WEBENCH® Tools/BQ76PL455A-Q1: BQ76PL455A-Q1 Daisy chain Layout

Chien Hsun Kuan

Prodigy 60 points

Part Number: BQ76PL455A-Q1

Tool/software: WEBENCH® Design Tools

I have some question about BQ76PL455A-Q1 daisy chain Layout .

In Spec. daisy chain PCB layout need isolation keep out in top/ middle/ bottom layer.

http://www.ti.com/lit/an/slua791a/slua791a.pdf

But in EVM bottom layer didn't do that.

http://www.ti.com/lit/df/tidrhk4/tidrhk4.pdf

Please tell me which one is correct.

Best Regards,

Jason Kuan

over 6 years ago

0 Leslie Marquez over 6 years ago

TI__Genius 9401 points

Hi Jason,

Welcome to the forum! The best approach is to have a keep-out region on all PCB layers for your daisy chain components. Please follow the recommendations on the bq76PL455A-Q1 Design Recommendations document section 16.1: http://www.ti.com/lit/an/slua791a/slua791a.pdf

Best regards,

Leslie

0 Chien Hsun Kuan over 6 years ago in reply to Leslie Marquez

Prodigy 60 points

Dear Leslie

Thanks for your reply.

I still have some question can't understand.

In this case, if keep-out region on all PCB layers how to make current flows in a closed loop ?

Best regards,

Jason Kuan

0 Leslie Marquez over 6 years ago in reply to Chien Hsun Kuan

TI__Genius 9401 points

Hi Jason,

These signals are differential, so the current return path is through the opposite differential line (e.g. COMH+ returns through COMH-).

Regards,

Leslie

Power management

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WEBENCH® Tools/BQ76PL455A-Q1: BQ76PL455A-Q1 Daisy chain Layout