bootstrap analog multiplexer

[gravpoet]

I need an analog multiplexer that can process ±40V DC voltage
inputs...any ideas ?

I've seen some info on bootstrapping of op amp supplies to get higher
output voltages...I'm wondering if this technique or something similar
can be applicable to to analog multiplexers ?

Thanks

 

[Joerg]

I need an analog multiplexer that can process ±40V DC voltage
inputs...any ideas ?

I've seen some info on bootstrapping of op amp supplies to get higher
output voltages...I'm wondering if this technique or something similar
can be applicable to to analog multiplexers ?

Nope, you just buy'em

Supertex makes HV muxes:
http://www.supertex.com/products/selector_guides/100

 

[gravpoet]

Alternatively; attenuate, multiply and amplify. Whatever floats your boat.

Thanks for your input.

The mux is at the (+) input of an op amp configured as a voltage
follower. My design requires 1GΩ of input impedance minimum which
would preclude resistor type attenuators. I am assuming that is what
you were referring to. I may have better luck looking for an accurate
"active" attenuator (?).

The Supertex devices in the previous post may be a good
solution...I'll have to review the specs.

 

[Winfield Hill]

Thanks for your input.

The mux is at the (+) input of an op amp configured as a voltage
follower. My design requires 1GΩ of input impedance minimum which
would preclude resistor type attenuators. I am assuming that is
what you were referring to. I may have better luck looking for
an accurate "active" attenuator (?).

The Supertex devices in the previous post may be a good
solution...I'll have to review the specs.

There's also the possibility of using optically-switched
MOSFET switches, some of these are quite good for signals.
You mention a 1G Zin requirement, what about I_leakage
and capacitive-loading specs, anything there?

What are you working on?

 

[GravityPoet]

There's also the possibility of using optically-switched
MOSFET switches, some of these are quite good for signals.
You mention a 1G Zin requirement, what about I_leakage
and capacitive-loading specs, anything there?

What are you working on?

This is an input circuit to a general purpose data acquisition board.
The output of the analog multiplexer is buffered with a voltage
follower (AD8512) in order to meet input requirements of 1GΩ input
impedance and input leakage
< 0.5µA.

The output of the voltage follower then feeds a level shifter/
attenuator ckt that differentially drives a 24-bit ADC.

Thanks for the help.