You can still use the 4066 as a digital switch by connecting VSS to ground, its only for some analog signals it needs the negative supply. If you are using it for analog signals, it may still be possible to use a single supply if you offset the input voltage to 2.5V. The important factor is that the input voltage does not go below ground (negative with respect to gnd). The idea behind the + and - supplies is that an AC coupled signal or one ground referenced can pass through the switch and still have +/- excursions at its output pin.
There are good reasons for using both supplies if it is necessary, the switch's 'on' state resistance gets lower as VCC to VSS become greater and the linearity also improves. The current drawn from the negative supply is very small so you can easily generate it from the positive supply using an oscillator and rectifier or you can purchase ready made DC-DC inverter units.
Brian.
I've successfully used the R05B05 from RECOM: datasheet download. It's small, already filtered, even 2 isolated ± voltages (what you wouldn't need). Got it for small money via eBay (search for DC-DC).... do you know what is the product code of DC-DC inverters?
Not quite right. To work with regular logic input levels, VSS has to be connected to 0 V. The terminal name "VSS" is common to all standard CMOS ICs, by the way. I guess, you need a negative supply because the analog signal is swinging below ground. But then, you'll also need a level converter for the logic input. Most people prefer analog switches with separate VSS and VEE terminals, e.g. 405x, in this situation.This type of IC does not work like a normal IC with pins 8, 16 connected to GND and VCC respectively, but it connects to VSS and VDD.
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VDD is ok since it gets the normal +5V but VSS must have -5V so that the IC works. I tested and it does work only with these condition.
According to the datasheet, a CMOS IC (e.g. HCF4066) supplied by VDD=+5V VSS=-5V has a VIL (input logic low level) of -2V, thus it can't be driven without a level converter. 405x or 74HC4316 can be driven by standard logic level.Are you saying than that the switch when it is 0 is not read a low, it has to be equivalent to the vss??
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