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SN75DP130: Display port behavior confirm for the TI parts

Alvin Su
Prodigy 10 points
Part Number: SN75DP130
Other Parts Discussed in Thread: HD3SS213,

Hi Sir,

According to some of manufactory process concerns, we discovered that our products missing the connections of display differential pairs.

We suppose the display functionality will fail, still the display output through SN75DP130 + HD3SS213 + HDMI level shifter(NXP PTN3360D) to HDMI port on DOS mode is normal.

The display appeared some noise by SN75DP130 + HD3SS213 to DP port on DOS mode with the same symptom of missing one differential data line.

We're serious about the different display output behavior when the display main link missing one data line connection.

By the way, there's another display port solution by SN75DP122.

The HDMI port has no display and the DP port appeared a lot of snowing display with the same graphics card which is missing one data line connection.  

Could you explain the display output differential with the digital display interface transmit shortage of one data line?

Regards,

Alvin  

  • 0
    TI__Mastermind 19720 points
    From what I understand in your post, you are driving your solutions("SN75DP130 + HD3SS213 + HDMI level shifter(NXP PTN3360D)" or the "SN75DP122" ) from only one of the differential pair lines connected with the other line floating or ground. The " SN75DP130 + HD3SS213 + HDMI level shifter(NXP PTN3360D)" solution is working but the "SN75DP122" solution is not working with snow appearing on DP but HDMI not working at all. Is this correct?

    If so then only having one diff pair connected causes the signal to be only half Vpkp compared to two diff pair lines.

    The solution of the "SN75DP130 + HD3SS213 + HDMI level shifter(NXP PTN3360D)" might be working because and the SN75DP130 might be close enough on the PCB to the source to redrive the signal to full Vpkp on the both the diff outputs of the SN75DP130 and give the other two chips a large enough differential signal to drive the sink(monitor) on DP and HDMI.

    The SN75DP122 might not be working because the device might be further away on the PCB causing the signal that is already only half Vpkp to be too small to redrive in an effective way. The reason why DP might be giving you a snowy image and the HDMI no image at all is because the HDMI is much less forgiving on having only one diff input than DP.

    Does this answer your question?