Issual of TPS62130

xiaohua zheng

Other Parts Discussed in Thread: TPS62130

Hi,

I've used TPS62130 in my board,

all these function (12V to 3.3V,12V to 1.8V,12V to 1.2V,12V to 1.5V,12V to 1.0V) were done by TPS62130RGTT,my circuits is like this:

Sometimes the 1.0V were out of work,others outputs are all functional.

The 1.0V power for FPGA(xilinx 7A100t,2A max was tested by a DC power),the onle difference between ours from your recommended parameters is the value for R1 and R2 resistors.

I found those values are (R1=51k,R2=200K),But I've used(R1=2.5K,R2=10K) for it,the figure signs R1=5.1K is wrong,that value is R1=2.5K.

Could that be an problem?

Many thanks

Tom

over 9 years ago

0 Bernard Keogh over 9 years ago

TI__Genius 9130 points

Xiaochua,

I think you have posted your question to the wrong forum - this is for AC-DC & DC-DC Isolated products.

I would suggest that you post instead to Non-isolated DC-DC forum here, where you are more likely to find an answer to your question:
e2e.ti.com/.../

Thanks,
Bernard

0 xiaohua zheng over 9 years ago in reply to Bernard Keogh

Prodigy 220 points

Bernard,

I don't know how to move this question to that place you told me,Could you please move it to there ?

Many thanks

Tom

0 Chris Glaser over 9 years ago

TI__Guru**** 150830 points

It seems the image you posted did come through. Can you try posting it again?

Can you explain what the failure is?

0 xiaohua zheng over 9 years ago in reply to Chris Glaser

Prodigy 220 points

Hi,
The circuit is just like your recommended in the datasheet,But R1=2.5K,and R2=10K,the output C=330uF.
The TPS62130 was damaged while power on board for a while,maybe one hour or longer.

0 JohnTucker over 9 years ago in reply to xiaohua zheng

TI__Guru**** 191445 points

330 uF may not work well with TPS62130. See table 2 in the datasheet for recommended output filter combinations.

0 Chris Glaser over 9 years ago in reply to JohnTucker

TI__Guru**** 150830 points

This should not be causing damage. How much additional Cout is downstream at the load?

What do you mean by 'damaged'? What is the failure and how are you detecting/measuring this?

0 xiaohua zheng over 9 years ago in reply to Chris Glaser

Prodigy 220 points

Hi,

The internal resistor between pin SW and GND is about 3ohm for the damaged TPS62130,And there is no square wave on pin SW when it's powered on;Then I replced it by a new TPS62130 and it's work good.I thought the TPS62130 was damaged according to these conditions.

The FPGA(xilinx 7A100T) required at least one 330uF capacitance,But 330uF is not recomended.I'm tring 33uF now.

could a 330uF(between VOUT and GND,closed to VOUT pin) capacitance cause TPS62130 damaged?by the way,I've tested the max current of 7A100T on 1.0V,the value is 2A.

Is there a range value for R1 and R2?The configuration of (R1=2.5k and R=10K,for 1.0V ouput required radio) is good?I see much larger value in your datasheet for 1.0V ouput,recommended value are R1=75K,R2=200K.

Tom

0 Chris Glaser over 9 years ago in reply to xiaohua zheng

TI__Guru**** 150830 points

That much Cout could be ok per this app note: www.ti.com/.../slva463a.pdf

It is impossible to say without seeing your schematic and the other values in the circuit.

The resistors are ok per this app note: www.ti.com/.../slyt469.pdf

Could you post your PCB layout? This is the most common cause of SW damage.

0 xiaohua zheng over 9 years ago in reply to Chris Glaser

Prodigy 220 points

Hi,

Please see the attachment.

0 xiaohua zheng over 9 years ago in reply to Chris Glaser

Prodigy 220 points

Hi,

0 Chris Glaser over 9 years ago in reply to xiaohua zheng

TI__Guru**** 150830 points

Thanks for posting.

Your layout looks basically ok. I recommend removing C21. This can couple noise into the VOS pin.

Could you share the part numbers used for L7, C19. and C20?

How much capacitance do you have after the ferrite beads?

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Issual of TPS62130