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TMUX4051: Appropriate MUX for shut register

ttd
Mastermind 8050 points
Part Number: TMUX4051
Other Parts Discussed in Thread: TMUX4052, , MUX506, MUX36S16, MUX36S08, TMUX1072, INA186, TMUX7208

Dear Technical Support Team,

I'd like to configure 32:1+EN (output Hi-Z) using multiple MUX.
TMUX4051 and TMUX4052 are especially reasonable price.

Could you share the reason (for example spec)? 

MUX506
MUX36S16
TMUX4051
MUX36S08
TMUX4052
TMUX1072

www.tij.co.jp/.../compare.html

I'd like to change the shunt register value for current sensing with INA186A1.

Best Regards

ttd

  • 0
    TI__Mastermind 28088 points

    Hey  ttd,

    The table you sent was a sufficient resource for selecting a device but I can give more general differentiations.

    From a spec stand point these devices below are very similar and i'll group them together.

    MUX506
    MUX36S16
    MUX36S08

    These will be devices that go up to 36V or +/-18V. RON is a little higher relative to other muxes. 
    The MUX36xxx devices will provide lower leakage than the MUX506 so they will be better to use in systems where precision is more important.
    The MUX36S16 is a 16:1 vs MUX36S08 is an 8:1. Between the two, if you need to build a 32:1 the MUX36S16 x 2 will be better than using MUX36S08 x 4.


    The TMUX4051 and TMUX4052 won't have quite as high of a voltage support (up to 24V or +/-12V). They will have flatter RON but won't be quite as rail to rail (meaning that RON does increase when Vs approaches VDD or VSS) but very flat when not near the rail. TMUX405x devices will have a lower RON though than the MUXxxxx devices. Will also come in smaller packages but will also require more devices to build your 32:1 (for a TMUX4051 you would need 4). You could use the TMUX4052 as well but would require an extra mux since you couldn't isolated the A channel from the B channel on the 2 channel 4:1 if you were to tie the output together.

    TMUX1072 is a low voltage device. It won't support dual supply like the other two 'groups' of muxes. RON is significantly lower (6ohm) but does see a bit more leakage so if precision is something you're looking for, this may not work. It is also more of a protection device. When an overvoltage event occurs (~6V) the faulted channel goes to HI-Z and a fault detection pin is pulled low.

    Let me know if this sort of analysis is what you're looking for or if you can provide more information - Voltage and frequency range through mux, current passing through mux, concerns with any device - let me know and I can help narrow down a mux for you.

    Thanks!
    Rami

  • 0 in reply to Rami Mooti1
    Mastermind 8050 points

    Hi Rami,

    Thank you for your reply.

    Voltage:  -100mV～5V(MAX)　⇐ Dual Supply

    Frequency: Low (Near DC Voltage)

    Current passing through mux: IIB: 500 pA (typical) for INA186 because of high differential input impedance.  

    concerns with any device:

    I have a plan to select shunt register(like 1Ω and 100Ω ) with mux between shunt resistor and I’d like to select a MUX that does not affect the accuracy of current sensing.

    Then what parameters are important, such as Ron or leak current etc.

    MUX36S16 and TMUX4051 look good. If you have any recommend mux, please let me know.

    Best Regard,

    ttd

  • +1 in reply to ttd
    TI__Mastermind 28088 points

    Hey ttd,

    This application note may also be of some interest to you How to Handle High Voltage Common Mode Applications using Multiplexers. 
    Looks like figure 3-7 is closer to what you're attempting to do.
    While the supply is 5.5V on the current sense amp, it looks like the actual bus voltage is 40V so it seems you'll need a mux that can support up to 40V.
    For accuracy, the Leakage and the Charge injection would also be important. 
    The TMUX7208 may be a better fit here. It will have the low leakage, low charge injection and will be an 8:1 mux so you can build the 32:1 configuration easier. Also has an EN that you were looking for to help isolate the other channels when not selected.

    Let me know what you think
    Rami