BQ25504: Questions about reference design

LzBone

Intellectual 770 points

Part Number: BQ25504

Hi,

I am new to PCB design and would like to ask following for BQ25504 reference design.

Q1. Why inductor L1 has to be as close as possible to the chip?

Q2. Why input tracks has to be thick lines?

Q3. Why there is a need for top and bottom ground planes? Will it work without ground planes?

Q4. For resistors and capacitors, is it ok if I choose larger or smaller size than 0805, as long as its values are as per data sheet recommendation?

Thanks a lot.

Regards,

over 7 years ago

0 Raheem over 7 years ago

TI__Mastermind 21590 points

Hello,
Q1: The inductor needs to be close to the IC to reduce resistance which could cause power loss.
Q2: The input track needs to have thick lines to support the input currents.
Q3: This is explained in section 11.1 of the datasheet. It is to prevent ground shifting.
Q4: It is ok as long as you meet the datasheet requirements.

Regards,
Raheem