ARC termination circuits

The ADV7622/3 and ADV7511 have different ARC termination circuits. On the ADV7511, the coupling capacitors are in-line but on the ADV7622, the coupling capacitors are in parallel. Why is this?

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  • 0
    •  Analog Employees 
    on Apr 30, 2014 1:37 PM

    Hi Chetan,

    In-line answers below ...

    1. Pull-up or pull-down for HEAC+ and HEAC- signals? The eval board schematics suggests 49E9 pull down whereas the hardware user guide recommends 50R pull-up? Its conflicting! What should be default configuration? Please suggest.

    >> 50ohm is not a common resister size from our passive supplier. We selected 49.9ohm as it was more readily available to us. The 0.002% difference is unlikely to cause an issue for this termination.

    2. What is the purpose of D600 on AV0_CEC signal?

    >> It is a low leakage diode to ensure that the CEC network adheres to the HDMI Compliance Test Specification for CEC leakage. Please refer to the HDMI CTS.

    3. Is it recommended to have ESD protection on HEAC+ and HEAC- lines?

    >> We recommend ESD protection - it is shown in all of our reference designs.

    4. If I dont intend to use I2S, DSD port of ADV7511, and SPDIF IN, is it ok to terminate these pins to ground? Please confirm!

    >> For unused pin recommenations, please refer to the ADV7511 Hardware User Guide - http://www.analog.com/static/imported-files/eval_boards/ADV7511_Hardware_Users_Guide.pdf

    5. Whats the significance of the buffer U17 placed on the HDP line. I believe its just for an LED indication whenever a HDMI sink is detected.

    >> This is correct.

    Best regards,

    Joe

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  • 0
    •  Analog Employees 
    on Apr 30, 2014 1:37 PM

    Hi Chetan,

    In-line answers below ...

    1. Pull-up or pull-down for HEAC+ and HEAC- signals? The eval board schematics suggests 49E9 pull down whereas the hardware user guide recommends 50R pull-up? Its conflicting! What should be default configuration? Please suggest.

    >> 50ohm is not a common resister size from our passive supplier. We selected 49.9ohm as it was more readily available to us. The 0.002% difference is unlikely to cause an issue for this termination.

    2. What is the purpose of D600 on AV0_CEC signal?

    >> It is a low leakage diode to ensure that the CEC network adheres to the HDMI Compliance Test Specification for CEC leakage. Please refer to the HDMI CTS.

    3. Is it recommended to have ESD protection on HEAC+ and HEAC- lines?

    >> We recommend ESD protection - it is shown in all of our reference designs.

    4. If I dont intend to use I2S, DSD port of ADV7511, and SPDIF IN, is it ok to terminate these pins to ground? Please confirm!

    >> For unused pin recommenations, please refer to the ADV7511 Hardware User Guide - http://www.analog.com/static/imported-files/eval_boards/ADV7511_Hardware_Users_Guide.pdf

    5. Whats the significance of the buffer U17 placed on the HDP line. I believe its just for an LED indication whenever a HDMI sink is detected.

    >> This is correct.

    Best regards,

    Joe

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