CMOS Switch for -5, 10, and 5V

Question

Is there any way to make a switch that uses a 5V input to open a -5V or 10V connection? (so i can switch between making a line -5 and 10V).

Thanks in advance!

He doesn't seem to know how much current he wants to pass, and seems to want to use individual NMOS and PNOS transistors. — Leon Heller, May 02 '11 at 21:42
@Leon, you are very knowledgeable, but as our highest rep user, can you please try to be a bit more civil and inviting? I understand frustration with basic questions, but it would be better to phrase it so the user does not feel like they are being attacked or mocked. — Kortuk, May 03 '11 at 10:27
The question should be closed. He doesn't seem to know what he wants! — Leon Heller, May 03 '11 at 12:17
Use a 5V relay with changeover contacts (SPCO) if you need to pass a lot of current. — Leon Heller, May 02 '11 at 21:20

score 1 · Accepted Answer · answered May 02 '11 at 21:33

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Some switches like ADG733 have a separate Vss pin which can be at a lower potential than the logic GND; this means you could have a -10V supply on the Vss pin which would allow the gate to control up to a -10V signal whilst still having a 0-Vdd logic input. Unfortunately the ADG733 is limited to a 5.5V supply; but there are probably other parts that will do the same job (numbers escape me at the moment.)

answered May 02 '11 at 21:33

Thomas O

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+1 for Analog Devices. They have the widest selection of odd-voltage analog switch parts. – markrages May 02 '11 at 21:42
I want to do this on-chip, not using outside switches. – Cenoc May 02 '11 at 21:55
@Cenoc If so you probably want some kind of CMOS transmission gate. – Thomas O May 02 '11 at 22:09
There would be a problem with the biasing of the substrate diode if I do that, wouldnt there be? – Cenoc May 03 '11 at 02:04
@Cenoc only if current flows from anode to cathode. You are talking to a CMOS idiot! – Thomas O May 03 '11 at 06:49
The substrate is tied to Vss, which is always the most negative voltage to prevent forward-biasing the substrate/nfet junction. – W5VO May 03 '11 at 06:53

score 0 · Answer 2 · edited Apr 13 '17 at 12:32

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I'm not sure if you're asking for an analogue switch that can handle signals in the range -5V to +10V or a digital interface to convert a 0 to 5V level into a -5v to +10V level. If it is the latter, my answer to this question might help. This arrangement would work with N & P channel FETs with little modification.

edited Apr 13 '17 at 12:32

Community

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answered May 03 '11 at 10:19

MikeJ-UK

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I think he wants to connect something to either -5V or +10V, using 5V or 0V. – Leon Heller May 03 '11 at 12:16

CMOS Switch for -5, 10, and 5V

2 Answers2