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CD4043B: ENABLE pin H/L threshold with Vdd=3.3

Tsuyoshi Nogi
Intellectual 1970 points
Part Number: CD4043B
Other Parts Discussed in Thread: SN74AUP2G02, SN74AHC02

Tool/software:

Hi experts,

I would like to ask you about CD4043B.

I saw there are data at VDD=5,10,15V on datasheet.

but would you share the threshold of ENABLE high/low at Vdd=3.3V?

Thanks and regards,,

Tsuyoshi

  • +1
    Guru 311000 points

    CD4000 devices are optimized for higher voltages. There are no guaranteed characteristics at 3.3 V.

    You have to assume that there is almost no noise margin, i.e., that VIL is near GND, and that VIH is near VDD.

    There is no other integrated NOR latch device, but you can use plain NOR gates to implement a latch (e.g., SN74AHC02, SN74AUP2G02).

  • 0 in reply to Clemens Ladisch
    TI__Intellectual 1970 points

    Hi,

    So I could assume that typical threshold of L/H are almost 0/3.3 at room temperature but not guaranteed.

    Is my understanding right?

    Thanks and regards,

    Tsuyoshi

  • 0 in reply to Tsuyoshi Nogi
    Guru 311000 points

    I do not assume anything about the typical values. Normally, the switching threshold is near VDD / 2, and for other CMOS families, the VIL/VIH limits that ensure that there are no shoot-through currents are 0.3 × VDD and 0.7 × VDD. But for CD4000 at 3.3 V, the characteristics are so bad that the values are likely to be worse (but I don't know); the only safe value is something like 0.05 × VDD and 0.95 × VDD.

  • 0 in reply to Clemens Ladisch
    TI__Intellectual 1970 points

    Thank you for your comments!

    I understood that there isn't any material about characteristics with Vdd=3.3V.

    Thanks,

    Tsuyoshi