PMOS NPN configuration to drive CGHV1A250F

Thread Starter

yef smith

Joined Aug 2, 2020
838
Hello ,The main goal is to Bias the CGHV1A250F transistor which is represented as 3 Ohm load resistor.shown below using PMOS shown below datasheet and spice model.LTspice file is attached with the imported spice model of the PMOS.
I know the conditions for opening PMOS and NPN shown below.
Suppose my pulse is in ON state.

Given the diagram below,what is the strategy for formulating the current that will be flowing threw as a function of NPN and PMOS expressions?
So i'll know what is the role of each element an how it influences the current going into the load resistor.
Thanks.




https://pdf1.alldatasheet.com/datasheet-pdf/download/1673867/WOLFSPEED/CGHV1A250F.html

PMOS:
https://eu.mouser.com/ProductDetail/Nexperia/BC848B215?qs=me8TqzrmIYWVIx0akKpYzQ==&utm_id=6470900564&gad_source=1&gclid=CjwKCAjw3NyxBhBmEiwAyofDYdMdsOjuIRXNOO_IIm4SrIL6_HIKGgpEd1vVxYqDajgA0278Mks_wBoCL90QAvD_BwE&_gl=1*13gajfk*_ga*NDE2MTI4MDYzLjE3MTQ5MTU3NTM.*_ga_15W4STQT4T*MTcxNDkxNTc1My4xLjAuMTcxNDkxNTc1NS41OC4wLjA.

PMOS spice model:
https://www.vishay.com/doc?76129
1714916636634.png
1714916482802.png1714921743325.png
 

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Thread Starter

yef smith

Joined Aug 2, 2020
838
Hello, Yes you arec orrect, i missed a resistorR 3 as shown below.
If we start from the NPN, what is the mathematicl epression for suchcase?
Thanks.

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crutschow

Joined Mar 14, 2008
34,844
Exactly what bias values to you want for the transistor?
I would expect you need a voltage source, not a current-source as you circuit provides.
 

Thread Starter

yef smith

Joined Aug 2, 2020
838
I want my CGHV1A250F transistor to be in normal operation mode, from data sheet i know that drain needs o be 28V.
However they only say the quecent current. When a small signal(RF) will enter) the current will get higher threw the drain because gm transimpedance will start working.What current shuld i use that will pass threw my load CGHV1A250F?(represented as a resistor in the circuit)
Thanks.
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Thread Starter

yef smith

Joined Aug 2, 2020
838
Hello crutschow, What kind of configuration do you reccomend for biasing the load CGHV1A250F transistor ?
 
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