SN74LVC1G79: Power-on reset state

David Hall

Part Number: SN74LVC1G79
Other Parts Discussed in Thread: SN74HCS74

Does this part (likewise, the "LVC1G80, 'LVC2G79 and 'LVC2G80) have any type of internal power-on reset that guarantees the start-up state of the Q (or /Q) output? Or do they just come up in a random output state at power up and have to have data clocked in to set the output to a known state?

over 3 years ago

0 Emrys Maier over 3 years ago

TI__Guru* 96681 points

Hi David, and welcome to the forums!

There is no internal power-on reset circuit - the output always starts in an unknown state.

This is an FAQ, located here: [FAQ] What is the default output of a latched device? (Flip-Flop, latch, register)

If you'd like to set the default state of a D-type flip-flop, the best solution is the SN74HCS74 (or '72) that allows for an RC circuit to directly control the PRE\ or CLR\ input pins due to Schmitt-trigger inputs.

Please let me know if I can be of any further assistance.

Logic

Logic forum

SN74LVC1G79: Power-on reset state