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VPSS driving capacity of DM8168

Kai Ji
Prodigy 120 points
Other Parts Discussed in Thread: TFP410, SN75LVDS83

Hi,

We are planning to use one video output port(VOUT0) in dm8168 to supply to two external display terminals,  the interface for two display terminals was different, one is the LCD LVDS, another is the DVI port.  the two display terminals are using the same source which is the VOUT0 in RGB888 format.   the LCD LVDS will use SN75LVDS83 as its hardware driver to do the parallel-to-serial conversion, the DVI will use TFP410 to do the conversion.  my question is whether I can connect the input of both SN75LVDS83 and TFP410 to the output of VOUT0 in dm8168.   I am little concerned about the load capacitance of the VOUT0 in DM8168 and I didn't find any detail information about this parameters in the spec of DM8168.   the input capacitance for SN75LVDS83 is 2pF, the input capacitance for TFP410 is unknown from its spec.   can I just wire the Video raw data output include the vout_clk to two different driver interface: one is the LCD LVDS transmitter(SN75LVDS83) and another is the DVI transmitter(TFP410).

Thanks,

Karl

  • 0
    TI__Mastermind 25055 points

    Karl,

    A mux would not be required, but perhaps a buffer.  Muxes are for input selections, not output drivers.  It will depend on what the required pixel rate is. For 165MHz it might be needed but for 75MHz it might not. There is not really a ‘max’ load capacitance since it simply affects the slew rate of the outputs.  There isn’t really an easy way to determine if it is really required other than perhaps IBIS simulations, but I couldn’t see IBIS models for the TFP.

    Regards,
    Marc

  • 0 in reply to MarcPyne
    Prodigy 120 points

    Thanks. I got your point. our display resolution is 1024X768. I think it is under 75Mhz.