Hi,
Currently we are an issue with 74HC573 chip, the output lines going high for ~4.2s during power cycle. There is no change in the hardware, the circuit is working in the field for more than 6 years. This is issue is raised in recent PCBA batches.
Below is the circuit snap and details about the circuit.
This is the application circuit, the input signals are coming from a CPU and are pulled high to 5V by default. here the issue is, in working boards, the output signals for ex-signal FRD_BZR will stay low until there is some data from CPU. But in not working working boards, this signal going high for a short duration ~4.2s during power cycle time and after the 4.2s the circuit works normally as per the application. This is a quality issue reported.
Could you help on this how to sort out the issue. I have probed the input pin.7/output pin.14 and the latch enable signals for both working and not working board. Both input and latch enable is same for both the boards except the output signal pin.14 going high for short duration in not working board.
Waveforms for the issue and no issue boards are attached.
Waveform of the issue board, were the output signal (green) going high for short duration.
Wave of the working board, In this the output (green) is low during power cycle.
