Switching at MHz frequency with a heavy load

[yoyolk]

Hi,

I am kind of looking for or design a switch/relay that can be driven at AC condition with the frequency around 1MHz or a few hundred kHz and the drive voltage is better less than 15V. I have found a relay that can switch at ns. However, since the switch has an internal capacitance around pF, and my load device probably has resistance around 100M ohm. It turns out when I connected my device to that switch, it can only be driven at a few Hz. Can anyone help me?

 

[srizbf]

if the relay you are talking about is a mechanical relay ,
no way of switching atkhz , leave alone Mhz.

very few hz .
relays mechtypes, are not meant for that.

your reference to finding a relay that switch at ns , is only switching time (settling).
not the repetitve time.


srizbf
18thmay2010

 

[biff44]

If you want to get useful advice, you will have to give us detailed information about what this mysterious "device" is. The parasitic capacitances, coupled with the "100 M ohm" resistance, will not allow 1 MHz operation.

 

[yoyolk]

If you want to get useful advice, you will have to give us detailed information about what this mysterious "device" is. The parasitic capacitances, coupled with the "100 M ohm" resistance, will not allow 1 MHz operation.

The device I meant here is the Source/Drain terminal of a MOSFET. When the switch is closed, the MOSFET will be turned on and therefore the resistance of the Source/Drain terminal is around tens Ohm. When the switch is open the MOSFET will be turned off and the resistance of the Source/Drain terminal is expected to be around 100M Ohm or even higher. Please let me know if there is anything that is not clear.