Need help on schematics/layout verification based on TPS54560-Q1

Aravind .R

Other Parts Discussed in Thread: TPS54560-Q1

Dear ALL,

one of our customer is working on 48V-12V,5A power supply for automotive applications, we have suggested TPS54560-Q1 and they did a design based on same.

Attached schematics and layout for reference, kindly need help to verify the same and advise valuable feedback.

Rgds,

Aravind.

over 8 years ago

0 JohnTucker over 8 years ago

TI__Guru**** 191445 points

Please post the design requirements and the equations used to determine the component values. Otherwise I can only look for obvious errors and component values that are unusually large or small.

0 Aravind .R over 8 years ago in reply to JohnTucker

Genius 3175 points

Dear SIr,
Please find below the specs for customer did design

Input voltage: 48V-Battery voltage in vehicle
Output voltage: 12V
Output current: 5A

Aravind

0 JohnTucker over 8 years ago in reply to Aravind .R

TI__Guru**** 191445 points

Any input voltage range? Any other care abouts, such as load transient response? I still need the design equations, otherwise just a cursory review.

0 Aravind .R over 8 years ago in reply to JohnTucker

Genius 3175 points

Sir,
Minimum will be 48V, it may go upto 60V. As it is automotive application,load transient response is needed. Cursory review will be fine here.
Need your help on reviewing components values where it is abnormal and needs to be changed to certain value for better operation /proper o/p and also layout verification.

Aravind.

0 JohnTucker over 8 years ago in reply to JohnTucker

TI__Guru**** 191445 points

Do you have a pdf of the schematic? The bitmap image is too small and blurry to read.

0 Aravind .R over 8 years ago in reply to JohnTucker

Genius 3175 points

Dear Sir,

Please find attached schematics, please help to review and advise your feedback, thanks.

Rgds,

Aravind.4682.Sch.pdf

0 JohnTucker over 8 years ago in reply to Aravind .R

TI__Guru**** 191445 points

I don't see anything that jumps out at me as being wrong. With all that circuitry on the input, you may want to add a little bulk electrolytic capacitance after Q1 on the input.

0 JohnTucker over 8 years ago in reply to JohnTucker

TI__Guru**** 191445 points

Also the layout seems to have disappeared. Can you re-post it?

0 Aravind .R over 8 years ago in reply to JohnTucker

Genius 3175 points

Dear Sir,

Any suggestion on bulk electrolytic capacitance value that has to be added.

please find attached top solder layer and bottom solder layer for review sir.

Aravind.

0 JohnTucker over 8 years ago in reply to Aravind .R

TI__Guru**** 191445 points

You should consider moving the input bypass capacitors closer to the VIN pin with a direct top side connection to GND. Also your SW node copper fill is too large with L1 too far from the IC. the return paths for D2 and D3 are too long as well. for both the input and output circulating paths, these connections are best accomplished by connecting at the pin 1 / pin 8 side of the IC, so you will probably need to change the orientation of U1. See teh layout guideline in the datasheet and teh EVM layout in the users guide for ideas on how to re design your PCB.

0 Aravind .R over 8 years ago in reply to JohnTucker

Genius 3175 points

Dear Sir,

Please find attached layout, customer modified as per your recommendations. please help to review the same and advise.

Thanks,

Aravind.

0 JohnTucker over 8 years ago in reply to Aravind .R

TI__Guru**** 191445 points

Much better. I would place D2 and D3 directly in parallel by Mving D2 down and placing D3 above D2.

0 Aravind .R over 8 years ago in reply to JohnTucker

Genius 3175 points

Dear Sir,

Please find attached modified layout as per your recommendations, kindly check and advise for customer to proceed further to make PCB, thanks.

Aravind.

0 JohnTucker over 8 years ago in reply to Aravind .R

TI__Guru**** 191445 points

If you want the best possible layout, Move D2 and D3 farther down, closer to the IC adjacent to C1. You should them be able to move L1 to the right, shortening the SW node path.

0 Aravind .R over 8 years ago in reply to JohnTucker

Genius 3175 points

Dear Sir,

Greetings. Modified layout attached, please check and advise, thanks.

Rgds,

Aravind.

0 JohnTucker over 8 years ago in reply to Aravind .R

TI__Guru**** 191445 points

While that is different, I'm not sure it is actually any better than the previous layout. The idea is to minimize the distance between the anodes of D2 and D3 to the GND pins while also minimizing the SW node. The best way is to move D2 and D3 down so that D2 anode is adjacent to C1 , directly above U1. I think it is ok to have L1 above D3. Otherwise you will have to move everything to the left to fit L1 to the right of D2, D3.

0 Aravind .R over 8 years ago in reply to JohnTucker

Genius 3175 points

Dear Sir,
Plz advise whether customer can proceed in making PCB as per last layout attached.

Rgds,
Aravind

0 JohnTucker over 8 years ago in reply to Aravind .R

TI__Guru**** 191445 points

All I can do is give advice. It may be possible that the current layout will work, if it were me, I would make the changes. Why take a chance?

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Need help on schematics/layout verification based on TPS54560-Q1