Test the quality of IC can be like this, first look at the IC pin data, prepare a normal IC, use the meter to test its PN junction, that is, adjust the table to the file with the diode words (the pen short will ring), test each pin to GND and normal IC what is the difference.
If there is an oscilloscope and a voltage regulator power supply is best, the VCC on the chip is connected to the voltage regulator power supply, the oscilloscope is connected to the mosfet driver foot, the voltage regulator source is slowly increased from 0v to about 15v to see if the oscilloscope displays PWM waveform, if there is normal