TPS650250: LDO unused pin

Hisao Uchikoshi

Genius 13510 points

Part Number: TPS650250

Hi Experts,

If customer does not use VLDO1, can be VLDO1 pin and FB_LDO1 pin left to open?

regards,

Uchikoshi

over 2 years ago

0 Brenda Diaz over 2 years ago

TI__Genius 15765 points

Hi Hisao,

Thanks for reaching out. The LDO1 and LDO2 on the TPS650250 share the same enable and supply signals. If a customer is using one of them and not the other, they will both be turned ON. The customer can follow what Michael Green had previously recommended on E2E "tps650250 unused LDO" (link below). Our recommendation would be to connect a small ceramic output cap on VLDO1 (for the not used LDO) and connect the corresponding FB_LDO1 pin directly to VLDO2 to use the external components of the LDO2.

Link to "tps650250 unused LDO": https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/339455/tps650250-unused-ldo

Thanks,

Brenda

0 Hisao Uchikoshi over 2 years ago in reply to Brenda Diaz

TI__Genius 13510 points

Hi Brenda,

Thank you for your reply.

Regarding FB_LDO1 pin, you recommend to connect directly to VLDO2 while Michael mentioned FB_LDO1 can be connected to VLDO1.

Brenda Diaz said:
nd connect the corresponding FB_LDO1 pin directly to VLDO2 to use the external components of the LDO2.

# Michael said"

"FB_LDOx can be directly connected to VLDOx - this way you save the external components for the feedback divider."

Which one is the better?

Regards,

Uchikoshi

+1 Brenda Diaz over 2 years ago in reply to Hisao Uchikoshi

TI__Genius 15765 points

Hi Hisao,

Since we are recommending a small output cap on the output voltage of the unused LDO and we don't know have information on the output voltage setting that customer will use for LDO2 (the one that is being used), then we recommend to connect FB_LDO1 to VLDO1 (FB pin of the unused LDO to its own regulator output).

Thanks,

Brenda

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TPS650250: LDO unused pin