LP2998: How to determine Cout value

Takashi Onawa

Part Number: LP2998

Hi Team,

My customer want to design new board with LP2998 but they didn't understand well how to determine Cout value from the datasheet description.

Could you tell me how the amount of Cout should be determined easily?

Regards,

Takashi Onawa

over 3 years ago

0 Weidong Zhu over 3 years ago

TI__Expert 5965 points

Hi Onawa-san,

The output capacitance is determined by the transient requirement of VTT rail. As a rule of thumb total capacitance between 100uF to 200uF should satisfy most of typical applications.

Regards,

Weidong

0 Takashi Onawa over 3 years ago in reply to Weidong Zhu

TI__Genius 13200 points

Hi Zhu-san,

Thank you for your prompt response on this.

One quick question.

My customer plan to use ceramic cap for the output though, you mean they need to put 100 to 200uF as effective value, right?

Also, do you think they should have some spare land pad other than the value above?

Regards,

Takashi Onawa

0 Weidong Zhu over 3 years ago in reply to Takashi Onawa

TI__Expert 5965 points

Hi Onawa-san,

Yes, you are right, the recommended value is the effective capacitance if it's ceramic capacitors. It's always a good idea to reserve some spare land pad if space is not an issue.

Regards,

Weidong

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LP2998: How to determine Cout value