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TMUX1511: Using TMUX1511 for sensitive Clock applications

Part Number: TMUX1511
Other Parts Discussed in Thread: DS10BR150,

Hello,

we have an Jitter sensitive 25MHz LVDS Clock. The Clock-Source has different power-up timing and voltage source  than the Clock-Buffer on our Board. We need to achieve  a  "Powered-off" protection for the Clock-buffer.  We thought about using  DS10BR150 or TMUX1511PWR. Which device will add less Jitter to our Clock Signal? DS10BR150. The idea behind  TMUX1511PWR was that the quasi passive lead through will add minim Jitter to the LVDS Signal, although no Jitter Values are given in the Data-Sheet.

Best regards

  • Hey Dietmar, 

    I can't really speak on the DS10BR150 but i'll loop in the appropriate team for the analysis on that side, as this is the switches & multiplexer forum and our expertise isn't in buffer/repeaters

    From the TMUX1511 perspective, the jitter should be very minimal. This is just a passive device. Jitter can just be thought of as the change in the RC constant on the specific channel (side note, similarly skew would be the change between different channels). So here we would be interested in the variation in the on-capacitance and the variation in the on-resistance. The capacitance will remain fairly constant at 3.3pF. The variation in RON on a single channel can be thought of as the RON flatness, which is 1.8max in this device. This would be just 1RC. We would probably want to use 2xRC to get up to 86.5% on the rise/fall times. So this would give us 1.8*3.3pF*2 =~12ps. This is assuming worst case and across temperature. In normal conditions, I wouldn't expect much jitter at all. It's a passive device with pretty flat resistance and capacitance. 

    I believe our high speed signal chain team can provide more insight on the DS10BR150 to help your decision. Lookin at the datasheet, it does look like the jitter may be a little more here though.

    Thanks,
    Rami