheet above, the timing should be ok now as long as VCC is asserted before VDD.

When is OE asserted with respect to the VCC and VDD becoming stable? OE must be asserted at least 100us after VDD is stable.

Regarding the damage done to the pins. I'm not sure how to avoid damage, as I'm not sure what caused the pins to short out. I recommend making sure all timing of signal are accordioning to the datasheet, as not following spec can lead to unforeseen outcomes.

0 Statham Su over 1 year ago in reply to Vishesh Pithadiya

Genius 4990 points

Hi Vishesh:

Sorry it's taking a long time to collect all failure samples and symptom.

This case is a little bit complicated, I need to share customer schematics for you.

We had 5pcs failed TDP158 returned from customer side, which from 3 different mother board.

Even which from 3 different mother board, but failed used case is the same condition, it's failed when working stage, it's not in hot plug or not in suspend resume.

Can we discuss this issue by E-mail?

my e-mail address is "statham.su@arrow.com".

Looking forward your feedback.

Thanks a lot.

0 Statham Su over 1 year ago in reply to Statham Su

Genius 4990 points

Hi Vishesh:

Would you please contact with us?

We have layout and schematic which needs to share with you.

Looking forward your feedback.

Thanks a lot.

0 Vishesh Pithadiya over 1 year ago in reply to Statham Su

TI__Mastermind 39315 points

Hey Statham,

I'm not allowed to move E2E threads to email. I will send a friend request to you on E2E and we can continue on the private channel.

Logging for private message: https://e2e.ti.com/support/interface-group/interface---internal/f/interface---internal-forum/1317446/tdp158-e2e-cont-on-private-message-here

Interface

Interface forum

TDP158: VDD power up timing faster than VCC