Hi, I have a SN74LVC1G125 which I'm using as basically an open-collector driver. The data pin is tied to GND, and other logic is driving the OE_N pin. The power supply is 3.3V. I have 10k to the same 3.3V pulling up the OE_N pin.
When my part of this system powers up, the output is already pulled up to ~3.3V (another power supply). When the LVC logic supply is between about 0.5 to 1.2V, the output drives 0. As it continues up to 3.3V, it goes back to high impedance. I checked the OE_N pin, and it is nicely tracking the power supply, which implies that the upstream logic is not turning it on.
The data sheet says (p.1), "To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver." OK, so I guess that implies it should be possible to have this be high-impedance during power up, but I'm not sure exactly how to make this happen. The next thing upstream is another LVC logic part, which at first glance is behaving exactly how I want it to on power up.
The behavior has been confirmed on 2 boards.
