DRV8242-Q1: How to calculate VM input capacitance of DRV8242?

Zoe Yang

Part Number: DRV8242-Q1

Hi team,

Do we have any reference equation that could calculate the capacitance on the VM input power? Customer 12Vin power and peak current 3.8A.

over 1 year ago

0 Jacob Thompson over 1 year ago

TI__Mastermind 23431 points

Hey Zoe,

Do you mean what the bulk capacitance should be for the system? For a 12V/3.8A system with this driver a good start would be 100 uF. You might be able to get away with less (47 uF, I wouldn't try much lower), but I recommend testing it with an EVM first - https://www.ti.com/tool/DRV8242S-Q1EVM Here is an app report about Input and Output Capacitor Selection that can be used to help you calculate the bulk capacitance for your system.

Also see 5 Bulk and Bypass Capacitor Placement in Best Practices for Board Layout of Motor Drivers

The input capacitance for the VM pin is typically a few pF ( assume 10pF max ).

Best,

Jacob

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DRV8242-Q1: How to calculate VM input capacitance of DRV8242?