LT1304-5_15 Datasheet, PDF (1/16 Pages) Linear Technology – Micropower DC/DC Converters with Low-Battery Detector Active in Shutdown

LT1304/LT1304-3.3/LT1304-5
Micropower
DC/DC Converters with
Low-Battery Detector
Active in Shutdown
FEATURES
s _{5V at 200mA from Two Cells}
s _{10µA Quiescent Current in Shutdown}
s _{Operates with VIN as Low as 1.5V}
s _{Low-Battery Detector Active in Shutdown}
s _{Low Switch VCESAT: 370mV at 1A Typical}
s _{120µA Quiescent Current in Active Mode}
s _{Switching Frequency Up to 300kHz}
s _{Programmable Peak Current with One Resistor}
s _{8-Lead SO Package}
U
APPLICATIONS
s _{2-, 3-, or 4-Cell to 5V or 3.3V Step-Up}
s _{Portable Instruments}
s _{Bar Code Scanners}
s _{Palmtop Computers}
s _{Diagnostic Medical Instrumentation}
s _{Personal Data Communicators/Computers}
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.
TYPICAL APPLICATION
2-Cell to 5V Step-Up Converter with Low-Battery Detect
22µH*
D1**
+
2 CELLS
100µF
*SUMIDA CD54-220
**1N5817
499k
3
V_IN
1
LBI
4
SW
8
SENSE
LT1304-5
604k
6
NC I_LIM
2
LBO
SHDN
GND
7
5
SHUTDOWN
+
100k
5V
200mA
100µF
LBO
LOW WHEN
V_BAT < 2.2V
1304 TA01
90
80
70
60
50
40
0.1
Efficiency
V_IN = 3.3V
V_IN = 2.5V
V_IN = 1.8V
1
10
100 500
LOAD CURRENT (mA)
1304 TA02
1