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Tri state switch with LED indicator

Mateusz Kaluzny17
Expert 1065 points
Other Parts Discussed in Thread: SN74HC157

Hello dear Ti community.

I've got some questions related with tri state switching and 2:1 mux.

1. How can I build a tri state switch with a led indicator? I need something with pull up//pull down//float mode to control internal dac function (WM8741).
I know that I can use simple dip switch with pull up and pull down resistors but then I will lose LED.

So could you provide me some help how to do it corrctly?

2. Second question is about 2:1 mux, I need swtich for choosing SPDIF input (optical and coaxial) so I choose a NC7SZ157P6X? Is that chip would be good or should I pick something else?
Is there any way to add a LED indicator to it? To inform me about which source is active ATM.

3. Similiar to second question. I've got SN74HC157 chip. I'm using it for I2S switch.
How can I add a LED indicator to it.

So all those question are similiar, so I assume there will be common solution for it :)

  • 0
    TI__Guru 71516 points

    Hello Mateusz,

     The NC7SZ157P6X is an ON Semi device and as such Texas Instruments cannot comment or recommend any design advice.  

    As for the LED on the SN74HC157 , please provide further detail as to what the LED is to indicate; when will it be ON and when will it be OFF?  Since the SN74HC157 has four switches, do you want an LED on each switch? 

    Looking forward to more details,

    ~Leonard   

     

  • 0
    TI__Guru 71516 points

    Hi Mateusz,

      I have not heard back from you as to the details of what you are wanting to accomplish here.  Have you determined which devices will be suitable for this design?  Are you requiring an LED Driver in addition to a mux?  A block diagram could be helpful as well. 

    Regards,

    ~Leonard