LM393: Problem of abnormal output of LM393

Tool/software:

AB/BA interchange has been done. This time, 100% of the newly purchased batches are abnormal. The outputs of the old batches and the ON brand's LM393 are normal.

Application Circuit: Build a comparator circuit as shown in the following figure using LM393 to achieve overcurrent protection. Set a 6V reference voltage at the inverting input terminal, and connect the current detection at the non-inverting input terminal. The output terminal is pulled up to a 12V power supply through a 1k resistor, and a diode 1N4148 is used to feed the output voltage back to the non-inverting terminal to realize the overcurrent protection lockout function.

1. Using the original materials, the circuit functions normally: After the auxiliary power supply of 12V is powered on, the output of the comparator is at a low level. When an overcurrent occurs in the circuit, the output of the comparator changes to a high level.
2. Using the current materials, the circuit functions abnormally: After the auxiliary power supply of 12V is powered on, the comparator outputs a high level immediately. At this time, there is no current in the circuit, and the current detection signal is 0.     

Raw material model and test waveform:

Note: Channel 4 is the output; Channel 3 is the inverting terminal; Channel 2 is the non-inverting terminal

Current material model and test waveform:

Note: Channel 4 is the output; Channel 3 is the inverting terminal; Channel 2 is the non-inverting terminal