PIN diode for RF switching

This guy gives a great tutorial on PIN diode switches and mentions that the one he is showing was used in a 50W transceiver.

Maybe helpful.

I've used MACOM pins, but only tiny ones, basically signal level. I used them for switching attenuators in and out in a pulse application, which didn't work well. Pulses got distorted more than I expected.

If you don't need switching speed, you might consider a relay. I like the tiny, cheap Fujitsu telecom parts, which are sure easy to drive compared to a PIN.

Am 02.04.23 um 19:16 schrieb John Larkin:

PINs do not work well when there a frequencies below 2 MHz involved. Some go a little bit deeper, but not much. And carrier lifetime is unknown to Spice, so the simulations are not realistic.

Gerhard

Ummm... he says 150 to 450 MHz. That's a bit higher than 2MHz.

Problem is I need the speed. Just thinking I forgot about the 100 watt amp I have so needs to handle 100 watts at 450 MHz.

Project is using an amplifier to get more power for a DMR radio at 450 MHz.

There is not much difference in driving the PIN or relay as this is going to be RRF switched and not hard wired.

You might succeed in using an old (slow) power rectifier diode, which has PIN structure.

You need to provide enough forward current to conduct without (much) waveform distortion, and more than the peak RF voltage to turn it off, but that's all PIN diodes.

The only real question is whether the off capacitance (reverse biased) provides enough attenuation, but if not, use more stages.

Clifford Heath.

No. JL wrote about a pulse application with unknown (to us) switching times.

Gerhard

It was a shaped pulse, max 25 ns wide, that modulates a rather large laser. The PIN lifetime is specified at 200 ns, but maybe that means really, really depleted. At any rate, the PIN wrecked the waveform.

This was a home-made single-step attenuator, and the PIN was an on/off switch to ground; I expected that to work. I changed it to a SAV541 phemt, which worked fine.

I haven't looked for awhile, but check Macom. They bought Metelics too, so they have a lot of stuff.

Skyworks had some stuff too, but less of a selection.

I was looking into stuff at that power, but higher frequency. Chip'n'wire microcircuit stuff. But these companies have the diodes.