Hi,

I'm looking for a high speed zener diode. One that is capable of operating at hundreds of megahertz.

Are such devices available?
If so, which manufacturers and model ranges should i be looking at?


Thanks

 

Why? A reversed biased Zener diode is a high capacitative device and due to the doping needed for true Zener tunneling the breakdown is slow and noisy.

 

Because i want to build the application circuit found on the datasheet of this device http://ww1.microchip.com/downloads/en/DeviceDoc/md1820.pdf but with faster devices, so i can operate it at a higher frequency.

The zener and resistor shown in the MOSFET devices aren't in normal MOSFET devices. I imagine that the zeners are there for a good reason, most likely protection, and so i want include them.

Do you have a source for that nugget of knowledge nsaspook? How slow are we talking?

 

What zeners?
The only ones I see are inside the MOSFETs.

 

The input capacitance Ciss of the device (TC6320) ranges from 110 to 200pf at 1mhz. The depletion zone for a Zener must be very thin so there can be quantum mechanical tunneling across the barrier so it is heavily doped at high energy. This results in a high charge density and high junction capacitance across the zone that changes with the applied voltage. This junction capacitance and circuit impedance limits the breakdown speed of the Zener as it looks like a short with high speed signals.