SN75DP130: SN75DP130: 10% of parts in production fail to initiate video after power up

Hi,

Unfortunately there is no software workaround. The HPD_SNK needs to come up after the RSTn has been released. This is to ensure the internal digital gets stable power first.

Thanks

David

Hi David,

   We have another question on this topic.  Akiva found that our design does not comply with the SN75DP130 Power Supply Recommendations regarding the power-up sequence.  In our design, on power-up, Vcc is applied before Vddd.  Power is coming from a pair of TPS54325 buck converters.  I changed the soft start capacitors so that the Vddd power-up occurs before the Vcc power-up.  After doing this, a board that was failing to output video an average of 9 out of 10 power-up cycles correctly provided video on 10 consecutive power-up cycles.  Now we are curious if only changing the power-up sequence would be an adequate fix to correct the issue of the DP130 registers not always initializing correctly with a powered monitor.  Will it still be possible for the DP130 registers to initialize incorrectly if the power supply sequencing is fixed?  Please advise us on whether it is advisable to still prevent the HPD_SNK from being powered before the chip is powered and reset is released if we fix the power-up sequence.  I think we should fix the power sequencing either way but would like confirmation on that too.

Best Regards,

Kennon

Hi,
Your issue is being reviewed by the appropriate engineer. Due to the New Years Holiday there may be a delay in response to your post. We apologize for any inconvenience.

Hi,

You would need to follow the power sequence in the DP130 datasheet. Please give me couple days to confirm with our design team whether HPD_SNK requirement still applies if the proper power sequence is being followed.

Thanks

David 

Hi David,

   Have you been able to confirm whether the HPD_SNK requirement still applies?

Thanks,

Kennon