TPS61021A: Information for adding snubber circuit.

Motoyasu Hattori

Genius 10955 points

Part Number: TPS61021A

Hi,

My customer wants to add a snubber circuit to the TPS61021A circuit. I have two questions as follows:

What is the parasitic capacitance of the SW pin when SW is OFF?
Although not mounted on the TPS61021A EVM, the schematic shows a 1 ohm resistor and a 1000pF capacitor. Can you tell me how you estimated these values?

Please advise us.

Thanks and best regards,
M.HATTORI

over 5 years ago

0 Brigitte over 5 years ago

TI__Guru 65200 points

Hello Motoyasu,

Please have a look to this short technical article:

Power Tips: Calculate an R-C snubber in seven steps

Ringing in switching power supplies can generate radiated and conducted noise, create circuit jitter and excessive dissipation, and easily overstress components. Ringing is a major concern in applications…

By John Betten over 9 years ago in Technical articles > Power management

The parasitic capacitance inside the IC is normally a lot smaller than the one on the board, so I would take the value from your board.

0 Helen chen over 5 years ago

TI__Mastermind 40080 points

Thanks Brigitte.

Hi HATTORI,

I'm very curious why you want to add RC snubber for such a low output voltage?

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TPS61021A: Information for adding snubber circuit.