TPS54538: Issue with TPS54538RQFR

Sandeep Maurya

Prodigy 20 points

Part Number: TPS54538

Tool/software:

Dear TI Support Team,

We are facing an issue with the TPS54538RQFR in our design.

Input Voltage: 24V / 3A
Configured Output: 5V
Circuit: Followed reference design from the datasheet for 5V output.

After a few power cycles (on/off), we observed that the buck IC failed and subsequently damaged all peripherals connected to its output.

Upon debugging, we found a short on both the input and output sides, which was cleared only after removing the buck IC. It appears that during failure, the IC may have passed the full input voltage to the output, causing damage to the downstream components.

Could you please review and advise if we might be missing anything or if there are known failure conditions under these operating parameters?

Looking forward to your guidance.

Please refer the attached schematic

Best regards,
Sandeep

3 months ago

0 Gautam Iyer 3 months ago

TI__Genius 10470 points

Hi Sandeep,

Is R6 10E? Why is this required/placed?

Regards,

Gautam

0 Sandeep Maurya 3 months ago in reply to Gautam Iyer

Prodigy 20 points

Yes, R6 is 10E,

Used this to limit the surge current,

I have tested after removing the R6 as well and observed same issue,

0 Haseen Reddy Siripi Reddy 3 months ago in reply to Sandeep Maurya

TI__Expert 5530 points

Hi Sandeep,

Please share the waveforms of VIN, VSW, Vout.

Regards,

Haseen.

0 Suraj J R 3 months ago in reply to Haseen Reddy Siripi Reddy

Prodigy 20 points

Hi Haseen Reddy Siripi Reddy

I am Suraj JR, an hardware engineer working with Mr. Sandeep. PFA the waveforms as requested.

Test Setup:

Input voltage: 24V

Input current limited to 2.5A

Output voltage : 5V

Max. output current the board is designed to handle: 5A

Actual load draws 3A at the output. The load was made by connecting 12 nos. of 22ohm 5W power resistors in parallel

V_SW & VOUT

This is V_SW & VOUT.

VOUT & VIN turn on from 3A load

This is VIN & VOUT with a 3A resistive load during turn ON of the power supply

VOUT & VIN turn off from 3A load

This is VIN & VOUT with a 3A resistive load during turn OFF of the power supply.

Peculiar issue to notice is that we have hand soldered 5 boards and only 2 work. Rest all worked intermittently but got shorted as soon as we turn on the input which full load already connected at the output or we perform repeated power cycling of the board.