TPS54218: Power supply load issue

jom sabu

Part Number: TPS54218

We are using TPS54218RTER in our board as 3.3V regulator, but some regulators output is not stable, it's output peak voltage is up to 3.6V and it's going down to 2v when load 200mA, this voltage is going down as per the load. The same setup worked when we replaced it with a new regulator TPS54218RTER . Schematics and Waveform are attached, Can you please verify the same?

over 4 years ago

0 Excel Regidor over 4 years ago

TI__Mastermind 30706 points

Hello Jom,

Can you share the layout as well while I'm checking the schematic diagram?

Thank you.

Best regards,

Excel

0 jom sabu over 4 years ago in reply to Excel Regidor

Intellectual 370 points

Hi Excel,

Please find the Layout file,

Regards

Jom

BRD_29SEP2020_REVP1_Ti.zip

0 Excel Regidor over 4 years ago in reply to jom sabu

TI__Mastermind 30706 points

Hi Jom,

Thanks for sharing the data. I will look at it and provide you feedback on Monday.

Best regards,

Excel

0 Excel Regidor over 3 years ago in reply to Excel Regidor

TI__Mastermind 30706 points

Hi Jom,

I will provide my feedback on Friday because I'm currently tied up with urgent case.

Thank you.

Best regards,

Excel

0 jom sabu over 3 years ago in reply to Excel Regidor

Intellectual 370 points

Hi Excel,

Did you check on this query? we are facing same issue in customer board, the situation is very critical. Could you please update this?

Regards

Jom

0 Excel Regidor over 3 years ago in reply to jom sabu

TI__Mastermind 30706 points

Hello Jom,

Apology for the late reply.

I compared the PCB layouts of the EVM and the customer boards, and the main difference only was the GND trace between the connection of the output capacitor. See the figure below for details.

I still need to discuss internally if other items might cause a high voltage spike during the decrease in load current.
Keep you posted for any update.

Customer board:

EVM layout:

Best regards,

Excel

0 Excel Regidor over 3 years ago in reply to Excel Regidor

TI__Mastermind 30706 points

Hello Jom,

Apology for the delay response.

The output voltage is set at 3.3V. Is it correct that input voltage (Vin) is also 3.3V (based on the schematic)? And to better understand the issue, please request below items to customer because it looks like the device operates in 100% duty cycle.

1. Same waveform as below but include the VIN and SW pin waveforms. Measure the switching frequency of the SW pin as well.

2. P/N of L28

Best regards,

Excel

0 Excel Regidor over 3 years ago in reply to Excel Regidor

TI__Mastermind 30706 points

Hello Jom,

Just a soft reminder.

Please ask customer to provide a waveform which includes VIN, SW, VOUT and IOUT.

Best regards,

Excel

0 Excel Regidor over 3 years ago in reply to Excel Regidor

TI__Mastermind 30706 points

Hello Jom,

Any update from the customer?

Thank you.

Best regards,

Excel

0 jom sabu over 3 years ago in reply to Excel Regidor

Intellectual 370 points

Hi Excel,

FYI

Input voltage of the regulator is 5V.
output voltage is set at 3.3V.
Load current is max 1A.

The issue is solved when we replaced it with a new regulator TPS54218RTER.

Is there any chance of failure with input voltage spike or compensation circuit design ?.

Regards

Jom

0 Excel Regidor over 3 years ago in reply to jom sabu

TI__Mastermind 30706 points

Hello Jom,

It looks like the device is already damaged, and the input voltage (VIN) likely went above the absolute max rating of the device. You can suggest to the customer to send the failed part for FA.

By the way, if there is an issue with the compensation circuit replacing it with a new sample will not resolve the issue.

Best regards,

Excel

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TPS54218: Power supply load issue