[sdiy] Using the VEE pin on a 405x Multiplexer

[Elby Designs]

I thought the ruling was that the difference between Vee and Vdd must not be
greater than 18V. By setting vee and Vdd you then determine what signal it
will work with. So, if Vee=0V and Vdd=15V then Vin can be 0V to 15V. if
Vee=-7.5V and Vdd=7.5V then Vin can be -5V to 5V and so on.

Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Web: www.elby-designs.com


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Justin Owen
Sent: Saturday, 9 October 2010 3:26 AM
To: 'SDIY List'
Subject: Re: [sdiy] Using the VEE pin on a 405x Multiplexer

-----Original Message-----
From: David G. Dixon [dixon at interchange.ubc.ca]
Received: 08.10.2010 16:55:55
To: 'Justin Owen'; 'SDIY List'
Subject: RE: [sdiy] Using the VEE pin on a 405x Multiplexer

>> I'm trying to understand how to use VEE (Pin 7) on a 4053 Multiplexer.

>> My understanding is that I can apply a negative voltage bias to this pin
>> which will allow an AC signal to pass through (I'm hoping for approx. 10V
>> PP @ +/-5V) - all while powering it with +12V @ VDD Pin 16.

>> Can anyone confirm a) if this understanding is right, b) what the maximum
>> negative voltage is (is -12V OK?) that I can apply to VEE and c) is it
>> just one in, one out or is there some equation balance between VDD & VEE.

> The CD405x datasheet says it can handle signals up to 15Vp-p, and mentions
> specifically that VDD = 5V and VEE = -5V allows +/-5V signals to pass.
> However, under the Absolute Maximum Ratings section, it says the minimum
> input voltage is 0.5VDC.  These statements would appear to be mutually
> exclusive!

Well, I got bored and impatient so I plugged VDD: +12V, VSS: 0V and VEE:
-12V and I'm now running an 11.5V PP AC sine wave through it with no probs.

No smoke, no warmth on the chip (so far), as far as I can tell sine in =
sine out.

So there you go. If anyone has a reason why I shouldn't be doing this -
please chime in.

J


_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy