Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

how to shutdown dual gate mosfet amp using logic signal ?

Status
Not open for further replies.

bobcat1

Advanced Member level 4
Joined
Jul 10, 2002
Messages
1,288
Helped
99
Reputation
198
Reaction score
34
Trophy points
1,328
Activity points
8,547
Need to shut down a small signal dual gate mosfet amp

the idea is to switch off the amp during transmit in a transciver ?


any idea



thanks

bobi
 

flatulent

Advanced Member level 5
Joined
Jul 19, 2002
Messages
4,629
Helped
489
Reputation
980
Reaction score
150
Trophy points
1,343
Location
Middle Earth
Activity points
46,689
two things

There are several ways. One is to turn the main Vdd voltage on and off. Another is to apply a gate bias that shuts off the drain current.

You should also consider disconnecting the input signal line to reduce the amount of transmitted signal power going to it which can either damage it immediately or do small damages that add up over time.

One standard way is to have a PIN diode in series with the line and one in shunt.

I know of one case where the input signal disconnecting was not complete and the amplifier would stop operating after about a hundred hours. A previous design with one series and two shunt (spaced a quarter wave apart) work well enough to not have any field failures.
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top