Hello,
I'm using the CD4025B NOR gate in a very simple circuit. The problem I have is that it doesn't power up at the correct voltage on Vdd. I use a voltage divider to reduce the supply voltage of around 24Vdc to around 5.3Vdc. The majority of my boards work. I will measure around 5.3Vdc on Vdd, but on the few that don't work the voltage at the Vdd pin seems to get stuck at 2.9V. When I replace the CD4025B with a new on it fixes the power up problem.
Could the problem be with the IC ? a few bad in a batch?
All the unused input pins are connected to 0V. The unused output pins are open.
We tested 17 boards and two had this problem. Then I tested 20 boards and 3 had this problem.
I can't figure out what's going on.
Also, sometimes if I touch with my finger any one of the 3 input pins to the one NOR gate I'm using the circuit starts to work. The Vdd pin goes to 5.3Vdc. But once power is removed and then turned back on the Vdd pin gets stuck at 2.9Vdc again.
Any comments or ideas on what's going on?