LM61440-Q1: Bootstrap capacitor

xiaoming.tan

Part Number: LM61440-Q1

Hi team,

About the Bootstrap capacitor, in datasheet, it is recommended to choose a capacitor of 100nF, I want to know what is the range of values of a capacitor? If I choose 10nF or 1uF, what will be the impact?

over 1 year ago

0 Colin Chen over 1 year ago

TI__Genius 14041 points

Hi Xiaoming,

A small capacitance will cause Boot UVLO as datasheet described. A bigger capacitance will cause converter is hard to start up in prebias condition, because Cboot is charging too slowly to reach V_uvlo threadhold in start up with prebias.

B R

Colin

0 xiaoming.tan over 1 year ago in reply to Colin Chen

Prodigy 20 points

Hi Colin,

Thank you for your reply, is there an error limit for the capacitance here, such as ±10%, ±20%...

0 Colin Chen over 1 year ago in reply to xiaoming.tan

TI__Genius 14041 points

Hi Xiaoming,

±10%, ±20% is okay for Cboot error, thanks.

Colin

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LM61440-Q1: Bootstrap capacitor