Now April 2012
My problem is shown in http://ez.analog.com/thread/9318
But I can't understand the problem is gone in a new revision of chips.
We had an issue with the voltage references that control the Under Voltage LockOut, and set the regulation point. We made changes to the band gap circuits to ensure proper startup under all load conditions. The ADuM640x parts are the last parts to get the updated silicon due to other changes that we implemented in the part. The new silicon is in production and working its way through the distribution channels. If you have chips in your possesion right now, they are likely pre fix material.
How can I recognize the new silicon?
The ADuM640x series with date code of 1209 or later is the new silicon.
We couldn't get the ADuM640x series with date code of 1209 or later.
Now we can redesign our target board.
Can you say the problem for the ADuM640x series with date code of 1209 or later is gone?
Russian ADI specialist say us that the problem don't be gone. And they suggest us to use other ADI chips. But other chips don't satisfy us. So we must reject the ADuM640x series and start to use the ADuM440x series and power modules of other manufacture (for example TracoPower).
My records indicate that these issues were fixed in material newer than date code 1209. If you are having restart issues with material after that date code, please return the material for evaluation through your local distributor. Please note on your return that the failure analysis should be coordinated with the product line.
What is the date code of the parts you are having issues with?