Connecting a HC4053 to DOUT

[WickedBlade]

Hey guys,

I'm still a newb here, and for my project (PBEX+a) I would like to use a CMOS switcher, but I have almost no clue as to what and how.

I know that I'll have only 5V power supply to work with, so the CD4053 seems out (if I understood the datasheets correctly).

I've found another candidate, that would be the HC4053. This one seems to be working with lower voltages, so that might be a winner. But I don't know how to check that and how to design that part of the circuit.

Specifically:

the HC4053 wants a 'negative input voltage' (Vee), I'm wondering if feeding this with ground would work, possibly by supplying a fake, positive ground to pin GND. I was thinking of feeding 0/2.5/5V respectively to Vee/GND/Vcc. But I don't know if the switching inputs would still be happy with being wired to DOUT.

Of course I've tried to do some research on the forum, but couldn't come with good keywords. If anybody could give me some clue or, even better, a schematics, that would be much appreciated.

The datasheet can be found here: http://www.st.com/stonline/books/pdf/docs/7731.pdf

[seppoman]

you can connect both GND and VEE pins of the hc4053 to GND at the same time, that's no problem. But another problem I ran into is that the 4053 doesn't like being fed signal that is outside of the supply voltages. So as a normal audio signal is bipolar, you will need to feed -5V Vee to not damage the IC. Otherwise you could also use reed relays for signal switching, there are types with SPDT action, although not very common and a bit on the expensive side.

S

[WickedBlade]

Thank you for your help.

I guess that it's OK for me then, because I won't use it for signal routing, only for amp channel switching, where the signal is constant.

Just to make sure: this wouldn't be possible with a CD4053, or would it?

And another one that just occured to me, and I think I won't like the answer. Will all this still work if the signal that is routed is 12V (while the chip is fed with 5V)?

[seppoman]

12V will destroy the chip. Whether the "signal" is changing or constant is irrelevant. The CD4053 can stand higher signal levels, but only if you feed it with at least 12V, and that also means that the control port wants a 12V signal, so not much use for your application.

So your "signal" is always either 12V or 0V, right? Maybe you could establish a way to output these two states e.g. by using a simple transistor/pullup circuit (still you'd need a source of regulated 12V DC), and do all the decisions if the output should be high or low in software?

S

[WickedBlade]

Thank you. I feared as much.

Well I think I will save myself the trouble and use relays instead, they don't care if the signal is very different from what they are fed ;)

(12V was just an exemple, it may change depending on the amp I'm plugged into, which is another argument in favor of relays)

[WickedBlade]

Or maybe I could use some regular transistor instead?

As you may have guessed, I'm trying to reduce the cost, as relays are pretty expensive.

I've been doing some more research (I'm trying!), and it appears that depending on amps, the switching process is not the same. For instance, Fender amps provide a sine signal, which is then divided into its positive and negative side, and these 2 pilot 2 function switching.

Anyway, I've just stumbled upon a thing called "solid state relay" on mouser, and I wonder if that's not what I'm looking for. Only, I can't seem to find application examples, and I'm having a hard time deciphering the datasheet.

There is for instance the Sharp PR33MF11NSZF (datasheet) which looks promising. They wouldn't call them relays if they didn't share the proprieties I'm looking for with relays. Right? Or would they?