TPS81256: Output Capacitor Value(Cext)

Sadanori Kato

Part Number: TPS81256

Hi,

The power-save mode output ripple voltage(ΔVout) is mentioned on page 5 of TPS81256 data sheet as below.
Could you please tell me the part number or the output capacitor value(Cext) which was connected to the output node in this case ?

Best regards,
Kato

over 6 years ago

0 Youhao Xi over 6 years ago

TI__Guru 68675 points

It should GRM188R61C475KAAJ by muRata as mentioned in the datasheet.

0 Sadanori Kato over 6 years ago in reply to Youhao Xi

Guru 36490 points

Hi Youhao-san,

Thank you for your reply.

I have an additional question.

What are the concerns if the effective capacitance value 1uF is used as the output capacitor ?
Is my understanding correct that the output ripple voltage is increased as the following equation ?

Best regards,
Kato

0 Youhao Xi over 6 years ago in reply to Sadanori Kato

TI__Guru 68675 points

Hi Kato-san,

Vout ripple is one concern. The other concern is loop stability. Recommended Cext = 2uF min to 30uF max per datasheet. I do strongly recommend the customer to follow the recommendations.

Thanks,

Youhao

0 Sadanori Kato over 6 years ago in reply to Youhao Xi

Guru 36490 points

Hi Youhao-san,

Thank you for your support.

I understood and will contact you if I get additional questions from our customer.

Best regards,
Kato

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TPS81256: Output Capacitor Value(Cext)