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

over 1 year ago

+1 Clemens Ladisch over 1 year ago

Guru 321790 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 V_IL is near GND, and that V_IH is near V_DD.

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

0 Tsuyoshi Nogi over 1 year ago 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 Clemens Ladisch over 1 year ago in reply to Tsuyoshi Nogi

Guru 321790 points

I do not assume anything about the typical values. Normally, the switching threshold is near V_DD / 2, and for other CMOS families, the V_IL/V_IH limits that ensure that there are no shoot-through currents are 0.3 × V_DD and 0.7 × V_DD. 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 × V_DD and 0.95 × V_DD.

0 Tsuyoshi Nogi over 1 year ago 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

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