Hi guys,
I thought of upgrading my buck converter's high side MOSFET. Previously, I was using IRF640NPbF (datasheet: http://www.irf.com/product-info/datasheets/data/irf640n.pdf).
Do anyone know if the following are the main criteria for searching a good mosfet (please let me know if I've missed some important considerations out):
If yes, what about the gate-charge? For a Gate-source voltage about 12V & Vds of ~100V, IRF640N has ~50nC but the Toshiba FET has ~150nC! (3X difference). Does this mean the Toshiba FET is not better than the IRF640? Or I can't made such comparison because the test Id is not the same, then what should we do?
Thanks.
I thought of upgrading my buck converter's high side MOSFET. Previously, I was using IRF640NPbF (datasheet: http://www.irf.com/product-info/datasheets/data/irf640n.pdf).
Do anyone know if the following are the main criteria for searching a good mosfet (please let me know if I've missed some important considerations out):
- Rds(on) - Commonly know for power dissipation since high Rds(on) represents higher voltage drop, hence more power loss
- Gate-charge - Lesser gate charge the better? Since the charge, hence time required for the MOSFET to turn on and off directly related to the gate charge?
If yes, what about the gate-charge? For a Gate-source voltage about 12V & Vds of ~100V, IRF640N has ~50nC but the Toshiba FET has ~150nC! (3X difference). Does this mean the Toshiba FET is not better than the IRF640? Or I can't made such comparison because the test Id is not the same, then what should we do?
Thanks.