Help: Does a 40V multiplexer chip exist?

[thedude710]

Hello,
I have an input signal that is a square wave that oscillates at ~170kHz with a low of 0V and a high of 40V. I would like to use a de-multiplexer chip to take this input signal and send it to an output of my choice. Is there any de-multiplexer chips that can do this? It needs to be small and light weight. If not, can anyone think of another way of doing this? Thank in advance.

 

[MikeMl]

How many outputs? Maybe you could use some 100V MosFETs and build your own.

 

[thedude710]

Hi MikeMI,
I will end up needing ~20 outputs. I was considering putting a few 4 or 8 channel mux in series to get this number of outputs. I think I actually found a mux that will work for me...
https://www.electro-tech-online.com/custompdfs/2009/11/MAX14752-MAX14753.pdf

What do you think?

 

[MikeMl]

Can you tolerate the 60Ω ON resistance?

 

[thedude710]

I don't understand what the On resistance is. Does this just mean that there will be a voltage drop across the chip? The current need is only about 10mV so if the resistance across the chip is 60ohms then there will only be a ~1V drop which is fine. The biggest concern I have with this chip is it say that under normal operating conditions the current on any channel shouldn't exceed 5mV but at the top of the data sheet is mentions something about max current being 100mV. I need to pass ~10 to 20mV through a channel. Do you think this will be fine? (The data sheed mentions 5mV per channel in the "applications information" section need the bottom. Your help is greatly appreciated!!!

 

[blueroomelectronics]

What is the chip? What are you trying to build?

 

[ronsimpson]

Use relays.
Use solid state relays.

 

[thedude710]

Hi Bill,
The chip I found that hopefully will work is MAX14752. As I mentioned above, my concern is the current passing through the chip. The input and output current will be around 10 to 20mV but there is a paragraph in the data sheet that says:

"The current flowing through each on-channel of the
MAX14752/MAX14753 multiplexers must be limited to
±5mA for normal operation. If the current exceeds this
limit, an internal leakage current from that channel to
VSS appears. Larger input current does not destroy the
device if the max power dissipation is not exceeded."

On the top of the data sheet it says the max current for input and output is 100mV though. I am not sure of the difference.

What I am trying to build is the following:

I have ~20 very small motors that are powered by a square wave 40V, ~170kHz power supply (actually they are each powered by 2 out of phase square waves but this does not matter for the time being). Only one motor needs to be powered at one time so my idea is to use only one power supply and choose which motor to power by using a multiplexer acting as a de-multiplexer.

 

[mneary]

If your output is 10 to 20mV, this is a lot less than 40V. What is the real signal?

 

[thedude710]

Whoops, I meant 10 to 20mA. Amps not volts. Thanks