TPS56637: Phase Margin - Gain crossover doesn't reach 0dB

Tool/software:

Hi team,

I tried to measure the phase margin of the TPS56637, but noticed that the gain never reaches 0 dB. It is confusing because the Bode plot looked fine when I measured the TPS62A02 on the same board.

Could you advise if there’s anything I might be doing incorrectly? I even put a 0.22 Cpass parallel to the Rinjection because TPS56637 is DCAP, But it didn't improve the result.

Test condition:

• Vin: 23V
• Vout: 12V
• Iout: 5A

Below is the Bode plot capture withTPS62A02 on the same PCB. As you can see, there seems no issue with phase margin.

Thanks,

Jay