I need to drive 2 logic level MOSFETs from digital outputs of a microcontroller (3.3V). These will be used to drive a low-power push-pull converter at 500 kHz. I have identified these "double" MOSFETs:
- ROHM US6K4: https://fscdn.rohm.com/en/products/databook/datasheet/discrete/transistor/mosfet/us6k4.pdf
- Vishay SQ1912EH: https://www.vishay.com/docs/67394/sq1912eh.pdf
- Infineon BSD235N: https://www.infineon.com/dgdl/BSD235N_Rev2%205.pdf?fileId=db3a30431add1d95011afc70075c04e0
I have a doubt about the gate resistor.
- In ROHM and Infineon datasheets, many characteristics are given for a certain Rgs (usually in the range of 10 Ω) and I guess that is a reasonable value to be used for the gate resistor in my final design, in order to avoid ringing and to keep good switching performances.
- Vishay datasheet indicates an explicit value of Rg (test condition: 1MHz ????), and it sounds like a resistor embedded into the component. I'm quite confused with this specification.
Is there anyone who has experience with this kind of logic level MOSFETs and can tell me if an external gate resistor is actually needed and if Rg ≈ 10 Ω is a reasonable value?