LT1303/LT1303-5
Micropower High Efficiency
DC/DC Converters with
Low-Battery Detector
Adjustable and Fixed 5V
FEATURES
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DESCRIPTION
The LT
®
1303/LT1303-5 are micropower step-up high
efficiency DC/DC converters using Burst Mode
TM
opera-
tion. They are ideal for use in small, low-voltage battery-
operated systems. The LT1303-5 accepts an input voltage
between 1.8V and 5V and converts it to a regulated 5V. The
LT1303 is an adjustable version that can supply an output
voltage up to 25V. Quiescent current is only 120µA from
the battery and the shutdown pin further reduces current
to 10µA. The low-battery detector provides an open-
collector output that goes low when the input voltage
drops below a preset level. The on-chip NPN power switch
has a low 170mV saturation voltage at a switch current
of 1A. The LT1303/LT1303-5 are available in 8-lead PDIP
or SO packages, easing board space requirements.
For higher output current, please see the LT1305 or
LT1302.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
5V at 200mA from a 2V Input
Supply Voltage As Low As 1.8V
Up to 88% Efficiency
120
µ
A Quiescent Current
Low-Battery Detector
Low V
CESAT
Switch: 170mV at 1A Typ
Uses Inexpensive Surface Mount Inductors
8-Lead PDIP or SO Package
APPLICATIONS
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EL Panel Drivers
2-Cell and 3-Cell to 5V Conversion
Palmtop Computers
Portable Instruments
Bar-Code Scanners
PDAs
Wireless Systems
TYPICAL APPLICATION
L1
22µH
316k
1%
1N5817
90
80
V
IN
LBI
SW
SENSE
LT1303-5
100k
LBO
PGND
100µF
EFFICIENCY (%)
+
2 CELLS
100µF
V
OUT
, 5V
200mA
LOW BATTERY
GOES LOW AT
V
BAT
= 2.2V
412k
1%
SHUTDOWN
SHDN
GND
70
60
50
40
+
L1 = SUMDIA CD54-220
LT1303 TA02
30
Figure 1. 2-Cell to 5V DC/DC Converter with Low-Battery Detect
U
U
U
5V Output Efficiency
V
IN
= 4V
V
IN
= 2V
V
IN
= 2.5V
V
IN
= 3V
0.1
1
10
100
1000
LT1303 TA01
LOAD CURRENT (mA)
1
LINER [ LINEAR TECHNOLOGY ]
