Go Down

Topic: 4051 multiplexer - difference between gnd and Vee? (Read 750 times) previous topic - next topic

lemming

I am looking at using a 4051 and read that you just connects E, Vee and gnd together for normal usage.

However, being curious, I would like to understand the operation of the chip in case, in future,  I have a use that could take advantage of the "Vee feature" (if it has an addition use other than being there just to tie to gnd).

Does anyone know what its other uses are?

P.S. Can anyone give a summary of what all the V?? notations mean. (e.g. the difference between Vcc and Vdd). I've see Vcc, Vdd, Vee and Vss.

Nick Gammon

Does this help?

http://encyclobeamia.solarbotics.net/articles/vxx.html
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

lemming

Thanks Nick. That's spot on!

Any idea why they bother with separate Vee on the 4051 rather than just tie it internally to gnd and do away with the external connection?

Nick Gammon

From the datasheet:

Quote
For example, if VDD = 5V, VSS = 0V and VEE = ?5V, analog signals from ?5V to +5V can be controlled by digital inputs of 0?5V.


So, it lets you control below 0V.
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

lemming

Thanks again Nick. My Texas Instruments datasheet does not have such a description. Whose datasheet are you looking at? It sounds more helpful than mine.

I gather that in such a situation (where the device connected to the analogue inputs has a range of -5 to +5 volts), the gnd of the device would be connected to Vee and the ground of the Arduino would be connected to gnd. i.e. the Arduino and the device would not share a common ground?



Nick Gammon

I looked it up at Element14 site.

I don't know about the second part of what you said.

I'm no great expert in working with negative voltages, but I would have thought you would need a dual power supply (ie. +5 and -5V) and connect both of them up to the chip (plus Gnd of course) and then share the grounds.
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

Go Up