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Switch selection for +/- 8V square wave with 20kHz frequency

Other Parts Discussed in Thread: TMUX6119, TMUX6104, TMUX6136

Hello everyone, I want to choose a switch to achieve the following functions:


1. S1 is connected, and S2, S3, and S4 are grounded.

    S2 is connected, S1, S3, S4 are grounded. 

    S3 is connected, and S1, S2, and S4 are grounded.

    S4 is connected, S1, S2, S3 are grounded                   (switch switching frequency is greater than 10KHz)


2. The signal source is a square wave with amplitude of ±5~±8V and frequency of 10-20KHz.


3. Select STM32Fx series control switch on and off, so the address code terminal high level is less than or equal to 3.3V.


4. There is no requirement for the supply voltage and package form of the switch. There is no special requirement for the temperature range, and there is no special requirement for noise resistance.

There are two ways to connect to ensure that when one switch is closed, the remaining switches remain grounded, as shown in Figure 1 and Figure 2.

Figure 1 shows the single-pole double-throw switch at switch S. (Single-pole double-throw switch is grounded on one side and connected to the signal source on the other side)

Figure 2 shows the use of two types of analog switches, one of which is: one switch closed in n-Channel Analog Multiplexer, and the n-1 switch closed in n-Channel Analog Multiplexer at the same time.

So ,I have some questions as described following:


1. Whether the TMUX6119 can meet the above requirements for the single-pole double-throw switch connection method.

2. Is there any other types of single-pole double-throw switches can be selected?


3. For the connection method of Figure 2, the n-select 1 switch can use 74HCT4051 (of course, its high level is 5V).

But how to choose the analog switch whose n-Channel switch selects the n-1 Channel closed at the same time?

thank you very much!


            

 Figure1   Single-pole double-throw switch                               

  Figure2   Two types of analog switches 

  • user5994204,

     

    I would use the TMUX6104 device which will support +/- 8V signals @ 20kHz and you can set the A0 and A1 pins to select connect the signal to one of the 4 outputs.  Adding a weak pulldown on the out will ensure that the node is not floating when the TMUX6104 makes the device unselected signal path high impedance.

     


     

    Thank you,

    Adam

     

  • Thank you ,but  what I want to achieve is that the switch is not grounded when it is connected to a signal source. This switch is grounded at the same time as the signal output, so it does not meet the requirements.

  • User5994204,

    The 1M pull down is vary weak.  With 8V/ 1M = 8uA of current going to ground.  What are you connecting to that node where 8uA of leakage makes an impact?

    You could use 4x TMUX6119 that are 2:1 1-channel devices instead.  Also, 2x TMUX6136 that is 2:1 2-channel device.

    Thank you,

    Adam