MP28167-A Bootstrap Capacitors Rating

Hello, we are considering MP28167-A in a test device and the converter needs two 0.1μF bootstrap capacitors. Due to PCB size limitations we want to use capacitors with a smaller footprint.

I didn’t find a recommended voltage rating for the capacitors. The absolute maximum rating states VBSTx - VSWx < 4V. Can I take that information and use 6.3V rated MLCC capacitors, or do I need extra considerations? This voltage rating seems rather low.

I would also like to ask whether the rating is the same for MP28167, MP8859, MP8860/2, as these SKUs seem to be derived from the same die.

Please advise and thank you.

Hi Joshua,

The voltage rating of a capacitor may depend on how much voltage you expect across it. Typically, I believe it is good to leave margin because the effective capacitance after the voltage bias may drop if the voltage rating is close to the bias voltage.

In general, you can check the characteristics of the capacitor across voltage, temperature, etc. to ensure if that can work.

You can refer to the evaluation board as well.
EVL28167-A-Q-00A | 22V, 3A, Synchronous Buck-Boost Converter with I2C Interface for Power Delivery Evaluation Board | MPS (monolithicpower.com)

Best Regards,
Yu

Thank you, I see the EVB uses 50V 0402 capacitors. 6.3V is not a lot of margin and I will double check available capacitors for a safer rating.