1
LT1300
■
Up to 220mA Output Current at 5V from 2V Supply
■
Supply Voltage as Low as 1.8V
■
Up to 88% Efficiency
■
Small Inductor –10
µ
H
■
120
µ
A Quiescent Current
■
Shutdown to 10
µ
A
■
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
■
Palmtop Computers
■
Portable Instruments
■
Bar-Code Scanners
■
DC/DC Converter Module Replacements
■
Battery Backup Supplies
■
Personal Digital Assistants
■
PCMCIA Cards
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 120
µ
A and a shutdown pin which
reduces supply current to 10
µ
A. 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.
DESCRIPTIO
N
U
FEATURES
TYPICAL APPLICATIO
N
S
N
U
Micropower High Efficiency
3.3/5V Step-Up DC/DC Converter
APPLICATIO
N
S
U
Two-Cell to 3.3V/5V Step-Up Converter
5V Output Efficiency
L1 = COILCRAFT DO1608-103
OR SUMIDA CD54-100
C1 = AVX TPSD107M010R0100
OR SANYO OS-CON 16SA100M
D1 = MBRS130LT3
OR 1N5817
C1
100µF
5V/3.3V
OUTPUT
+
+
L1
10µH
D1
C1
100µF
2
×
AA
CELL
SW
I
LIM
PGND
GND
SENSE
LT1300
SELECT
LT1300 TA1
5V/3.3V
SELECT
SHDN
SHUTDOWN
N/C
2
6
7
4
5
8
1
3
V
IN
LOAD CURRENT (mA)
10
100
500
LT1300 TA2
1
74
EFFICIENCY (%)
76
78
80
82
90
84
86
88
V
IN
= 4.0V
V
IN
= 3.0V
V
IN
= 2.5V
V
IN
= 2.0V
Burst Mode is a trademark of Linear Technology Corporation.
