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pls help me with this circuit

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Junior Member level 3
Sep 11, 2005
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hi everybody,

i'm designing a 2 meter band PA using this circuit. pls suggest to me what software to use to simulate this circuit on the pc to get results. i also need to know what type of wire i need to use for the power supply input that 28v. should the wire be very thick. i'll also like to know what is the function of a vhf choke in this circuit.

If you can get the device model,including active and passive,you can use ADS or MWO to do the simulation.It seems the input current is not very high in this case(around 200mA),i think you donot need to use too thick cable to handle that.The additional VHF choke is to realize low pass function better than just one inductor,similar as you use several capacitors connected in parallel to short the RF signals.

Would be hard to find a Spice model for this high power transistor to put into a simulator, but probably not impossible.

Usually the manufacturer post in the datasheet only the Series Equivalent Input–Output Impedance at maximum output power, to help finding the matching components.

Collector efficiency is 60% @ 28V, that means the maximum Ic could be up to 6.5A at 100W RF output power (160W DC input power).
So, definitely you need a wire sufficiently thick to don’t have voltage drop for the length.

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