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LMH0324: Switching speed of the input mux and latency of the device

Part Number: LMH0324
Other Parts Discussed in Thread: LMH0318, , LMH1218EVM, LMH1218, LMH1219EVM, LMH1219

Hi Team,

We would like to ask your help regarding the customer's inquiry below.

I'm planning on developing a HD-SDI 2:1 switch using 2 x LMH0324 and 1 x LMH0318.
The customer has a requirement of 16ms latency through the switch and a switching time between inputs of 160ms.
I cant see any relevant data in the datasheets for the LMH0324 and LMH0318.

1) What is the switching speed of the input mux on the LMH0318 ?
2) What delay/latency does the video signal experience when routing through the LMH0324 and LMH0318 ?
3) As the evaluation module for the LMH0318 is no longer available can I use the LMH1218EVM as an evaluation module for the LM0318, if so do I need to replace the LMH1218 device on the board ?
4) Similarly can I use the LMH1219EVM to evaluate the LMH0324, again by swapping the part? 

Thank you for your support!



  • Hi Danilo,

    1). When you switch from one input to the next, device needs to lock to the incoming signal. For HD-SDI it will take about 6mS to lock. The actual switch is in order of nano-seconds. Therefor we should be able to meet 16mS well with margin.

    2). Once LMH0324 is equalized and LMH0318 locked the delay through these two parts are within 2-3UI. UI(Unit Interval) is bit length at operating data rate.

    3). LMH0318 and LMH1218 are the same part. They are rated and tested at different data rate. For HD-SDI performance, these devices are the same. Therefor you can use LMH1218EVM to check HD performance.

    4). Same is true for LMH0324 and LMH1219. Please note we need to disable or bypass CDR function of the LMH1219 and operate the device at HD rate.


  • Hi Nasser,

    Thank you very much for your quick response.