TPS629210EVM: TPS629210EVM

Evangelos Almpanidis

Part Number: TPS629210EVM
Other Parts Discussed in Thread: TPS629210

Hello!
I am trying to get the TPS629210 on TPS629210 evaluation module to output 3.45V .
I have used the formula indicated to the datasheet (page20), and Replaced R2 with 32.4K .
The configuration Jumpers are to the default position.
The problem is that I am only getting 2.5V as output.
I have tried this with two different kits and the result is the same.
According to the datasheet it should be possible to get 3.45V.
Is there any other component that needs to be changed?
Is it possible that the default configuration of the kit is not valid for 3.45V operation?

over 2 years ago

0 Joseph Conrad over 2 years ago

TI__Expert 7860 points

Hi Evangelos,

What is your input voltage set at?

The device supports Vout betwen 0.4V - 5.5V so you should be able to achieve 3.45V.

Your resistor divider modification is correct for getting 3.45V.

Thanks,

Joseph

0 Evangelos Almpanidis over 2 years ago in reply to Joseph Conrad

Prodigy 40 points

Hi Joseph!
Thanks for the reply!
The input voltage is 5V.
I have tried to simulate with Pspise for TI and the output is indeed 3.45V.
My concern is that the issue happens to two kits. I have checked the board again and everything looks fine. The only thing I have change is R2 (I used a 0402 32.4K though, but I don't think this is the case). The simulation also includes a 2.2uH inductor instead of the 3.3uH on the dev kit.
Can this be the issue?

0 Joseph Conrad over 2 years ago in reply to Evangelos Almpanidis

TI__Expert 7860 points

Hi Evangelos,

The 3.3uH inductor on the EVM should work just fine for 3.45V output.

I would double check that the resistor is soldered down correctly. Since it is 0402 it may be a little short missing the pads since it is designed for 0603.

It would also be a good idea to double check the FB pin and VOUT waveforms to see if the device is regulating correctly. The FB pin should be regulating to 0.6V.

Thanks,

Joseph

0 Nancy Zhang over 2 years ago in reply to Joseph Conrad

TI__Mastermind 47580 points

Hi Evangelos,

Changing R2 to 32.4k is correct. The EVM can be configured to 3.45V. Please check below things.

1. Use alcohol pad to deep clean the feedback R1/R2 area after you replaced R2. As Joseph said you may use 0603 package resistor to instead of 0402.

2. Make sure the R2 resistor you replaced is 32.4k

3. Make sure the JP2 jumper setting is on the FPWM or APFM on the left side

4. Try no load first.

Hope these help,

Thanks,

Nancy

0 Evangelos Almpanidis over 2 years ago in reply to Nancy Zhang

Prodigy 40 points

Thanks Nancy and Joseph.
The resistor is indeed 32.4K .
The jumper for external FB(JP2) is configured for APFM (I have also tried the FPWM but the issue persist).
I am testing without load.
I 'll replace the resistor with a 0603 one and see if this solves the issue.
Many thanks
Evan

+1 Nancy Zhang over 2 years ago in reply to Evangelos Almpanidis

TI__Mastermind 47580 points

Hi Evan,

Please clean up the board after you replacing the resistor since the flux residual may cause output voltage inaccuracy. Usually we drop the board to the ultra sound cleaner to 10 min to deep clean the board after soldering. At least you need to use alcohol or water to brush the feedback area.

Thanks,

Nancy

0 Evangelos Almpanidis over 2 years ago in reply to Nancy Zhang

Prodigy 40 points

Thanks for the tip Nancy!
I 'll do as you suggest and let you know if this helps!

0 Evangelos Almpanidis over 2 years ago in reply to Nancy Zhang

Prodigy 40 points

Hi Nancy!
This was the issue.
I cleaned the area with alcohol and it is OK now.
Thanks for your support.
Evan

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TPS629210EVM: TPS629210EVM