NB650/NB650H

– 6A, 28V, FAST TRANSIENT SYNCHRONOUS STEP-DOWN CONVERTER

NB650/NB650H Rev. 1.13

www.MonolithicPower.com

16

10/7/2019

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

Preliminary Specifications Subject to Change

© 2019 MPS. All Rights Reserved.

12mΩ is required to ensure stable operation of

the converter. For simplification, the output ripple

can be approximated as:

OUT

OUT

OUT

ESR

SW

IN

VV

V

(1

) R

f

L

V





 





(32)

Inductor

The inductor supplies constant current to the

output load while being driven by the switching

input voltage. A larger value inductor results in

less ripple current, which results in lower output

ripple voltage. However, a larger value inductor is

physically larger, has a higher series resistance,

and/or lower saturation current. To determine the

inductor value, allow the inductor peak-to-peak

ripple current to reach approximately 30% to 40%

of the maximum switch current limit. Make sure

that the peak inductor current is below the

maximum switch current limit. The inductance

value can be calculated as:

OUT

OUT

SW

L

IN

VV

L

(1

)

f

I

V



 



(33)

Where ΔIL is the peak-to-peak inductor ripple cur

rent.

Choose an inductor that will not saturate under

the maximum inductor peak current. The peak

inductor current can be calculated as:

OUT

OUT

LP

OUT

SW

IN

VV

I

I

(1

)

2f

L

V





 



(34)