TPSM8D6C24: Snubber circuit

Kazuki Itoh

Part Number: TPSM8D6C24
Other Parts Discussed in Thread: TPS546D24A

Hi team,

Is the SW node snubber recommended for TPSM8D6C24 as well as TPS546D24A?
[SW-A/B]-[C1000pF]-[R1ohm]-[PGND]
The datasheet has some description about the snubber, but neither datasheet and EVM schematic has the snubber.
Does TPSM8D6C24 have internal snubber?
Do you recommended to leave pads for snubber?

Regards,

Itoh

over 3 years ago

0 Britton Jones over 3 years ago

TI__Genius 9286 points

Hi Itoh,

I saw that this question was duplicated in the following thread: TPSM8D6C24: Datasheet description - Power management forum - Power management - TI E2E support forums

I will respond to that thread and close this one.

Thank you,

Britton

0 Kazuki Itoh over 3 years ago in reply to Britton Jones

TI__Genius 11030 points

Hi Britton-san,

My apologies. As I have too many questions related to TPSM8D6C24, I unintentionally left the snubber part in the datasheet thread.

I removed the snubber question from the datasheet thread.

I believe it is better to seperate the snubber topic on the different thread for better visibility.

I'd appreciiate if you answer the snubber question in this thread.

Regards,

Itoh

0 Britton Jones over 3 years ago in reply to Kazuki Itoh

TI__Genius 9286 points

Hi Itoh-san,

No problem. I can address the issue here.

The datasheet's description of the snubber appears to be copied from the ICs datasheet. There is not an internal snubber in TPSM8D6C24.

Best regards,

Britton

0 Kazuki Itoh over 3 years ago in reply to Britton Jones

TI__Genius 11030 points

Hi Britton-san,

TPSM8D6C24 has SW_A and SW_B pins (pin #53 and #54).

They are not shown in the functional block diagram, but aren't they external switching node?

Regards,

Itoh

0 Britton Jones over 3 years ago in reply to Kazuki Itoh

TI__Genius 9286 points

Itoh-san,

Yes, that is correct. I will update my previous response accordingly.

In that case, if you want to take some precautions and have the flexibility to dampen the ringing and decrease the peak voltage during testing, please follow the datasheet recommendations of including provisions for a snubber network in the layout.

Best regards,

Britton

0 Kazuki Itoh over 3 years ago in reply to Britton Jones

TI__Genius 11030 points

Hi Britton-san,

Could you double check if TPSM8D6C24 really doesn't have the internal snubber components on the board?

I don't know what they are, but I can see some internal passives.

If it doesn't have internal snubber, why TPSM8D6C24EVM doesn't have provision for the snubber network in spite of the datasheet recommendation?

Regards,

Itoh

0 Britton Jones over 3 years ago in reply to Kazuki Itoh

TI__Genius 9286 points

Hi Itoh-san,

I will check on this internally. Will update you here.

Best regards,

Britton

0 Britton Jones over 3 years ago in reply to Britton Jones

TI__Genius 9286 points

Hi Itoh-san,

After double-checking the module schematics, I can confirm TPSM8D6C24 does not have an internal snubber.

For the question of why are provisions for a snubber not included on the EVM, I will check internally with the owner of the EVM who has insights on the design choices. They are out of office this week

Best regards,

Britton

0 Kazuki Itoh over 3 years ago in reply to Britton Jones

TI__Genius 11030 points

Hi Britton-san,

Thanks, I understand about the internal snubber.

I'm expecting your answer about the EVM.

Regards,

Itoh

0 Miranda Gu over 3 years ago in reply to Kazuki Itoh

TI__Genius 16632 points

Hi Itoh,

Britton will check then feedback to you. Appreciate your patiently waiting.

+1 Britton Jones over 3 years ago in reply to Kazuki Itoh

TI__Genius 9286 points

Hi Itoh-san,

The EVM is designed to meet TI's maximum rating for SW node voltage. In general, a snubber is not required however, some customers may want to provide one to achieve a more conservative SW node voltage rating.

Best regards,

Britton