How could TPS54335ADDAR be damaged with PH pin shorting to GND ?
And in the datasheet, I can't get information about selecting switching frequency, do you have any recommendation about that ?
Or is there any other Pin-to-Pin chips suitable to take replace of TPS54335ADDAR for stable and safe application?
Three TPS54335ADDAR are applied on our product PCB. One is for 12V- to-8.8V, another one is for 12V-to-5V, the last one is for 12V-to-3.3V.
Now we found PH pin of TPS54335ADDAR has been shorted to GND on 15 pieces PCBs of total 2000 units. All the fail appearance are found after a period of use.
11 pieces of failed TPS54335ADDAR chips are the ones for 12V-to-8.8V and 4 pieces are the ones for 12V-to-5V.
Load current of 8.8V is tested about 480mA to power the backlight circuit of LCD.
Load current of 5V is tested about 300mA.
Load current of 3.3V is about 1.65A.
Switching frequency of the three application are selected 1.5MHz. The type of inductor is SPM6530T-4R7M with 6.2A rating current.
The output capacitors of 12V-to-5V are 47uF/6.3V, The output capacitors of 12V-to-8.8V are 47uF/16V.
