Maker Pro
Maker Pro

Clean 20Mhz square wave at 45 volts ... possible???

royalmp2001

May 20, 2014
11
Joined
May 20, 2014
Messages
11
Hi everyone,
Been trying to see if anything like this is possible.
I have got a IRF610 mosfet to switch at 1Mhz at 33 volts but the waveform is not clean and looks more like a distorted triangle wave. Going up to 2Mhz the voltage swing drops completely.
I know I could use a faster Mosfet...
I am driving the gate from a 9v function generator via a 100 ohm resistor. The mosfet load is a 750 ohm resistor connected from +33volts to drain and I have a 50Mhz oscilloscope connected across the load. I also have a 15k resistor connected from gate to source.
Thoughts, anyone.?
Different resistor values or additional components?
Thanks
 

Bluejets

Oct 5, 2014
6,087
Joined
Oct 5, 2014
Messages
6,087
Gate capacitance is probably causing grief.
Maybe use a mosfet driver?
 

Alec_t

Jul 7, 2015
3,287
Joined
Jul 7, 2015
Messages
3,287
Many function generators are intended for driving low current loads only. As Bluejets says, a dedicated FET driver may help, since it is designed to handle high current needed to charge/discharge the gate capacitance quickly.
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
I do not think this is possible. You need several harmonics to get anything near a square wave so will need to amplify at least 100MHz.
 
Top