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gautam023 , 07-20-2021, 04:03 AM

Hello everyone,

I am new to PCB design and would like to get some advice on my design. The project is a PDU using an LT3958 IC in SEPIC mode to get +15V and +5V from a 68V battery pack and LTC3630A in inverting mode to get -15V from the same battery pack.

I used only 2 layers for the design. Should I be using 4 layers or will 2 layers do just fine?

Design files are also attached here . The software used is Eagle.

robertferanec , 07-20-2021, 04:48 AM

I am always careful, so my advice may be too safe: If you do not have experience with power supply design and you would need to pass EMC/EMI, then a 4 layer PCB may help. If you would have experience or if your product has to be super cheap, 2 layer PCB is usually fine but sometimes you may need to do some tweaking.

If you only need it for your own project (no EMC/EMI testing required), a two layer PCB will probably work ok.

qdrives , 07-21-2021, 05:52 PM

Just a few to start...

• Keep the switch nodes as small and short as possible.
• Place more Gnd via's, they are almost free. Like one for each component/pin.
• Perhaps more thermal relieves are needed. Keep copper balance to prevent tomb stoning.
• You can leave the polygon pour cutout. Clearances should take care of it.
• You have not provided schematic, so I cannot really check the circuit, but -15V seems wrong.
• Why did you go for SEPIC? if the input power is (way) higher, just go for buck - it is less problematic.