Hello all,

In a product, we are controlling the speed of a PMDC motor (12V, 80W, 
8.3A) by PWM (@ ~2 kHz).

In the setup, we use an IRF4905 MOSFET (International Rectifier, 
p-channel, -74A, 0.02ohm, -55V) and a freewheeling diode MBR3045 
(Vishay, Schottky, 30A). The MOSFET has its own internal diode as well. 
This setup works okay.

However, we would like to replace the MBR3045 with something like an 
MUR860 (ON Semi, Ultrafast, 8A average, 16A peak repetitive @ 20kHz) 
diode, since the MBR3045 seems to be an overkill.

What are the parameters that decide the selection of a freewheeling 
diode? If the motor is rated 8.3A @ 12V, should the FW diode be rated 
more than this?

Thanks,
Mohit Mahajan.
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