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TPS55287: Using TPS55287 to Power RF PA Collector – Schematic Check and TPS55289 Drop-In Question

Hao Lennart
Prodigy 10 points
Part Number: TPS55287
Other Parts Discussed in Thread: TPS55289

Hi,

I’m planning to use TPS55287 to supply the collector of an RF power amplifier and would like a quick sanity check on the schematic (attached).

Setup

  • Output: 5–12 V adjustable

  • Regulation: internal reference

  • Current sense: disabled

  • Load: RF PA collector (dynamic / pulsed current)

  • No digital control, voltage only

Questions

  1. From a power integrity and stability standpoint, is TPS55287 suitable for directly powering an RF PA collector?

  2. With the PA’s dynamic current, do you see any issues with control loop stability or transient response?

  3. Is additional isolation recommended between the converter and the collector (LDO, ferrite bead, LC filter), or is direct connection acceptable with proper output decoupling?

  4. Current sense is not used in this design — any concerns with that configuration?

  5. I only have TPS55289 available:

    • Is TPS55289 pin-to-pin compatible with TPS55287?

    • Can it be used as a drop-in replacement without PCB changes?

Any feedback is appreciated.

Thanks,

Lennart

  • 0
    TI__Mastermind 31055 points

    Hello, we have received your case and the investigation will take some time. Thank you for your patience.

  • 0 回复 Eirwen
    Prodigy 10 points

    Sorry about that — it looks like the images didn’t get uploaded in my previous message.

    Please find the latest schematic attached here.

  • 0 回复 Hao Lennart
    TI__Mastermind 41700 points

    1. 2.  Can you provide the load profile for me to evaluate?

    3. Can you provide the load profile for me to evaluate?

    4.  It is ok to directly short ISP and ISN to Vout if not used.

    5.  

    TPS55289 and TPS55287 are pin-to-pin. The only difference is TPS55289 has 8A average current limit and TPS55287 has 4A average current limit. To design the PCB to be compatible with both IC, you need to use an inductor with Isat>8A.

    For the schematic, compensation parameters should be optimized with your BOM and working condition. Recommend to reserve external feedback resistor option to do bench test to evaluate compensation parameters. Others looks good to me.