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TL16C550C: Auto Flow Control doesn't work in DIP-40 package

Part Number: TL16C550C

I am seeing the same problem as Andres Ortiz2 in this thread https://e2e.ti.com/support/interface-group/interface/f/interface-forum/930312/tl16c550c-auto-flow-control-doesn-t-work.

Specifically, the AFE bit cannot be set and always reads back as 0.  In the thread referenced, it is indicated that this problem could not be replicated, but it was not clear which package of TL16C550C was used:  DIP-40 or PLCC.  This problem only exists in the DIP-40 package in my testing.  I have tried many DIP-40 packages and they all misbehave as described by Andres.

Can you let me know if the testing that was done was on a DIP-40 package?

Thanks,

Wayne

  • Hi Wayne,

    I've assigned a UART expert to this thread. We will get back to you after the US holiday. 

    Regards,
    Eric Schott

  • Hi Wayne,

    The testing was done using the PLCC package of the device. The DIP package of the device is obsolete so we actually can't get a hold of it anymore. 

    I did do a look through on our system and found that the PLCC package and the DIP package have the same die so in theory both should behave the same way. The only differences would be thermal impedance numbers and very minor capacitance/inductance differences where the DIP package would have slightly higher cap and inductance. 

    Were you seeing issues related to temperature testing? (If so then maybe it is possible the DIP package has some kind of issue where the PLCC wouldn't see it). Otherwise I would guess that the discrepancy would be related to a system level where more capacitance/less capacitance on a certain pin could generate an issue in one device package but not the other.

    EDIT: Just thought of this, but this could also be related to silicon aging since the DIP package was canceled so many years ago.

    -Bobby

  • Thank you for the response.

    I don't think my symptoms are thermal or capacitance/inductance variation.  Literally, the AFE bit will not set -- always reads back as zero.  This is the case on many DIP-40 chips I tested.  Problem never occurs on PLCC variants.  Perhaps silicon aging.  I guess it is also possible that there are a bunch of counterfeit or remarked chips out there.

    Anyway, since the DIP-40 is obsolete, I think we are done.  I appreciate your time and effort.

    Thanks,

    Wayne