SN74LVC574A: Power down lock down feature

Jeff Xie

Part Number: SN74LVC574A
Other Parts Discussed in Thread: MSP430FR2000

Hi team,

Customer want to use a trigger that can be used as a memory function, that is, it can remember the previous state after power-off.

Can SN74LVC574A do this job? If not, do we have part to do this? Thanks.

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 267920 points

All logic devices lose their state when powered off. (The SN74LVC572A datasheet says in the recommended operating conditions that data retention requires at least 1.5 V.)

You could add a backup power supply (battery or supercapacitor) for the flip-flop. Alternatively, use a microcontroller with non-volatile storage (the simplest one would be the MSP430FR2000), which needs programming.

0 Jeff Xie over 4 years ago in reply to Clemens Ladisch

TI__Intellectual 1780 points

Ladisch,

What is the initial status of SN74LVC572A when it is powered on. Is Q0 status set or unset?

Does customer need to reset it?

0 Clemens Ladisch over 4 years ago in reply to Jeff Xie

Guru 267920 points

It's unknown. See [FAQ] What is the default output of a latched device? (Flip-Flop, latch, register)

The only way to get into a known state is with the clock and data inputs.

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SN74LVC574A: Power down lock down feature