LM3489: Dynamic performance improvement question

Oliver Lin

Part Number: LM3489

Hi team,

Following from the thread below,

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1227570/lm3489-asking-for-lm3489-audible-noise-design-review-and-suggestions

Customer test spec that will need to draw 9A for 1s, and see this voltage drop below 18V(customer spec). but changing inductor into 2.2uH, dynamic performance can be improved, is this any potential risk to have to change on inductor? Or we have other components can be modified? Thank you.

L7201 = 10uH

L7201 = 2.2uH

over 1 year ago

0 Jimmy Hua over 1 year ago

TI__Guru 50120 points

Hello,

I would suggest sticking to the 10uH as this is similar to the USB Type C reference design using the LM3489

https://www.ti.com/lit/ug/slvubj5/slvubj5.pdf

To reduce undershoot during load transient, I would increase output capacitance by 100uF-200uF. Given that this is a hysteretic controller, adding more output capacitance should slow down the load transient response time and improve voltage deviation.

Regards,

Jimmy

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LM3489: Dynamic performance improvement question