LT1303 Datasheet, PDF (1/12 Pages) Linear Technology – Micropower High Efficiency DC/DC Converters with Low-Battery Detector Adjustable and Fixed 5V

LT1303/LT1303-5
Micropower High Efficiency
DC/DC Converters with
Low-Battery Detector
Adjustable and Fixed 5V
FEATURES
s _{5V at 200mA from a 2V Input}
s _{Supply Voltage As Low As 1.8V}
s _{Up to 88% Efficiency}
s _{120µA Quiescent Current}
s _{Low-Battery Detector}
s _{Low VCESAT Switch: 170mV at 1A Typ}
s _{Uses Inexpensive Surface Mount Inductors}
s _{8-Lead PDIP or SO Package}
U
APPLICATIONS
s _{EL Panel Drivers}
s _{2-Cell and 3-Cell to 5V Conversion}
s _{Palmtop Computers}
s _{Portable Instruments}
s _{Bar-Code Scanners}
s _PDAs
s _{Wireless Systems}
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.
TYPICAL APPLICATION
L1
22µH
1N5817
+
2 CELLS
100µF
316k
1%
412k
1%
SHUTDOWN
V_IN
LBI
SW
SENSE
LT1303-5
100k
SHDN
GND
LBO
PGND
+
100µF
V_OUT, 5V
200mA
LOW BATTERY
GOES LOW AT
V_BAT = 2.2V
L1 = SUMDIA CD54-220
LT1303 TA02
Figure 1. 2-Cell to 5V DC/DC Converter with Low-Battery Detect
90
80
70
60
50
40
30
0.1
5V Output Efficiency
V_IN = 4V
V_IN = 2.5V
V_IN = 3V
V_IN = 2V
1
10
100
1000
LOAD CURRENT (mA)
LT1303 TA01
1