We are using an ISO7220 as a substitute part in an older design.
We have seen on some of our boards that when the device first powers up, the output does not reflect the input. Once the input is changed, the output then follows the input correctly.
Below is a scope shot showing the problem
CH3 = VCC1(+5V_FIBER)
CH4 = VCC2(+3V3)
CH2 = INB(OUTPUT U22)
CH5 = OUTB(PLUG_OK_A)
Here it shows that the input to INB is LOW however OUTB goes high and stays this way. Not shown in the scope shot is that once INB is transitioned, OUTB then follows correctly. Is this expected behavior? We have never seen this before with other parts.