Customer is using the SN74LV123A to drive the LED of an optocoupler with 100 ohm resistor in series.
The SPICE simulation shows that the output drops (1Q) to ~1.5V with 2.7 mA being drawn, Vdd is 3.3V and ~ 1.4V dropped by the LED. This appears to make sense 1.4V + 100*2.7mA is ~ 1.7V which leaves 3.3V-1.7V at the output of the SN74LV123A (1Q).
There is no information in the datasheet mentioning the output voltage versus current.
- Is the simulation model correct? Will the output voltage drop to 1.5 V if the device output is loaded in the described manner?
- Is it ok to draw this that much current from the part? Will the part be damage in the long run.