We just completed a design with the UCD9240 (80-pin version) and we are in the testing stages. The design is as close as being 'by the book' as it gets with the caveats that the documentation is not consistent with respect to the connection of some pins (e.g., leave floating, or connect a resistor/capacitor to them). We have used development board schematics (from TI and XILINX) to resolve those inconsistencies.
The power good signal (on the power good pin) is not behaving as advertised, we have tried all possible configurations to no avail.
What we need it to do is to be an open-drain output that is active high. That is, actively grounded during start-up and passively raised after supplies are stable.
We can get it to actively drive the pin in this manner, but as soon as we configure it as open drain we get either signal inversion or some signal transitions that make no sense. There is no configuration that would achieve what we need it to do.
I can't see any notes regarding this in the erratas either.
Before we have to patch our prototypes, and modify existing designs in the pipeline to achieve this, are there any suggestions?
