MOSFET Rds(on) Calculator

Calculate on-state resistance at operating temperature and gate voltage conditions.

Input Parameters

Rds(on) at 25C

mOhm

Junction Temperature

Gate Voltage (Vgs)

Reference Vgs (datasheet)

Temperature Coefficient

%/C

Rds(on) at Operating Conditions

68.8 mOhm

Temp Factor

1.38x

Vgs Factor

1.00x

Max Current (1W)

3.81 A

Rds at Tj only

68.8 mOhm

Rds(on) vs Temperature

50C: 56.3 mOhm75C: 62.5 mOhm100C: 68.8 mOhm125C: 75.0 mOhm

Rds(on) Theory

Rds(on) increases significantly with temperature due to reduced carrier mobility. The positive temperature coefficient helps with current sharing in parallel MOSFETs but must be accounted for in thermal design.

Rds(Tj) = Rds(25C) x (1 + alpha x (Tj - 25))