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AD9889B and 1080p60 problem

Hello,

I am using an AD9889B,sucessfully transmitting 720p60 and 480p60 signals.

Now I tried to transmit 1080p60.

AD9889B corrently recognizes the mode that I send to it by reading these registers(R0x3D=0x10,R0x41=0xF8,R0x42=0x10,all circuits powered up and Hot plug active),but the display is black.I've tried many diffrent displays(samsung and others),all displays are black.

I modify R0xA2 and R0xA3 to 0X87,and change the timing sequence following EIA-CEA-861-D(verified with a scope),and using videoclock of 148.5MHz,but it's not working.

I've tried 1280*768 60Hz too,the videoclock of 108MHz,the display is sign good and black from time to time.

I am not using HDCP.

Any other regiter must be modfied?

many thanks

Tom

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  • Hi Tom,

    Yes -165 can run up to 165Mhz inputs.

    It sounds like you have issues with your PCB if you are seeing the clock degrade at the higher frequencies and lots of noise on PVDD.  You won't get the AD9889B to work with any settings in that condition.  I'd suggest adding bulk capacitance to try to quiet the power supply for PVDD-- is it isolated from the other power supplies.

    If you can increase the current drive on the VCLK from the FPGA, that might help as well. You might also need termination on that line.

    Dave

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  • Hi Tom,

    Yes -165 can run up to 165Mhz inputs.

    It sounds like you have issues with your PCB if you are seeing the clock degrade at the higher frequencies and lots of noise on PVDD.  You won't get the AD9889B to work with any settings in that condition.  I'd suggest adding bulk capacitance to try to quiet the power supply for PVDD-- is it isolated from the other power supplies.

    If you can increase the current drive on the VCLK from the FPGA, that might help as well. You might also need termination on that line.

    Dave

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