How to measure Rds(on) Power NMOs?

[chungming]

Hi ~~
I have a Power MOSFET, and want to measure it Rds(on).
but there are many method to measure it,
could any body can tell me a easy and precision method to measure it!
thanks ~!!

 

[dumbfrog]

Define your gate voltage first (Vgs will affect Rdson)
Force a current source (Drain side and Source is the ground) and measure the voltage and calculate V/I=R
OR fource a voltage source and measure the current and calculate V/I=R

 

[gte582w]

also make sure at worst case which corresponding
to minimum Vgs, you size your xtor large enough
to provide small enough dropout voltage.