1

LT1301

s

12V at 120mA from 5V or 3.3V Supply

s

Supply Voltage as Low as 1.8V

s

Better High Current Efficiency Than CMOS

s

Up to 89% Efficiency

s

120

µA Quiescent Current

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Shutdown to 10

µA

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Programmable 5V or 12V Output

s

s

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Uses Inexpensive Surface Mount Inductors

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8-Lead DIP or SOIC Package

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Palmtop Computers

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Portable Instruments

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Bar-Code Scanners

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Personal Digital Assistants

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PCMCIA Cards

The LT1301 is a micropower step-up DC/DC converter that

utilizes Burst Mode™ operation. The device can deliver 5V

or 12V from a two-cell battery input. It features program-

mable 5V or 12V output via a logic-controlled input, no-

load quiescent current of 120

µAandashutdownpinwhich

reduces supply current to 10

µA.Theon-chippowerswitch

has a low 170mV saturation voltage at a switch current of

1A, a four-fold reduction over prior designs. A 155kHz

internal oscillator allows the use of extremely small sur-

face mount inductors and capacitors. Operation is guaran-

teed at 1.8V input. This allows more energy to be extracted

be used for soft start or to program peak switch current

with a single resistor allowing the use of even smaller

inductors in lighter load applications. The LT1301 is

available in an 8-lead SOIC package, minimizing board

space requirements. For a selectable 3.3V/5V step-up

converter, please see the LT1300. For higher output

power, see the LT1302.

FEATURES

Micropower High Efficiency

5V/12V Step-Up DC/DC

Converter for Flash Memory

LT1300 F2

Figure 1. 3.3V/5V to 12V Step-Up Converter

1ms/DIV

LOAD = 100

Ω

Output Voltage

12V

2V/DIV

LT1301 TAO1

Efficiency

LOAD CURRENT (mA)

10

100

300

LT1301 TA2

1

0

72

74

76

78

80

82

90

84

86

88

L1 = COILCRAFT DO3316-333

OR SUMIDA CD73-330KC

D1 = 1N5817 OR MOTOROLA

MBRS130LT3

C1 = AVX TPSD476M016R0100

OR SANYO OS-CON 165A47M

C2 = AVX TPSD336M020R0100

OR SANYO OS-CON 205A33M

SHUTDOWN

10V/DIV

Burst Mode is a trademark of Linear Technology Corporation.

C2

33µF

20V

12V

OUTPUT

+

L1

33µH

D1

C1

47µF

SW

PGND

GND

SENSE

LT1301

SELECT

LT1301 F1

5V

OR

3.3V

SHDN

SHUTDOWN

N/C

+

0.1µF*

*REQUIRED FOR 5V OUTPUT