BQ25883: BQ25883 Bootstrap capacitor

Zac Soden

Part Number: BQ25883

Hi, we are designing an application using the BQ25883 but I have a question about the 47nF bootstrap capacitor between pins SW and BTST. Since this is the only 47nF part on the PCB I want to know if it's acceptable to replace it with a 100nF capacitor instead?

Similarly, can I increase the 4.7uF REGN bypass capacitor to a 10uF ceramic without any ill effects?

over 2 years ago

0 Charles Harthan over 2 years ago

TI__Intellectual 1730 points

Hello Zac,

Increasing the REGN bypass capacitance is okay.

Increasing the BTST one should be, as well, but I am going to verify this on an EVM, and I will get back to you.

Regards,

Charles Harthan

0 Zac Soden over 2 years ago in reply to Charles Harthan

Prodigy 10 points

Hi Charles, thanks for confirming. Increasing the REGN capacitance will certainly help with simplifying the BOM. I appreciate you taking the step the verify the BTST capacitance and will await your confirmation.

+1 Charles Harthan over 2 years ago in reply to Zac Soden

TI__Intellectual 1730 points

Hello Zac,

From my tests, increasing the BTST capacitance affects the switching frequency of the device. The datasheet specs the BTST capacitor for .047uF, so this would be out of spec with the datasheet, so we cannot vouch for the performance. You can refer to page 69 of the datasheet to see how changing the switching frequency can affect the device.

Regards,

Charles Harthan

0 Zac Soden over 2 years ago in reply to Charles Harthan

Prodigy 10 points

Thanks again for checking, Charles. Given this information we will stick with the recommendation of 47nF.

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BQ25883: BQ25883 Bootstrap capacitor