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CD4051B: If Pin 7 VEE of CD4051B is connected to GND at all the time, can I support 12V signals?

Adam Torma
Mastermind 45370 points
Part Number: CD4051B
Other Parts Discussed in Thread: TMUX1308

e2e, 

Q1 If Pin 7 VEE of CD4051B is connected to GND at all the time,CD4051B can be used for following usage below?

 

To control 8 external devices by one MCU in main unit, require MUX

Required MUX only use Triger signal and so quick changing speed is not required.

 require withstand voltage 12 V and so planning to use CD4051B instead of new 5V TMUX1308 device.

 

CD4051B can be used for this application?

Q2 About function of PIN 7 of CD4051B

 

According to TMUX1308 DS,PIN7 of TMUX1308 is N.C

https://www.tij.co.jp/product/jp/TMUX1308?keyMatch=TMUX1308&tisearch=Search-JP-everything&usecase=GPN

 

How is PIN7 of CD4051B like?

PIN7 of CD4051B is also N.C.?

What is the fundamental function of PIN7 of CD4051B.

Q3 Do you have any other optional MUX with 1:8, 12-V MUX?

Thank you,

Adam

  • 0
    TI__Mastermind 46427 points

    Hi Adam,

    Q1. Yes the CD4051B can withstand a single supply voltage of 12V. 

    However, what are the load conditions of the output of the Multiplexer. You mentioned 8 external devices that are being controlled by the MCU. Are these digital inputs?  If they are digital inputs with a high input impedance I don't think you will have much issue passing voltages through the parts. If this isn't the case please let me know to see if this part will work for the solution. 

    Q2. Pin 7 of the CD4051B is reserved for the VEE input. In bi-polar operation this is set to the negative supply rail, and when in single supply operation this pin is connected to GND. This is different from the 1308 because the 1308 doesn't support bi-polar operation while the CD4051B does.

    Q3: We do have a few options when it comes to 8:1 multiplexers that can handle a 12V single supply; please see this link here to see our options! If you have a few more details about the application that you can share such as signals being passed (Signal Levels, Frequency) and loading conditions of the device, as well as the purpose of the signals I might be able to find a better suited Multiplexer than the CD4051B for the application - however based on the provided information I do not see a problem using the device for this application.

    If you have any other questions please let me know!

    Best,

    Parker Dodson

  • 0
    Guru 271590 points

    1. VEE = VSS is allowed.

    2. Pin 7 is VEE and must be connected. VSS is the ground for the digital inputs, VEE is the negative power supply for the analog signals.

    3. Other 1:8, 12-V muxes are more expensive.

    Are the trigger signals actually 12 V? Are the control signals (INH/A/B/C) 12 ?