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TPS43060: Device failure when toggling EN in a circuit heated to 50 °C

user5874164
Prodigy 90 points
Part Number: TPS43060

Hi, 

I have a 12V to 32V booster circuit using tps43060. 

In normal conditions this circuit works fine, but I have a issue when the PCB is heated to approximately 50 °C. 

When the circuit is heated, I then turn the device on and off a few times using the EN pin witch is connected to a MCU. 

This makes the tps43060 do one of two things:

1: Gets very hot (100°C+), but still functions normaly.

2: Output voltage drops bellow 32V and I see a loot of rippel, and PGOOD is pulled low.

This behavior continues after the circuit is cooled down and restarted. 

Switching out the broken tps43060  with a new tps43060  fixes the problem and the circuit operates normaly until it is heated again. 

 

  • 0
    TI__Guru* 78060 points
    Hi user,

    Did you have the underpad of the TPS43060 soldered, and that is connect to the ground plane for heatsink? I am afraid you have the thermal issue and your PCB may not dissipate the heat well from the IC. Please refer to the EVM PCB layout to see the underpad land pattern.

    Thanks,
    Youhao Xi, Applications Engineering
  • 0 in reply to Youhao Xi
    Prodigy 90 points

    The underpad is soldered and connected with 4 vias to groundplane on the other side of the PCB. 

    I have now also discovered that it seams like the is something else in my circuit need to brake before the  TPS43060 starts failing. I tried with a fresh pcb, heated it, and it did not fail. Then, after a while  suddenly TPS43060 fail when heated, and all replacement TPS43060 also fails when heated circuit. not sure of exactly what i did to the circuit that lead to this change in behavior. 

    Is there any known mistreatment that I may be doing to the TPS43060 that causes this type of brakedown? 

    Also, I see a short flash of heat generated in the TPS43060 when V_inn is connected on my IR camera. This both on working and broken units. Don't know if this is at all related. 

      

  • 0 in reply to user5874164
    Prodigy 90 points

    I have also discovered that there is only 20 ohm between SW and boot on the broken chips, on new chips i measure 6 Mohm.