TPS61288: Device is getting damaged, intermediately

Part Number: TPS61288

Tool/software:

Hi

I am using TPS61288RQQR with the following specifications

Vin : 2.7V to 3.6V (from an battery)

Vout : 5V

Iout : 2A (Max)

It is observed that, In few builds, boost IC is not functioning and In few are getting failed intermediately.
When I checked the resistance on the Pin 4 and Pin 5, its more than 1kohm and in diode mode vf ~0.4V , intermediately IC starts heats up and when we power off and verify the resistance of Pin 4 and Pin 5 it goes in order of ohms and vf -0V 

Attaching schmeatics for ur reference 

Intially,Suspected the CAP on enable pin C297 is causing the issue, with that removal doesnot solve the issue yet. 

Do let me know the what is the possible issues and way forward for the same.

TIA

Regards
Chaitanya

  • Hi Chaitanya,

    From the schematic, the comp parameters could be improved, R69 C43 are suggested to set 10kohm + 5nF. I don't know if this causes the failure, but can have a try with new parameters. Please also refer to 9.2.2.8 Loop Stability for comp parameters design.

    Also usually think the failure are more likely related to the layout, could you share the layout for checking? Please refer to the layout guideline in datasheet also.

    Regards,

    Nathan

  • Hi Nathan

    Attaching layout for your reference.

    TOP LAYER

    BOTTOM LAYER

    Here are few observations,I have 
    Duirng no load conditons (when I isolate the output with the connected loads), device is not planning and working fine

    When I have connected an external load, when load current goes to 0.4A, device start failing.

    Regards

    Chaitanya 

  • Hi Chaitanya,

    The layout looks also no big risk as I see, can you try to capture the fail waveforms to share? Like the input voltage, vout voltage, SW voltage, load current for example?

    Regards,

    Nathan