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FPD-Link-II/III Cable & Connectors for commercial application
I am currently using a FPD-Link-II (DS90UR905Q/906Q) chip set, and I am now looking to use a newer FPD-Link-III chip set in next iteration for supporting a WVGA (PCLK = 35 MHz; therefore 1.225Gbps) LCD as well as making use of the I2C and GPIO for a HMI application.
The application is for a commercial project and is cost sensitive; therefore I do not need automotive grade cabling / connectors or H/W. I did consider the commercial Channel-Link-III devices however there functionality did not satify my application requirements; therefore the FPD-Link-III Ser/Des (DS90UB925Q/926Q) was chosen as the most suitable device(s) despite the higher cost.
I'm currently using Belden EIA RS-422 cable 9729 (Which satisfies the 100 ohm differential requirements) but terminating this using standard Phoenix Contact 3.81mm pitch connectors for practical ease of use (I know 100 ohm connectors are recommended). I do experience intermittent loss of the LOCK signal particulally at higher PCLK frequencies when driving higher resolution displays, which I suspect is probably due to the incorrect connector being used. I have accessed the FPD-Link-II (DS90UR905Q/906Q) chip set with the specific Rosenberger HSD connector and cable assembly using Rosenberger mating connectors and Dascar_535 cable for which I did not see any loss of the LOCK signal.
The question is can anybody advise on the connectors / cabling that are best for use in a commercial application ? I have looked around and this seems to be a niche area for which automotive and military dominate.
Thanks in advance
Do you have S-parameter measurements for the cable you want to use (Belden EIA RS-422 cable 9729)? The most important factor with these devices is going to be related to insertion/return loss in the cable at the line rate of interest. My general recommendation would be to minimize insertion/return loss, and one of the first places you can do that is with a balanced differential connector. The LOCK issues you mentioned above could be due to this fact alone.
HSD connectors are very good for this kind of application. We have also seen mini-B style USB connectors. Even though USB is not 100ohm, the connectors are designed with a differential signal in mind (sort of), so this could potentially get the job done in a consumer application where distance and EMI concerns might not be as sensitive as automotive.
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