LT1304/LT1304-3.3/LT1304-5
Micropower
DC/DC Converters with
Low-Battery Detector
Active in Shutdown
FEATURES
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DESCRIPTION
The LT
®
1304 is a micropower step-up DC/DC converter
ideal for use in small, low voltage, battery-operated sys-
tems. The devices operate from a wide input supply range
of 1.5V to 8V. The LT1304-3.3 and LT1304-5 generate
regulated outputs of 3.3V and 5V and the adjustable
LT1304 can deliver output voltages up to 25V. Quiescent
current, 120µA in active mode, decreases to just 10µA in
shutdown with the low-battery detector still active. Peak
switch current, internally set at 1A, can be reduced by
adding a single resistor from the I
LIM
pin to ground. The
high speed operation of the LT1304 allows the use of
small, surface-mountable inductors and capacitors. The
LT1304 is available in an 8-lead SO package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
5V at 200mA from Two Cells
10µA Quiescent Current in Shutdown
Operates with V
IN
as Low as 1.5V
Low-Battery Detector Active in Shutdown
Low Switch V
CESAT
: 370mV at 1A Typical
120µA Quiescent Current in Active Mode
Switching Frequency Up to 300kHz
Programmable Peak Current with One Resistor
8-Lead SO Package
APPLICATIONS
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2-, 3-, or 4-Cell to 5V or 3.3V Step-Up
Portable Instruments
Bar Code Scanners
Palmtop Computers
Diagnostic Medical Instrumentation
Personal Data Communicators/Computers
TYPICAL APPLICATION
2-Cell to 5V Step-Up Converter with Low-Battery Detect
22µH*
3
V
IN
LBI
4
SW
SENSE
LT1304-5
6
I
LIM
SHDN
7
SHUTDOWN
*SUMIDA CD54-220
**1N5817
1304 TA01
D1**
90
499k
1
8
100k
2 CELLS
100µF
604k
NC
100µF
LBO
LOW WHEN
V
BAT
< 2.2V
EFFICIENCY (%)
+
+
5V
200mA
80
70
LBO
GND
5
2
60
V
IN
= 3.3V
V
IN
= 2.5V
V
IN
= 1.8V
1
10
100
LOAD CURRENT (mA)
500
1304 TA02
50
40
0.1
U
U
U
Efficiency
1
LINER [ LINEAR TECHNOLOGY ]
