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DS90UH925/6Q Application

kevin hsu
Prodigy 70 points

Other Parts Discussed in Thread: DS90UH925Q-Q1, DS90UH926Q-Q1

Dear sir,

I am looking for high speed(>75MHz pixel clock for 720p ) serializer / deserializer chip  to transmation TUV422 format 16 bits data. Can DS90UH925Q-Q1 and DS90UH926Q-Q1 (24 bits) support it? If it cans which data pin should I connect? 

  • 0
    TI__Intellectual 2855 points

    Hi Kevin,

    Another SerDes pair - DS90UB913Q and DS90UB914Q might be more suitable to your color space and bus width.

    In principle the UH925/6 can support it. Which pins you use may depend somewhat on your application and whether other features are to be used (I2S audio, GPIO, etc). Could you tell us some more about the application? 

    The 925/926 comes in UH (HDCP enabled) and UB (non-HDCP) versions. Does your application require HDCP support? If so, you would need to register and become and HDCP adopter through DCP, the licensing body for HDCP technology.

    Thanks,

    Ryan

  • 0
    TI__Prodigy 175 points

    Hi

    Yes the DS90UB913/914Q chipset is more suitable for this application. You can contact me at amritraj.khattoi@ti.com for additional information regarding this chipset.

    Raj

  • 0 in reply to Ryan Bailey
    Prodigy 70 points

    Dear Ryan,

    Thanks for your reply. The reason why I need to use  DS90UB913Q and DS90UB914Q is pixel clock. My project need to support 720P. That means the pixel clock is approach 75Mhz and only  DS90UB913Q and DS90UB914Q can support it!

    Kevin!

  • 0
    Prodigy 70 points

    Dear All,

    Sorry for my mistake in last mail. I want to tell you about data bits not pixel clock. I use this chip to transmation 16 bits YUV422 data. Only  DS90UB913Q and DS90UB914Q can support more then 16 bits and >75MHz pixel clock data in SDI interface!

    Kevin

  • 0 in reply to kevin hsu
    TI__Prodigy 175 points

    Hi Kevin

    The DS90UB913/914Q can only support 12 bits up to a PCLK frequency of 75MHz and 10 bits upto a PCLK frequency of 100MHz. For a 16 bit wide data you need to use the DS90UB925/926 which supports a 24 bit color depth up to a PCLK frequency of 85MHz.

    Raj

  • 0
    Prodigy 70 points

    Dear All,

    Thanks for reply!  Let's go back to my second question. DS90UH925Q-Q1 and DS90UH926Q-Q1 is 24 bits and our request is 16bits, so which part should I connect(Ex. R&G, G&B B&R). Also what should I deal with for non connect pin(Ex. Pull high/low or float)?

    Thanks!

    Kevin

  • 0 in reply to kevin hsu
    TI__Intellectual 2855 points

    Hi Kevin,

    Any combination would be acceptable. However, for maximum flexibility I recommend distributing your video bits across the six (6) most significant bits (MSBs) of each color channel. This includes R[7:2], G[7:2], and B[7:2]. The reason for this is that the two least significant bits (LSBs) of each color channel are shared with I2S audio and GPIO pins - depending on your design you may want to use them now or in the future. For example, you might use R[7:2], G[7:2], and B[7:4].

    Unused inputs may be pulled low. I recommend a kOhm-range pull-down but connecting directly to GND is also acceptable. You might also consider placing the device in 18-bit mode so that the 2 LSBs for each color channel are ignored by default. 18-bit mode is also required if you intend to use I2S_B or any back-/forward-channel GPIO options.

    Thanks,

    Ryan

  • 0
    Prodigy 70 points

    Dear Ryan,

    Thanks for excellent explain for those information that is exactly what I need. But one more question. Basis on datasheet the data pin should be leave if unused. It looks conflict to you suggestion? Can you help me to explain more?

    Thanks!

    Kevin

  • 0 in reply to kevin hsu
    TI__Intellectual 2855 points

    Hi Kevin,

    You are correct - the RGB inputs do have internal active pull-downs, so you are not required to implement it externally. However, it's reasonably good design practice to tie the unused pins low if the design permits it.

    -Ryan

     

  • 0
    Prodigy 70 points

    Dear All,

    Thanks for your reply. I have no more question in this issue.

    Thanks!

    kevin

  • 0 in reply to Ryan Bailey
    Prodigy 70 points

    Dear Ryan,

    Thanks for help!

    Kevin