LTC3775 View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LTC3775

High Frequency Synchronous Step-Down Voltage Mode DC/DC Controller

Linear Technology 

LTC3775

TYPICAL APPLICATIONS

24V Input, 12V/5A Output at 500kHz

R4

69.8k

R5

10k

RILIMT

1.24k

RILIMB

56.2k

CVCC

4.7μF

CSS

0.01μF

RSET

39.2k

C3

330pF

R3

RA

2.05k 191k

C2

330pF

RB

10k

R2

C1 7.68k

3.3nF

COUT: SANYO 16TQC68M

DB: CMDSH4E

L1: IHLP-4040DZ-ER-4R7-M11

QB, QT: RJK0305DPB-00-JO

DB

ILIMT VIN

TG

ILIMB

SENSE

INTVCC BOOST

LTC3775

SS

SW

FREQ

BG

RUN/SHDN

FB

PGND

MODE/SYNC

COMP

SGND

VIN

+ CIN1 24V

330μF

35V

QT

CB

0.1μF

L1

4.7μH

+

QB

COUT

68μF

16V

s2

VOUT

12V

5A

3775 TA04

Efficiency and Power Loss

vs Load Current

100

2.5

90

VIN = 24V

VOUT = 12V

80

CONTINUOUS MODE

SW FREQ = 500kHz

2.0

70

60

1.5

EFFICIENCY

50

40

1.0

POWER LOSS

30

20

0.5

10

0

0

0.01

0.1

1

10

LOAD CURRENT (A)

3775 TA04b

VOUT(AC)

200mV/DIV

Load Step

IL

5A/DIV

VIN = 24V

50μs/DIV

VOUT = 12V

LOAD = 0A TO 5A TO 0A

MODE = 0V

SW FREQ = 500kHz

Start-Up

VOUT

5V/DIV

IL

5A/DIV

SWITCHOVER

FROM PULSE-

SKIPPING TO

CONTINUOUS

MODE

VSS

1V/DIV

3775 TA04c

VIN = 24V

VOUT = 12V

CSS = 0.01μF

2ms/DIV

MODE = 0V

SW FREQ = 500kHz

3775 TA04d

3775fa

30

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