[sdiy] [OT] High voltage signal switches / VCAs

[ASSI]

On Sonntag 06 Juli 2008, Antti Huovilainen wrote:
> I have potential tube project that would need digital / voltage
> controlled attenuators (VCAs or CMOS switches would do). The
> catch is that the attenuators need to stand up to +- 100V
> signal voltages. Is there a simpler way of making some than a
> bunch of relays or vactrols?

If you can switch resitors towards ground, then an antiserial 
configuration of small signal high voltage nMOS would do the 
trick (e.g. Infineon BSP372 or BSP297).  Drive the gate with 5V 
or more and the on-resistance is essentially flat with drain 
current.


Achim.
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