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ADV7125 RGB to VGA output

Category: Hardware


I need to convert the  24 bit parallel RGB interface for a TFT panel  (output of a TFP401A) into a standard VGA interface.

Is ADV7125 suitable for this purpose? In such case, could I replicate the analog output section of circuit note CN-0282 to get the VGA signal?

Can I reach 1080p and WUXGA@60Hz resolutions using the 170 MHz version of this DAC?

Can MAX14984 be used between the ADV7125 analog outputs and the VGA connector in order to implement a monitor detection functionality?

Thank you


    TFP401A -> sending out odd/even pixels + clk + syncs. The ADG7125 is a DAC - takes in the odd/even pixels, then sends out analogue representation at the output to MAX14984. The MAX14984 should receive the syncs from TFP401A.

    The odd/even pixels are pixel positions per every video line. 1080p60Hz is 148.5 MHz without reduced blanking. The WUXGA should be similar or slightly more, since no timing details provided in terms of HxV total, it is hard to guess. If using the 170MHz speed grade of ADV7125, keep the pixel clock frequency lower. You could send on your application diagram details outlining what you are interested in doing so that it gets the correct support from the Video Group. Be careful here that you are dealing with some high-speed signals and due diligence is required. Consult the CN-0282 as you are trying to introduce another component in the path of the signal chain.

    If you provide the WUXGA timing spec/ the end monitor display timing spec, I could possibly help you to reduce the pixel clock frequency further if you application permits it.

    Why don't you use the ADV7611 in place of the TFP401A?



  • Hi edo,
    1080p@60Hz will be enough for our application, I asked about WUXGA because TFP401A is capable of such resolution, but we won't use 16:10 monitors in this project, so we can forget this last requirement.
    Here is a block diagram of our application. The purpose is to convert a Displayport++ into a VGA. I know that there are some ICs that do directly this job, but unfortunately they are phasing out and we need an alternative.
    The idea is to configure the DP++ source in DVI mode by making it believe that there is a source-side cable adapter connected to it, as per VESA interoperability guidelines. Then convert the DVI signal to VGA.

    The purpose of the microcontroller, as in CN-0282, is to filter the EDID content from the resolutions not supported by this converter.
    About ADV7611, this is the part that we did initially select for our application, but when we asked for support about it, we received the following alert by AD's central applications:
    You must be an HDMI adopter to buy any part which is HDMI capable.
    Since this constraint is on the purchase of the component, I guess that we could not buy it regardless of the use we would like to make of it. In this case we need a DVI receiver. TFP401A does this work and is not HDMI capable. I did not find a DVI-only receiver in AD's portfolio.

    In any case, we are open to any suggestions that can simplify the above diagram, keeping in mind that all the components used must be available with extended temperature range (-40/+85°C)

    Thank you