LMR23625: Schematic review request

NIBIN S

Intellectual 550 points

Part Number: LMR23625
Other Parts Discussed in Thread: TPS54302

Dear Team,

We are using 12V to 5V regulator (LMR23625CDDAR) in our design, the Schematics file is attached.

We are also providing an optional regulator (TPS54302DDCR) for checking better performance.

We request you to review and let us know the feedbacks.

Please let us know your feedbacks ASAP.

Thanks & Regards
NIBIN DAS S

over 7 years ago

0 NIBIN S over 7 years ago

Intellectual 550 points

Please find the schematics attached

0 Arief Hernadi over 7 years ago in reply to NIBIN S

TI__Mastermind 23845 points

Hi,

By itself the LMR23625 should be ok. But the TPS54302 FB reference voltage is different than the LMR23625 FB voltage therefore i dont think the TPS part will regulate at 5V

Thanks
-Arief

0 NIBIN S over 7 years ago in reply to Arief Hernadi

Intellectual 550 points

Hello Arief,

Thank you for quick reply.

When we use TPS54302, the FB resistor divider values we will be changed to C224=75pF, R270=100K and R269=13.3K.
Please let me know your feedback.

Regards,
Nibin

0 NIBIN S over 7 years ago in reply to NIBIN S

Intellectual 550 points

Hello,

Please find the layout file image for TOP and BOTTOM side attached.

Please review and let me know your feedbacks.

TOP:

BOTTOM:

Regards,
Nibin

0 Arief Hernadi over 7 years ago in reply to NIBIN S

TI__Mastermind 23845 points

Hi,

Are you using both supply to share the current or are you going to use the supply one at a time?

Thanks
-Arief

0 NIBIN S over 7 years ago in reply to Arief Hernadi

Intellectual 550 points

Hello Arief,

We will be mounting one regulator only at a time.

So there is no sharing of current.

Please let me know your feedback on the placement file shared earlier.

Regards,

Nibin

0 YangZhang over 7 years ago in reply to NIBIN S

TI__Genius 11085 points

I will comment on the layout of the LMR23625.

Input capacitors, especially C221, should be right next to VIN and PGND pins of the IC, for the best high frequency bypass result. C220/C219 should be right outside of C221. Now, C221 seems to have a thin trace to a via to ground plane. It should have direct connection to PGND pin.

FB is a sensitive node, the copper trace to FB pin should be as short as possible. It seems there's a copper pour on the FB pin, please remove the pour and use thin traces on FB.

The exposed DAP is mainly for heat sinking. Please extend the copper underneath the IC out as much as possible to spread the heat out.

Traces on VCC and BOOT pins should be wider. Wider traces reduce parasitic inductance, which is not desired to see on these two pins.

Best regards,

Yang

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LMR23625: Schematic review request