SN74HC165: Schematic check

Hi Clemens,

Now we have a big problem, that is, we use ACO CHN products have a large proportion of defective rate (input number of 890pcs, the number of defective number of 320PCS, the defective rate is up to 35.9%), while the previous use of ACO MYS are normal.

The label of ACO CHN and MYS is as below:

We are testing the complementary serial output pin (pin9) waveform and found that we have a big difference. The detalis are show as below:

We have taken photos under of X-Ray machine to check the difference of the wafer, and the result is as below:

We also noticed that the received product have both version of version A and E from agent , and Version E was goes well on our production , but Version A was still got pending due to failed the function testing at waveform test station , could you please let me know what different on both versions of IC  ?  and why are they taken both difference waveforms showing after we crossed both version ICs on the same PCBA  ? and the failure PCBAs have turn off the fail to pass after we removed the Version A ICs from PCBA , and use Version E ICs to replacement ?

Thanks,

Kind Regards

Please show an oscilloscope trace of the SWITCH_CLK signal.

Hi Clemens,

The waveform of the SWITCH_CLK signal is shown as below:

Thanks,

Kind Regards

Hi Clemens,

The left waveform of the SWITCH_CLK signal is the reference waveforms provided by the end customers, and the right side is the actual waveform measured by us.

Thanks,

Kind Regards

Where does this reference come from? Did the reference circuit not have C17/C18?

Anyway, I've already told you how to fix this: make the edges faster, or use the HCS device.