CD74HC4538-Q1: Time it Takes to Power ON the Device After Internal Reset

TI-CSC

Genius 12905 points

Part Number: CD74HC4538-Q1

Hello E2E Experts.

Good day.

The part has an internal reset circuit. I'm referring to a normal power-on reset, with no faults.

I'm using +5V to power the IC.

My question: If 5V is applied to pin 16 and rises too slowly, this internal circuit

will stop working. How slow is too slow?

Will it reset properly if Vcc goes from 0V to +5V in 100 ns?

In 10 us?

in 500 us?

in 100 ms?

in 1 second?

What is this minimum rise time for Vcc, for which this internal reset still works?

Regards,

CSC

0 Albert Xu1 over 2 years ago

Hi,

Please refer to the transition rate in the datasheet shown below:

0 TI-CSC over 2 years ago in reply to Albert Xu1

Hello Albert,

Good day.

I understand. However, my question is about the VCC itself when the internal reset function happens. Not on the Reset and Trigger Inputs.

Is there any characterizations for this?

Regards,

CSC

0 Albert Xu1 over 2 years ago in reply to TI-CSC

Hi,

That's my bad I misunderstood at first. VCC transition rate isn't generally characterized.

Inputs are characterized as these signals can cause an unknown state which can lead to high currents.

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