LT1619 データシートの表示（PDF） - Linear Technology

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LT1619

Low Voltage Current Mode PWM Controller

Linear Technology 

FEATURES

s Wide VIN Range: 1.9V to 18V

s 300kHz Fixed Frequency Current Mode Control

s 1A Rail-to-Rail N-Channel MOSFET Driver

s Low 53mV Current Limit Threshold Voltage

Improves Efficiency

s Implements Boost, SEPIC and Flyback Converters

Requiring Low Side Power Transistors

s Internal Current Sense Amplifier

with Leading Edge Blanking

s Up to 500kHz External Synchronization

s Burst ModeTM Operation for High Efficiency

at Light Load

s 140µA Quiescent Current

s 15µA Shutdown Current

s 8-Lead MSOP and SO Packages

U

APPLICATIO S

s 3.3V to 5V DC/DC Converters

s Distributed Power Supplies

s Isolated Power Supplies

LT1619

Low Voltage Current Mode

PWM Controller

DESCRIPTIO

The LT®1619 is a fixed frequency PWM controller for

implementing current mode DC/DC converters with mini-

mum external parts. The LT1619 operates with input

voltage ranging from 1.9V to 18V and is suitable for a

variety of battery-powered and distributed DC/DC con-

verters. The internal rail-to-rail N-channel MOSFET driver

operates either from the input in the nonbootstrapped

mode or from the output in bootstrapped operation. The

driver is designed to drive a low side power transistor in

boost, SEPIC, flyback and other topologies.

Converter efficiency is improved at heavy loads with a

53mV current sense voltage and at light load with Burst

Mode operation. The operating frequency is internally set

at 300kHz. The oscillator can also be synchronized exter-

nally up to 500kHz. No load quiescent current is 140µA and

shutdown current is 15µA.

The LT1619 is available in 8-lead MSOP and SO packages.

, LTC and LT are registered trademarks of Linear Technology Corporation.

Burst Mode is a trademark of Linear Technology Corporation.

TYPICAL APPLICATIO

R2

12.4k

R1

37.4k

220pF

75k

15nF

1

S/S

8

VIN

2

FB

7

DRV

LT1619

3

6

VC

GATE

4

5

GND SENSE

C1: PANASONIC EEFCDOK220R

COUT: KEMET T495X227K010AS (×2)

D1: MBRD835L

L1: COILCRAFT DO5022P-562

+ C1

0.1µF

22µF

0.1µF

VIN

3.3V

L1

5.6µH

5A

M1

D1

Si9804

+

RSENSE

0.01Ω

1619 F01

VOUT

5V

2.2A

COUT

440µF

Figure 1. High Efficiency 3.3V to 5V DC/DC Converter

Efficiency

95

90

85

80

75

70

1

10

100

LOAD CURRENT (mA)

1000

1619 F01a

1

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