SN74HC373: ask the logic table of SN74HC373

Iven Xu

Intellectual 2090 points

Part Number: SN74HC373

Hi expert,

here I would like to confirm with product line about the logic function table of SN74HC373.

when OE is L, LE is L, what's the Q0?

does it deped on the previous D and Q0 = previous D?

Best Regards

Iven

over 6 years ago

0 Emrys Maier over 6 years ago

TI__Guru* 96591 points

Hello Iven,
Q0 refers to the previous state of Q. Note that the highlighted line indicates that the LE (Latch Enable) pin is LOW (ie disabled) so the output no longer follows the D input.

0 Iven Xu over 6 years ago in reply to Emrys Maier

TI__Intellectual 2090 points

Hi Maier,

So if customer changing from below condition #1(OE=H, LE=L -> Q=Z) to condition #2 (OE=L, LE=L), than the Q0 should be refered to the previous state of Q, which is Z, right?

Thanks and best Regards
Iven

0 Clemens Ladisch over 6 years ago in reply to Iven Xu

Guru 243980 points

No; the output enable is independent from the internal Q state. Q0 always refers to the value (high or low) that D had when LE was last active (or is undefined if LE was never active).

0 Iven Xu over 6 years ago in reply to Clemens Ladisch

TI__Intellectual 2090 points

Thanks I think it is clear after your explannation.

so if the LE was disabled when the system just be powered up, then the Q0 should be in undefined status even change the LE from L(disable) to H(enable).

thanks and best regards

Iven

0 Iven Xu over 6 years ago in reply to Iven Xu

TI__Intellectual 2090 points

Sorry for the typro...

We have verified in my board: if the OE was disabled (H) when the system just be powered up first time, then the Q0 should be in undefined status even change the OE from H(disable) to L(enable) and keep LE=L.

thanks and best regards

Iven

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SN74HC373: ask the logic table of SN74HC373