LT1300
Micropower High Efficiency
3.3/5V Step-Up DC/DC Converter
FEATURES
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DESCRIPTION
The LT1300 is a micropower step-up DC/DC converter that
utilizes Burst Mode™ operation. The device can deliver 5V
or 3.3V from a two-cell battery input. It features program-
mable 5V or 3.3V output via a logic-controlled input, no-
load quiescent current of 120µA and a shutdown pin which
reduces supply current to 10µA. The on-chip power switch
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
from the battery increasing operating life. The I
LIM
pin can
be used to program peak switch current with a single
resistor allowing the use of less expensive and smaller
inductors and capacitors in lighter load applications. The
LT1300 is available in an 8-lead SOIC package, minimizing
board space requirements. For a 5V/12V Selectable Out-
put Converter see the LT1301. For increased output cur-
rent see the LT1302.
Burst Mode is a trademark of Linear Technology Corporation.
Up to 220mA Output Current at 5V from 2V Supply
Supply Voltage as Low as 1.8V
Up to 88% Efficiency
Small Inductor –10µH
120µA Quiescent Current
Shutdown to 10µA
Programmable 3.3V or 5V Output
I
LIM
Pin Programs Peak Switch Current
Low V
CESAT
Switch: 170mV at 1A Typical
Uses Inexpensive Surface Mount Inductors
8-Lead DIP or SOIC Package
APPLICATIONS
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Palmtop Computers
Portable Instruments
Bar-Code Scanners
DC/DC Converter Module Replacements
Battery Backup Supplies
Personal Digital Assistants
PCMCIA Cards
TYPICAL APPLICATIONS
N
Two-Cell to 3.3V/5V Step-Up Converter
L1
10µH
6
V
IN
5V/3.3V 2
SELECT
SELECT
LT1300
3
SHDN
PGND
8
I
LIM
GND
1
5
N/C
7
SW
SENSE
4
86
EFFICIENCY (%)
5V Output Efficiency
5V/3.3V
OUTPUT
90
88
V
IN
= 4.0V
V
IN
= 3.0V
V
IN
= 2.5V
V
IN
= 2.0V
D1
2×
AA
CELL
+
C1
100µF
SHUTDOWN
+
C1
100µF
84
82
80
78
L1 = COILCRAFT DO1608-103
OR SUMIDA CD54-100
C1 = AVX TPSD107M010R0100
OR SANYO OS-CON 16SA100M
D1 = MBRS130LT3
OR 1N5817
LT1300 TA1
76
74
1
10
100
LOAD CURRENT (mA)
500
LT1300 TA2
U
U
U
1
LINER [ LINEAR TECHNOLOGY ]
