Amplifier design using PD85004 LDMOS

[adnan012]

Hi,
I am trying to design a broad band amplifier ( 300MHz-500MHz) using PD85004.
The required output power is less than 1 watt.
PD85004 ADS model is available.

How can i start the design using ADS? What are the appropriate steps? I want to follow the following Phillips Application Notes in designing the amplifier and matching networks.

"A wideband power amplifier (25 − 110 MHz) with the MOS transistor BLF245" and
"RF transmitting transistor and power amplifier fundamentals"

 

[kspalla]

you may start with the demo board from the link given below

www.st.com/stonline/products/literature/ds/16743/db-85004-340.pdf

 

[adnan012]

I have already simulated the demo board.
The problem i am facing is that in Philips application note "A wideband power amplifier (25 − 110 MHz) with the MOS transistor BLF245" the mos output is represented by the output capacitance with a resistor in parallel. They calculated the resistor value by using Rl=(v^2)/2*Pout. For my design it becomes
Rl= (13.6)^2/2*1=92.48 ohm . Next the output filter is designed by by using the rc combination. My question is that, how can i simulate it in ADS. How load resistance Rl is realized in ADS?

 

[kspalla]

You need to use ADS model as the impedance at your band are not available to you.