Solutions for Switching FETs

[infinite_gbps]

Hi,

From what I understand one needs to block AC signals when using DC to switch FETs. Again, from what I understand some inductors are using in series with the driver circuit for a FET switch.

Doesn't this slow your switching speed down? If it does what are some creative solutions to avoiding or battling this effect? Minimizing it should be a better way of asking.

Thanks.

 

[randell_xtian]

hi!

first, what would be the time of respond do you need (trr)? second the minimum and maximum frequency do you what to switch on and off the fet? it can be calculated by f= 2piXL.

 

[infinite_gbps]

Hi, thanks for the reply. I want to switch at 5 ns but can currently live with 20 ns (switch speed). The frequency of interest is min = 200 MHz and 400 MHz.

The FET switch requires 0 & -5V for switching. The driver circuit is simple just need to know how to get around the inductance slowing my switch control signal.

Anyone seen any creative solutions? Thanks.

 

[randell_xtian]

hi,

try to place a fast switching diode (1SS133) to the inductor (parallel connection). the connection should be reverse to the supply voltage.

 

[jayce3390]

How do you proceed to generate a 400 MHz pulse signal to switch a FET?

From what I know, pulse generators are not able to run so fast.