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SN74HCS237: doubts on datasheet SN74HCS237

Matteo Tarquini1
Prodigy 75 points
Part Number: SN74HCS237
Other Parts Discussed in Thread: SN74LVC1G373

Hello,

probably there is a mistake in SN74HCS237's datasheet.

In pag.1 under Description  "When the latch enable (LE) input is high, the device acts as a standard three to eight decoder. When the latch enable (LE) input is low, the address latch retains its previous state."

but on page 11 the table 8-1. Function Table says an opposite functional mode. 

Which one is correct? 

Regards,

Matt

  • 0
    TI__Guru* 97046 points

    Hi Matt,

    Thanks for letting us know about this issue.  The 'HCS237 has the same functionality as all of our '237 logic devices.

    The front page description (pg 1), as well as the Detailed Description Overview (pg 9) will be changed to read:

    When the latch enable (LE) input is low, the device acts as a standard three to eight decoder. When the latch enable (LE) input is high, the address latch retains its previous state.

  • 0
    Prodigy 75 points

    Hi Emrys,

    Thank you for the quick answer. This resolved my issue.

    Best regards,

    Matt

  • 0 in reply to Matteo Tarquini1
    TI__Guru* 97046 points

    Hey Matt,

    I just wanted to let you know that we have completed the changes to the SN74HCS237 datasheet.

    In addition to fixing the wording in the description, we also went through and updated the LE to be LE throughout the datasheet to make it more consistent with the remainder of our portfolio (parts like SN54LS237 and SN74LVC1G373). This also led to a minor revision of the functional block diagram.

    This all stemmed from the definition of Latch Enable being a bit confusing.  To be clear (for anyone who finds this in the future also), the definition we are using for "Latch Enable" is:

    A D-type latch is enabled when it allows data to pass through it, and a D-type latch is disabled when it holds the output state.