Hello
My customer is using CD74HCT4051 for their new design FY2018.
However, there are problem ( oscillation at COM output ) for their ES borad in case by case.(cause unknown),
but customer is concerned about their power up sequence S0~S2, Enable and Vcc,Vee.
I had attached the schematic and also their problem as ppt file.
Q1 Criteria
Do you have criteria ( timing ) about relationship
between control input S0~S2 , /Enable and Vcc, VEE in case Power Up( and Down )?
We can not find the criteria those in data sheet.
Q2 Need help as Your opinion
In customer’s desig n, Enable ( and S0~S2) start up before VEE goes t- -4.5V.
Do you think this is problem?
Q3 Need help as Your opinion
In customer’s set, VEE goes +1V at a moment.( cause unknown)
Do you think this is problem?
With my Best Regards