We have just received a new series of our TAS5630-based boards and observed the /SD mostly is active at power up (and stays in /SD mode).
When the power is cycled the most common is the /SD is active, second common is the READY active. Ones in a while neither /SD or READY is active.
The TAS5630 is hold into reset until the power is stable, as described in the datasheet. The TAS5630 rarely escape the /SD-state if another reset is introduced.
If the power-up-reset-circuit is disabled at power up, the TAS5630 goes into READY-state at every power on.
At two failing boards we have changed the TAS5630 to the TAS5630B, this makes the problem disappear.
At the previous prototype series based at the same layout, we did not observe this problem.
What can cause this problem?
Thanks
Simon
