(I attached a photo of the datasheet) I'm having a hard time understanding it, I'm new to this. I have a multiplexer that switches when I give it 7,5V, I want it to switch at 3V.
Currently VDD = 15V, VEE = -15V. Should I change it to +-5V?

 

Another photo.

 

What is the ic number?

 

(I attached a photo of the datasheet) I'm having a hard time understanding it, I'm new to this. I have a multiplexer that switches when I give it 7,5V, I want it to switch at 3V.
Currently VDD = 15V, VEE = -15V. Should I change it to +-5V?

Based on the test values shown, the multiplexer may not be intended to work with 3V. Unless you can provide the IC number, your question cannot be properly evaluated and answered.

 

What is the ic number?

cd4051be

 

cd4051be

The supply voltage for that MUX needs to be 3V if you want the logic levels to switch with a 3V signal.
Otherwise you could use a comparator, such as an LM339, to convert the 3V logic signal to a 15V signal at the output.

 

Also, what do they mean with "input low voltage" and "input high voltage", do they mean the input voltages VDD and VEE (15V and -15V)?

 

I have a multiplexer that switches when I give it 7,5V, I want it to switch at 3V

Do you mean that when the input signal from 7.5V drop to 3V and the switch enable(INH) is on and the input 3V will be output to output pin?

The CD4051 can't check how much voltage in the input pin, if you want to do that then you need to add a comparator as LM393, LM339 or and op amp LM358 to do the voltage comparing job for the input pin and when the input voltage drop to 3V and the output of comparator will send a low to INH to enable the output function.

How is the 7.5V?
Is that a sine wave 7.5Vpp as +3.75V and -3.75V or 15Vpp as +7.5V and -7.5V?
For 7.5Vpp then you will need ±5V power, For 15Vpp then you will need ±9V or ±10V power

 

It's not a sine wave. I'm bad at explaining but the input voltage is +-15V. Then I give the MUX, for example, 5V. The MUX has 3 digital input, and depending on which ones are connected to ground and which ones I "feed" a voltage to there will be a output voltage of 5V, however the output voltage doesn't show unless I "feed" the MUX with 7,5V, and we need it to appear when we give it 3V.

 

The cd4051be maximum total supply voltage (V+ to V-) is 20V so it can't be safely connected to ±15V.
What is the maximum plus and minus signal voltage?
That would be the supply voltages you need.

 

I might've used the wrong name for the +-15 voltage.
(See attached photo)
Vdd=15V
Vee=-15V
A, B, C is digital inputs.
Then there's 5V (for example) in one of the channels from 1-7 depending in which of the digital inputs I use.
I have to give the digital input at least 7,5V (I want it to be 3V) for it to show the 5V in the output.
Sorry for the confusion.

 

The Vmax power of CD4051 that you can apply it as 0~20V or ±10V for the +Vdd and -Vee(see the first page).

When the input was not the sine wave which only the voltage from 0V to Vmax 10V, so you don't need the power for -Vee, for the normal application then you just connected -Vee to Gnd and apply the power +5V, there is no needs the -Vee.

If you apply the +Vdd and -Vee with +5V then the digital input needs to apply at least +4.5V(see page 15), but if you apply the +Vdd and -Vee with ±5V then the digital input maybe can be apply only +3V and the INH is the same.

 

I might've used the wrong name for the +-15 voltage.

No, that's the voltage I'm taking about, that can't exceed a total of 20V.
If the maximum signal input is 0-5V then the mux supply can also be 5V.

 

If the maximum signal input is 0-5V then the mux supply can also be 5V.

That will limited by the digital input when the TS trying to apply it only 3V, and that was what I wrote at the last sentence in #12