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TPS51220A: layout guide design

Tommy Tzeng
Genius 5065 points
Part Number: TPS51220A
Other Parts Discussed in Thread: TPS51220

Hi Sir,

may we learn from you, 

Please refer to below schematic and layout design.

there are some design concepts needed discuss

 

         we design TPS51220 for +V5A at PHASE1

        about the VIN ceramic bypass / High side Q10 / low side Q11 / output bypass ceramic and EC4

        Question1

        case I : the VIN was provided from internal layer through the via (yellow arrow)

        case II: change those via holes from current location(yellow arrow) to high side Q10 Drain thermal pad

        above design concept, which one can provide better power quality and reduce ESR/ESL

        if there are any better location for those via holes, please suggest! thanks

 

        Question2:

        About the output by-pass solid Capacitor

        Should we add some GND via for EC4 and output ceramic for power return path?

       Question3:

        PCB TOP side EC4, should we design pattern at TOP side under EC4?

  • 0
    TI__Mastermind 18510 points

    Hi Tommy,

    Q1, To reduce the ESL, closer to caps pins are useful, and for high power quality, vias added under FET thermal pad will be useful, which is more helpful for thermal dissipation, so recommend to add vias for both.

    Q2/Q3: More vias will be better and suggest close to pins as well, and since the current is lower, pattern at top layer should not be needed.

    BTW, suggest to enlarge the gaps between SW net and output under inductor.

    Yuchang