1

LT1307/LT1307B

Single Cell Micropower

600kHz PWM DC/DC Converters

FEATURES

The LT

DC/DC converters that operate from an input voltage as

low as 1V. First in the industry to achieve true current

mode PWM performance from a single cell supply, the

LT1307 features automatic shifting to power saving Burst

Mode operation at light loads. High efficiency is main-

tained over a broad 100

µA to 100mA load range. The

LT1307B does not shift into Burst Mode operation at light

loads, eliminating low frequency output ripple at the

expense of light load efficiency. The devices contain a low-

battery detector with a 200mV reference and shut down to

less than 5

µA. No load quiescent current of the LT1307 is

50

µA and the internal NPN power switch handles a 500mA

current with a voltage drop of just 295mV.

Unlike competitive devices, large electrolytic capacitors

are

not required with the LT1307/LT1307B in single cell

applications. The high frequency (600kHz) switching al-

lows the use of tiny surface mount multilayer ceramic

(MLC) capacitors along with small surface mount induc-

tors. The devices work with just 10

µF of output capaci-

tance and require only 1

µF of input bypassing.

The LT1307/LT1307B are available in 8-lead MSOP, PDIP

and SO packages.

s

Uses Small Ceramic Capacitors

s

50

µA Quiescent Current (LT1307)

s

1mA Quiescent Current (LT1307B)

s

s

600kHz Fixed Frequency Operation

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Starts into Full Load

s

Low Shutdown Current: 3

µA

s

Low-Battery Detector

s

3.3V at 75mA from a Single Cell

s

Automatic Burst Mode

Light Load (LT1307)

s

Continuous Switching at Light Load (LT1307B)

s

s

Pagers

s

Cordless Telephones

s

GPS Receivers

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Battery Backup

s

Portable Electronic Equipment

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Glucose Meters

s

Diagnostic Medical Instrumentation

Burst Mode is a trademark of Linear Technology Corporation.

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

Single Cell to 3.3V Converter Efficiency

LOAD CURRENT (mA)

0.1

70

80

90

1

10

100

1307 TA01

60

50

SW

FB

LT1307

L1

10

µH

D1

LBO

LBI

SHDN

SHUTDOWN

100k

R2

604k

1%

3.3V

75mA

R1

1.02M

1%

680pF

FOR 5V OUTPUT: R1 = 1M, R2 = 329k

C1: MURATA-ERIE GRM235Y5V105Z01

MARCON THCS50E1E105Z

TOKIN 1E105ZY5U-C103-F

C2: MURATA-ERIE GRM235Y5V106Z01

MARCON THCS50E1E105Z

TOKIN 1E106ZY5U-C304-F

1307 F01

C1

1

µF

C2

10

µF

1.5V

CELL

GND

D1: MOTOROLA MBR0520L

L1: COILCRAFT D01608C-103

SUMIDA CD43-100

MURATA ERIE LQH3C100

Figure 1. Single Cell to 3.3V Boost Converter