• Resolved

MUX solution for clock input

Dear Team,

Does anyone can help to find the solution which can support three 10 Mhz TTL clock input and 1 output? Just like below figure.

The MUX suggest to have low noise characteristic to make sure the input clock are not influence much by the MUX.

 Please help to recommend the component.

Thank you.

  • Hi Jim,

    You could consider SN74HC151, a 8:1 mux that supports TTL.

    Regards,
    -Tim
  • Jim,

    If you look at the switches and multiplexers search tool you can sort on 3:1 devices with >10MHz bandwidth.

    What do you think about the TS5A3359

    Thank you,

    Adam

  • In reply to Adam Torma:

    Hi Adam,

    Do we have the mux has zero delay feature? Since their spec requires the input to output delay is as low as possible.

    Thank you.
  • In reply to Jim CHEN:

    Jim,

    There is physically no such thing as 0 propagation delay through an IC.  Passive FET switches have very low propagation delays because there is no buffering of the signal and the delay is simply how fast the signal can propagate from the drain to the source of a single FET.  

    Many of our switches do not have this spec since it is assumed low but our newer switches like the TMUX136 do have this parameter specified in the 100ps range.

    What is the target propagation delay you need in your system?

    Adam  

  • In reply to Adam Torma:

    Hi Adam,

    Their spec needs nano second level of propagation delay. So I think the solution like TMUX136 pico second level should be fine.
    But TMUX136 is 1:2 switch.
    Could you help to recommend 1:3 switch?

    Thank you.
  • In reply to Jim CHEN:

    Jim,

    Passive CMOS FET switches have single digit ns to ps propagation delay.   The majority of that delay is due to the length of that path which the signal has to travel from one pin to the other.  The longest path in a CMOS FETswitch primarily the length of the metal leadframe (pin) and bondwire that attaches to the silicon die.  The actual silicon CMOS FET switch drain to source delay isn't significant compared to the delay due to the length of pins and bond wires of the IC.

    I have showed the 3:1 switches using the TI.com switch search tool which likely all have ns or less propogation delay.  If you want one that has prorogation delay specified in the datasheet you can look at the TS3USB3031.  

    Thank you,

    Adam