HI,
I am dealing with a startup problem on a prototype board and am looking for some clarification.
The circuit set up is as below with
R1 = 0 ohm
R2= not populated
C1 = 3.3 nF
The problem is that by the time the UCD part is powered up and driving the EN/SS pin low with the GPIO (using an open drain output), the EN/SS pin has gone high and has its outputs enabled already. When the GPIO becomes active it shuts down the already active TPS part creating problems downstream
If we populate
R1 = 1 kohm
R2 = 4.7 kohm
C1 = 1 uF
we would get similar RC response as the presently used 10 uA / 3.3nF config but would it create problems for the TPS calibration stage where the EN/SS pins get pulled/driven? to 1.3V
Other options?
thanks much
Bruce
