TINA/Spice/UA741: power-up sequence of the dual-supplied opamp

Hi,

you might want to have a look at this thread:

The OPAmp isn't actually seeing the positive and negative supply voltages, but only the voltage difference between the supply terminals. So, as long as the input voltages and output voltage of OPAmp are always (at any point of time!) within the allowed range (see the absolute maximum ratings), there should not be any damage.

Sometimes an oscillation can be seen at the output when the supply voltage slowly goes-up or -down and moves through the minimum supply voltage needed for stable operation. Increasing the supply voltage decoupling capacitances by adding electrolytics can considerably minimize this effect.

I have never heard that a 741 was destroyed because of a too slow power-up. Nevertheless, it's always wise to provide a fast power-up with a steady rise of supply voltage for any electronic circuit. On the other hand, think about how many zillions of 741 are arround that are powered by a standard "mains transformer + rectitifier + linear voltage regulator" combination which can have a power-up time of several mains voltage half cycles and a power-down time of some seconds. And all are working properly since decades...

Kai

Hello User,

During power up and power down when supply voltage or input common mode is outside recommended range, the output may go low, high, or something else. The op amp doesn't care about supply order or rise time , but the application circuit might care about the uA741 output during power up / down.