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CD74HC4016: CD74HC4016PW lot differences

E P
Prodigy 10 points

Part Number: CD74HC4016

Hello, 

We have used CD74HC4016PW for many years and it has worked fine, lately we have seen that the switches are not switching to an as low of a voltage as they used to. The switching voltage at pins 13, 5 and 6 has not changed. 

We were able to track it down to lot numbers, for example parts with marking number D1J4 works and switches at the voltages that has always switched around 0.2V , but parts with marking numbers A37R do not switch at the typical voltage and require a much lower voltage to switch almost -0.1V. 

Have there been any changes between the 2 lots? We might still be able to use the newer lots but I am trying to figure out a root cause. 

Any help would be appreciated. 

Thank you 

  • 0
    TI__Intellectual 1450 points

    Hello,

    I'm having trouble understanding what you mean. Do you mean the required nE voltages to turn the switch off are 0.2 V and -0.1 V, for D1J4 and A37R marked muxes respectively? Or are you saying when the mux is switched on, that the output pins are at a different voltage than expected?

    Thank you,

    Aidan

  • 0 in reply to Aidan Singh
    Prodigy 10 points

    Aidan,

    Your first statement is correct the switching for the 2 lots happens at slightly different voltages. This is not violating anything with the stated voltages on the Datasheet but for our design it makes a difference. 

    Thank you 

    E

  • 0 in reply to E P
    TI__Intellectual 1450 points

    I see. I've looked up both lot numbers and both were made at the same fab with the same die, so I am unsure why there is a difference. I also find it odd that the new lot requires -0.1 V to turn off. Would you be able to send me a graph showing at exactly what voltage the switch turns off and on? This device should be turning off when nE is 0.5 V, 1.35 V, or 1.8 V depending on the VCC.