Tool/software:
SN74HC74DR,Different batches of chips,they have different waveform.
Why is this?
Correct waveform
Abnormal waveform
Please show the schematic, and tell us which signals you have measured.
Sorry!We do not agree to send the schematic here.
This is the output waveform of the 5 and 6 pins tested.
Then at least also show the input waveforms.
Ensure that all inputs (also those of the second flip-flop) have a valid voltage.
1、The driving pulses of GH and GL for normal pulses are determined by the duty cycle. Actually, the GL is high level, and the GH adjusts the duty cycle.
2、The input voltage is 5V.
This device does not have pins named "GH" or "GL".
Please show the input and output waveforms.
What else is needed besides the input signal waveform? We can provide the past at once.
I need signal of input on data and clk and a signal of the output on Q at least. Signals of pre and clear would also be helpful since I do not have a schematic and have no way of determining how they might be connected.
This is the input and output waveform of the abnormal chip.
pin5--yellow; pin3--blue; pin6--purple.
These waveforms show that the outputs toggle at every rising edge of the CLK. This is what I would expect (when /Q is connected to D).
What exactly do you think is wrong with this waveform? How does it differ from the other chip?
The normal logic is shown in the diagram.
This is the output waveform of the abnormal chip.
pin5--purple, pin6--green
Please zoom in, and also show the clock signal.
What is the slope of the clock edges?
1、Do you need the slope of the clock edge of the abnormal chip or a normal chip?
2、The clock signal is shown in the following figure,pin3-blue.
1. The slope is the same in all circuits.
2. This waveform looks correct. What exactly do you think is wrong with it?
We retested the waveform.
1、The following figure is an input waveform diagram.
2、The following figure shows the waveform of abnormal output from pin 5.
3、The following figure shows the waveform of abnormal output from pin 6.
This is the input and output waveform of the abnormal chip.
input-yellow, pin5-purple, pin6-blue
The output toggles at every rising clock edge. This is correct.
So far, I have not seen any difference in the zoomed-in waveforms. If the problem vanishes when you zoom in, then this is just a measurement error.