[sdiy] Making a 4066 deliver negative signals

[Theo]

Have to agree with Michael.
Some series like Philps HEF or On semi MC are speced to work at 18V but its
is about their limit.
You need a pull down resistor (100k? as your on batteries) to negative
supply and a series diode in the control lines, if you do 0V-5V control
signals should work ok.
You may want to consider 4053 switches (or 4052,4051) little bit different
functions but these have separate logic and negative analogue supplies so
the pull down and diode are not needed.

HTH
Theo


----- Original Message -----
From: <WeAreAs1 at aol.com>
To: <_nial_ at yahoo.com>; <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, September 08, 2004 3:31 AM
Subject: Re: [sdiy] Making a 4066 deliver negative signals



In a message dated 9/7/04 6:14:39 PM, _nial_ at yahoo.com writes:

<< Hi all, newbie question; how do i (can ì?) make a 4066

deliver negative signals? Just connecting VSS to -V

instead of GND? I've got a +-9v supply (batteries),

this would make a total of 18vpp, would this fry the

4066? And last, would i have different levels for HIGH

vs LOW on the inputs? >>

Most people use a dual 7.5 volt supply to do what you are proposing.  You
very well might be able to run that 4066 on +/- 9 volts, or maybe it will
fry.
I've seen them operating on +18 volts before, but I think that's right at
(or
over) the spec limit.  Why don't you just try it?  4066's are cheap.  If it
doesn't work, you could build a simple little voltage divider with resistors
to
derive the +/- 7.5 volts from your 9 volt supplies (unless you feel
compelled
to use a couple of regulators).  There are also 4066-type switches from
Maxim
that can handle much higher bipolar signals and supply voltages, if you want
to
spend a little more money.

Michael Bacich