Hi Team,
My customer find out a strange phenomenon with TPS2421-2: the device may latched-off permanently if the output is shorted to GND and released. During this latched off condition the CT pin is consistantly kept at 0V, no any waveform on it. This latched off condition cannot be released until the input power supply is cycled or /EN pin is cycled high and low again. This behavior seems as if it was TPS2421-1 instead of -2.
The circuit is same as typical ckt in datasheet: /EN is grounded permanently through 10k resistor, ISET resistor is 56k 1%, CT=0.47u.
The condition of each pin during latched off is:
PIN1: LOW
PIN2: LOW
PIN3: 5.19V
PIN4: 0V
PIN5: 0.979V
PIN6: 0.002V
PIN7: 0.054V
PIN8: HIGH
Is this condition correct for TPS2421-2? What is the possible root cause?
Thank you,
John
