TFP410: Cycling power and TX0+/-

Hi,

Does TX0+/- output come back if you lowered the temperature down to 25C? 

Is the TFP410 thermal pad soldered down to the board ground with at least 50% solder paste coverage.

Can you reach out to our local FAE to submit couple units for FA?

Thanks

David

Hello David,

It operates fine well past 50 deg C as long as you don't cycle power.  Once it fails it doesn't seem to come back at temperatures up to 5 degrees lower (~45 deg C) until you cycle power.  I'll try going down to 25 C after failure w/o cycling power tomorrow.

I haven't yet x-rayed the mounted parts, but am assuming 100% paste coverage before reflow and any resulting voids after reflow to be <50%.  Sounds like I need to confirm through x-ray.  3 CCAs all exhibit the same symptom.

Do you have a recommendation of an available local FAE?

Thanks for the quick response,

Rob

Rob

Please give me couple days to find the local FAE that will help you with the unit submission.

Thanks

David

Rob

Brad, our TI account manager for you, will reach out regarding the unit return process. 

Please follow our customer return process here: https://www.ti.com/support-quality/additional-information/customer-returns.html, and let us know if you have any questions.

Thanks

David

David,

I managed to correct the problem by issuing a reset and initialization of the chip when valid video is detected to be available to the TTL inputs after having not been valid (edge triggered).  Seems to be working under all conditions.  Any idea what would cause the total lack of activity of only one DVI channel (TX0)?  H, V, and DE related?  These are on this channel's inactive portion.  

Fingers crossed.  Thanks for your help. 

Rob

The three TMDS channels are used to transmit RGB pixel data during the active video interval (DE = High), and also also used to transmit HSYNC, VSYNC, and three user definable control signals, CTL[3:1], during the inactive display or blanking interval (DE = Low) as shown below.

So are you seeing the issue when DE is high (active video) or DE is low (blanking)?

Thanks

David

The TX0 channel, and only that channel, was completely inactive and at the low level during the entire time of active and inactive portions (DE high and low).

Rob

In your previous message, you said "I managed to correct the problem by issuing a reset and initialization of the chip when valid video is detected to be available to the TTL inputs after having not been valid (edge triggered).  Seems to be working under all conditions". But the initial issue is that when you cycle power at an elevated temperature of 50 Deg C ambient and case temp of 64 deg C the TX0+/- lines do not go active, what is the difference between the two setup?

Thanks

David

David,

The difference is instead of just performing reset and initialization on powerup, we wait until TTL input video goes from an invalid to valid state before reset/initialization.

Thanks

Rob

Rob

I think the invalidate state of the DVI source is confusing the TFP410 and causing problem with TFP41-EP TX0+/-. Once the data is valid and the TFP410-EP gets reset, the TFP410-EP will latch to the input side and in the correct state.

Thanks

David