SN74LVC541A-EP: Y1 output level during Vcc ramp up

Hello,

My customer plans to use SN74HC14-EP and SN74LVC541A-EP as follows.

Both SN74AHC15-EP input and SN74LVC541A-EP A1 stays low.

Vcc of SN74HC14-EP and SN74LVC541A-EP linearly and slowly ramps up, it takes 2 minutes to get 3.3V from 0V.

In this case, SN74LVC541A-EP Y1 stays low, or could be high somehow during Vcc ramp?

Best regards,

K.Hirano

The '14 inverter does not have an OE pin, so its output can switch randomly while the supply voltage is still below 2 V. Therefore, it is possible that the '541 outputs get enabled at that time.

To ensure that the OE pins stay high while V_CC is ramping up, connect them to V_CC with a weak pullup, and force the inverter to power up later (e.g., power it from a GPIO, if one is available).