AnsweredAssumed Answered

Vsync glitches on AD9880

Question asked by Colin.L on Jun 14, 2012
Latest reply on Jun 19, 2012 by GuenterL

We are using AD9880KSTZ-150 in a design and noticed glitches in the Vsync and video data outputs at 1080p60. Hsync output seems clean, as PLL should be locked in fine. A few things seem to be helping to reduce the glitches:

 

1. If we run at 720p60, there is almost no glitch.

2. The glitches seem to be related to temperature. The chip surface temperature is around 50C when we run 1080p60. If we spray cold air to the chip, the glitches disappear when the chip stays chilled. Also, a simple copper block on top of the chip seems to do the same.

3. Following a previous forum discussion, we modified register 0x53 from 3B to 2B, that seems to help reducing a lot of glitches.

 

We experimented with other PLL registers, none of which seems to help.  Also, we tried to increase the 1.8V and decrease the 3.3V supply voltages following the suggestion from a previous forum discussion, that did not seem to help either.

 

These glitches cause disruption in video synchronization, so any help in removing them would be much appreciated.

 

Colin

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