LTC3458L

8

3458lf

Detailed Description

The LTC3458L provides high efficiency, low noise power

for boost applications with output voltages up to 6V. The

true output disconnect feature eliminates inrush current,

current mode architecture with adaptive slope compensa-

tion provides ease of loop compensation with excellent

synchronous switches eliminate the need for an external

Schottky rectifier, and provide efficient high frequency

pulse width modulation (PWM) control. High efficiency is

achieved at light loads when Burst Mode operation is

entered, where the IC’s quiescent current is a low 12

µA

custom performance in a variety of applications with

programmable feedback, current limit, oscillator frequency,

soft-start, and Burst Mode threshold.

BLOCK DIAGRA

PGND

PGND

3

6

9

OSC/SYNC

MAX

DUTY

SYNC

GND

PGND

SS

COMP

SHDN

SW

FB

BURST

PWM

AND

BURST MODE

DRIVE LOGIC

P-DRIVE

P-DRIVE

P-DRIVE

N-DRIVE

N-DRIVE

N-DRIVE

DETECT

BURST MODE

CONTROL

FIXED

FREQUENCY

BURST MODE

MUX

SOFT-START

THERMAL SD

4%

UNDERVOLTAGE

REFERENCE/

BIAS

PEAK CURRENT

COMPARATOR

SLOPE COMP

SLEEP

SLEEP

CONTROL

MODE

MODE

MODE

SLOPE

SLOPE

SLEEP TO

ALL BLOCKS

I_SENSE

BURST ACTIVE

(DISABLED IN

BURST MODE)

+

–

+

–

TSD

5

13

10

8

4

11

1

2

12

7

ANTIRING

SW1

UNDER

UNDER

SD

TO ALL BLOCKS

SDB

BIAS

CURRENTS

UVLO

3458L BD

ERROR AMPLIFIER/

BURST COMPARATOR

APPLICATIO S I FOR ATIO

LTC3458L Programmable Functions

The programmable current limit circuit sets the maximum

peak current in the internal N-channel MOSFET switch.

This clamp level is programmed using a resistor to ground

automatically set to ~1/4 of the programmed current limit

mended in most applications unless a lower limit is

needed to prevent the external inductor from saturating.

I

R

180

I is in amps and R is in k

Ω.

II

BURSTPEAK

LIM

≈

1

4

•