IN3LBQ on the Hühnerspiel (Amthorspitze) - photo by IN3OTD

Mitsubishi RD100HHF1 LDMOS model

Under construction...

The Mitsubishi RD100HHF1 is a high-power LDMOS used in the final stage of commercial HF radios and in some homebrew amplifier projects.

Model for Vdd=12.5 V and Idd= 800 mA

Typical S-parameters for this device can be found on the Mitsubishi web site, for a supply voltage of 12.5 V and a drain current of 800 mA.

Using the extraction method previously described, considering only the S-parameters from 50 MHz to 500 MHz, the following small-signal model parameters are determined:

Rg = 0.576 ohm
Rd = 0.406 ohm
Rs = 0.021 ohm
Lg = 0.504 nH
Ld = 0.691 nH
Ls = 0.041 nH
Cgs = 248 pF
Cds = 173 pF
Cgd = 13.9 pF
gm = 2.36 S
gds = 3.53 mS
So the equivalent small-signal circuit for this LDMOS at 800 mA drain current is the following: RD100HHF1 small-signal model - 800mA Smith chart with measured vs. model S-parameters: measured vs. modeled RD100HHF1 S-parameters - 800 mA S-parameters fitting details - fitted region is in white background: RD100HHF1 S11 800mA S12 fit seems poor, but this is mainly due to its low value and noisy measured data: RD100HHF1 S12 800mA RD100HHF1 S21 800mA RD100HHF1 S22 800mA