CD74HC04: Why hysteresis was added with the Die Revision change

Conor

Mastermind 9320 points

Part Number: CD74HC04
Other Parts Discussed in Thread: CD74AC04, CD74HCU04

Hi,

I previously made the following inquiry. I'm posting from a related question due to its "solved" status.

Q1.
Do you know why hysteresis was added with the Die Revision change?

Q2.
Even though hysteresis has been added, why is the PCN Electrical Specification item unchecked?

Thanks,

over 1 year ago

+1 Albert Xu1 over 1 year ago

TI__Mastermind 24025 points

Hi,

1. I can't give you an exact reason why this was a change made.

2. The electrical specifications have not been violated still, as answered in your previous questions. In this thread: https://e2e.ti.com/support/logic-group/logic/f/logic-forum/1190035/cd74hc04-there-is-hysteresis-in-the-chip-of-a-specific-lot Emrys goes more in depth about it and recommends CD74AC04 as an option without hysteresis.

0 Conor over 1 year ago in reply to Albert Xu1

Mastermind 9320 points

Hi, Albert

Is it correct to assume that there is no possibility that the design change of the CD74AC04 will somehow add a hysteresis function to the CD74AC04?

Thanks,

Eevee

0 Clemens Ladisch over 1 year ago in reply to Conor

Guru 271920 points

AC devices are sold in much smaller numbers than HC devices; it is unlikely that TI will change the design to improve efficiency. But it might be possible that such a change becomes necessary (or that the AC device is discontinued) if the old manufacturing plant is closed; there is no guarantee.

If you really need to rely on the analog characteristics of the input near the switching threshold, use an unbuffered device, i.e., CD74HCU04 or a *U04 device in another logic family.

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CD74HC04: Why hysteresis was added with the Die Revision change