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SN75ALS176B: PCN details

Kazuki Itoh
Genius 9565 points
Part Number: SN75ALS176B
Other Parts Discussed in Thread: THVD1550

Hi team,

My customer would like to check the PCN# 20230112001.1 details.

1. It is mentioned that SN75ALS176B electrical specification has changed.
Could you let me know what electrical specification changed exactly?
Is it just only thermal information table?

2. From the thermal information table, it looks like the thermal resistance has changed from θJA 97℃/W to RθJA 110℃/W.
Has other thermal resistance like ΨJT changed?
Could you let me know the relevant thermal parameters before the PCN?

Best regards,
Kazuki Itoh

  • +1
    Guru 265760 points

    1. The previous device was built on a very old, bipolar process ("Advanced Low-power Schottky"). The new device is a CMOS device that has been designed to be within the datasheet limits; all the typical values have changed. (I suspect that it is not a completely new design, but that the die is the same as that of a modern transceiver like the THVD1550.)

    2. In the previous datasheet revision, θJA was the only thermal parameter. In any case, the new device has a much lower power consumption.

  • +1
    TI__Mastermind 46217 points

    Hi Itoh-san,

    1. All reported electrical changes are listed in PCN and in datasheet:

    Thermal and typical characteristics changed - but this is reported on the typical characteristics graphs and thermal table. The Typical characteristic graphs are not guaranteed values and should only be used for illustrative purposes to give an idea of how typical behavior could look - all designs need to be designed w.r.t. min/max conditions as listed in the electrical and timing specification tables. 

    The device is still bound by the same conditions for legacy and new material in terms of performance. So if the system was properly designed with legacy material it will work with new material (barring any exceptional edge cases - which are very rare but not impossible - but the changes were reported a year ago so its too late to fight back against any change) . It would be very helpful if they review PCNs as soon as possible because they are time sensitive

    2. The thermal characteristics table was added so largely it was undefined - we didn't really specify much at all  in terms of thermal parameters on old material and from an applications point of view it's pretty much worthless because most thermal parameters change dramatically from system to system which means they need to qualify it themselves to determine thermal performance in their system (they need "effective" thermal parameters which are the values when customer system is considered as well) . In general the thermal performance is marginally worse on new material - but we have yet to see a problem caused by this and they still need to do their own thermal analysis as what we have provided is "as is". 

    Best,

    Parker Dodson