Table 2 of the data sheet (on page 13) gives several options for Power Down behavior which can be selected by serial programming. All of these options have DB12 high (12th bit of the 16 bit serial word).
I believe this table tells us the DAC behavior when #PD goes low - when we enter power down. The data sheet is not clear about this.
Or is the Serial Power Down command a separate way to get into Power Down than the #PD pin? If so, where is the behavior caused by #PD defined?
If we have previously written data to the device with DB12 = '0', which is required in Table 1 for all serial programming of the DAC in normal mode, and we have not yet written the Table 2 configuration information, what is the default behavior of the DAC in power down (Hi-Z, 1k, 100k on Channel A, on Channel B, both?) The data sheet is silent about the default mode. Do we enter Power Down at all if the serial condition is not programmed? Could the part be confused or damaged?
We have not been writing this 'serial power down configuration' at all, but have been asserting #PD. Two DAC7552 devices on two separate boards have failed after working for a while, for no apparent reason. Other boards have not failed.
Do we need to write the Power Down configuration serial command every time we want to assert #PD, or just once?
