Simple Diode Question......

Hey all,

What type of diode is generally recommended for a circuit operating at radio frequency between 10 and 20 MHz? I am trying to provide good half-wave rectification.

I've used a 1N4148 type diode but the rectification becomes very noisey at frequencies over a few hundred KHz.

Would a small signal Germanium diode do the trick?


Cheers

Cat

1n4148 is a silicon junction diode. You can tell because its Vf at say 10 mA is around 0.7 volts. Junction diodes are SLOW to respond to RF signals, and typically have too much junction capacitance to be useful.

Try a Schottky diode, with a Vf in the zero to 0.4 volt region, and a capacitance of less than say 5 pF. HSMS-2822, HSMS-2852,HSMS-2804, etc.

thanks for the advice, are they all surface mount devices?

They are surface mounted. Data sheets with SPICE parameters, etc are here:

http://www.avagotech.com/

(search field in upper right corner)

if u want astable circuit u can email me at ilotfy@gmail.com