Hi Team,
Customer uses ULN2003A found a wrong result:
Normally, Pin1 is 3.3V, then Pin2 is 0.6V, and Pin15 is a high voltage;
But one of the channels will happens, Pin1 is 3.3V, then Pin2 is 0.6V, and Pin15 is also 0.6V.
Schematic is shown below, could you please help check whether there is any mistake with circuit? Or is there something I am missed? Thanks a lot.
BRs,
Francis
Hi Elizabeth,
I see the whole schematic, it is simple just as below figure, and the input is from MCU I/O, output is disconnected.
Are these pull up resistors and source are suitable? Will sink current exceed the threshold of device?
BRs,
Francis
Hi Elizabeth,
Thanks for your great help. Actually, I failed to recurrent the abnormal waveform, I confirmed COM is tied hard. Seems system design problem.
No problem here, thanks a lot! 
Have a good day!
BRs,
Francis
Hi Francis,
This device is meant to connect/disconnect loads from ground. The "pull-up resistor" would be your load which the device connects and disconnects from ground. The device can handle 50V VCC and the load capability is 500mA max when using only one channel.
The following plot shows the max collector current as a function of duty cycle and number of channels conducting simultaneously.
Best Regards,
Elizabeth
