LM46002 phase margin 102 degree - Whether design is stable

Arun Kuna

Other Parts Discussed in Thread: LM46002

Found LM46002 part in Webench for 3.3V conversion from 6 to 34 V input .But in simulation result we found phase margin is 102, which seems too higher than recommended( 45 to 60 degree), Kindly suggest its impact and possibilities to tune it. Load current is 1.55A.

over 9 years ago

0 Frank De Stasi over 9 years ago

TI__Guru 72035 points

The simulation may not always give exactly correct results; however Webench should give a stable design.

I will pass this to the
Webench team.

0 Kevin Ip over 9 years ago in reply to Frank De Stasi

TI__Intellectual 2155 points

Hi Arun,

The BOM you have from WEBENCH should give a stable design.

If you would like to reduce the phase margin, try choosing a smaller ESR value output capacitor from the alternate BOM components list.

You can also try using the WEBENCH Compesation Designer. In your WEBENCH design, click on the "Re-Comp" icon to recompensate your design and tune it further.

0 Arun Kuna over 9 years ago in reply to Kevin Ip

Prodigy 50 points

HI Kevin,
Thanks for your suggestion. I changed the phase margin by changing output capacitors . I want to know what will be the impact on system if the phase margin exceeds 60 degree and why webench suggesting design will be stable.

Power management

Power management forum

LM46002 phase margin 102 degree - Whether design is stable