LP3958

SNVS423C – JANUARY 2006 – REVISED MARCH 2013

www.ti.com

INDUCTOR, L1

A 10uH shielded inductor is suggested for LP3958 boost converter. The inductor should have a saturation

current rating higher than the rms current it will experience during circuit operation (600mA). Less than 300m

Ω

ESR is suggested for high efficiency and sufficient output current. Open core inductors cause flux linkage with

circuit components and interfere with the normal operation of the circuit. This should be avoided. For high

efficiency, choose an inductor with a high frequency core material such as ferrite to reduce the core losses. To

minimize radiated noise, use a toroid, pot core or shielded core inductor. The inductor should be connected to

the SW pin as close to the IC as possible. Examples of suitable inductors are: TDK VLF4012AT-100MR79,

VLF4018BT-100MR90, VLF5014AT-100MR92, Coilcraft LPS4018-103ML.

LIST OF RECOMMENDED EXTERNAL COMPONENTS

Symbol

Symbol Explanation

Value

Unit

Type

CVDD

C between VDD1,2 and GND

100

nF

Ceramic, X7R / X5R

CVDDIO

C between VDDIO and GND

100

nF

Ceramic, X7R / X5R

CVDDA

C between VDDA and GND

1

µF

Ceramic, X7R / X5R

C between FB and GND

2 x 4.7 or 1 x

µF

Ceramic, X7R / X5R, tolerance

10

COUT

±10%

Maximum DC bias effect @ 18V

-50

%

CIN

C between battery voltage and GND

10

µF

Ceramic, X7R / X5R

L between SW and VBAT

10

µH

L1

Shielded inductor, low ESR

Saturation current

600

mA

CVREF

C between VREF and GND

100

nF

Ceramic, X7R / X5R

RKEY

R between IKEY and GND

8.2

k

Ω

±1%

RRT

R between IRT and GND

82

k

Ω

±1%

Rectifying diode (Vf @ maxload)

0.3-0.5

V

D1

Reverse voltage

30

V

Schottky diode

Repetitive peak current

800

mA

CSW

C in EMI filter

100

pF

Ceramic, X7R / X5R, 50V

RSW

R in EMI filter

390

Ω

±1%

LEDs

User Defined

Note: See Application Note AN-1436 "Design and Programming Examples for Lighting Management Unit

LP3958" for more information on how to design with LP3958

24

Submit Documentation Feedback

Copyright © 2006–2013, Texas Instruments Incorporated

Product Folder Links: LP3958