Clint Mclean
New Member
Does anyone know how I can get the best out of this JFET for an RF amplifier between 200 MHz and 1GHz:
https://www.mantech.co.za/Datasheets/Products/J30X.pdf
The manufacturer says that it has excellent high frequency power gain (Gps) of 11 dB at 400 MHz.
They mention that's with:
VDS = 15 V
ID = 5 mA
in a common source configuration.
So that should produce a Voltage or Current Gain (Vout/Vin) > 3?
I'm not sure of how to bias it to achieve that. If someone could show that it's possible with LTSpice I'd really appreciate it.
Here's the LTSpice specification for the J304 from https://ltwiki.org/?title=Standard.jft
.MODEL J304 NJF(Beta=729u Betatce=-500m Rd=1 Rs=1 Lambda=10m Vto=-3.52 Vtotc=-2.5m Is=33.57f Isr=322.4f N=1 Nr=2 Xti=3 Alpha=311.7 Vk=243.6 Cgd=2.17p M=362.2m Pb=1 Fc=500m Cgs=2.205p Kf=5.58e-003f Af=1)
Alternatively does anyone know of a better way of building an amplifier for the 200 MHz to 1 GHz range. Quality of the signal is not required, I just want to detect that it's there. I'm going to amplify it and then convert it to a DC voltage using the circuit in the attached image.
Thanks
https://www.mantech.co.za/Datasheets/Products/J30X.pdf
The manufacturer says that it has excellent high frequency power gain (Gps) of 11 dB at 400 MHz.
They mention that's with:
VDS = 15 V
ID = 5 mA
in a common source configuration.
So that should produce a Voltage or Current Gain (Vout/Vin) > 3?
I'm not sure of how to bias it to achieve that. If someone could show that it's possible with LTSpice I'd really appreciate it.
Here's the LTSpice specification for the J304 from https://ltwiki.org/?title=Standard.jft
.MODEL J304 NJF(Beta=729u Betatce=-500m Rd=1 Rs=1 Lambda=10m Vto=-3.52 Vtotc=-2.5m Is=33.57f Isr=322.4f N=1 Nr=2 Xti=3 Alpha=311.7 Vk=243.6 Cgd=2.17p M=362.2m Pb=1 Fc=500m Cgs=2.205p Kf=5.58e-003f Af=1)
Alternatively does anyone know of a better way of building an amplifier for the 200 MHz to 1 GHz range. Quality of the signal is not required, I just want to detect that it's there. I'm going to amplify it and then convert it to a DC voltage using the circuit in the attached image.
Thanks