Analog switch

[neocps1]

Hello,

Do you know if the CD4066 analog switch handles negative inputs ? I mean, output for example -5V
when the switch is on and 0V when it is not ?

The datasheet is unclear about that.

thank you very much !

 

[alec_t]

Fig 4 of the datasheet shows switching of an AC signal. If your input signal goes to -5V then the negative supply terminal (Vss) of the IC must be more negative, e.g. -6V.

 

[neocps1]

Ok, Basically, I want to build a circuit based on a 4066 analog switch which allows me to have :

- Output 1 : 5V ON / 0V OFF
- Output 2 : -5V ON / 0V OFF
- Output 3 : 5V ON / 0V OFF
- Output 4 : -5V ON / 0V OFF

Control lines should be 5V if ON and 0V is OFF

do you think it is possible with the 4066 with VDD set to 5V and VSS set to -5V ?

thank you !

 

[Mike odom]

No, that will not work. For Vin = off, you have to be less than 30% of Vdd-Vss (5 - -5 = 10, @ .3 = 3V, above vss = -2V with respect to ground... the data sheet shows 2V above Vss for guaranteed low).

However, fig 18 of the data sheet shows you can use a 4054 with Vdd = 5V and Vss =0V and Vee = -5V, and uses a 0-5V switch input to turn the 4066 on and off. This looks exactly like your application.

 

[neocps1]

Thank you very much !

 

[ChrisP58]

Take a look at the CD4051, 52 and 53. They are more optimize for negative signals through the switch, but the control lines are ground referenced.