LT1173_15 Datasheet, PDF (1/16 Pages) Linear Technology – Micropower DC/DC Converter Adjustable and Fixed 5V, 12V

FEATURES
s _{Operates at Supply Voltages From 2.0V to 30V}
s _{Consumes Only 110µA Supply Current}
s _{Works in Step-Up or Step-Down Mode}
s _{Only Three External Components Required}
s _{Low Battery Detector Comparator On-Chip}
s _{User-Adjustable Current Limit}
s _{Internal 1A Power Switch}
s _{Fixed or Adjustable Output Voltage Versions}
s _{Space Saving 8-Pin MiniDIP or SO8 Package}
APPLICATI S
s _{Flash Memory Vpp Generators}
s _{3V to 5V, 5V to 12V Converters}
s _{9V to 5V, 12V to 5V Converters}
s _{LCD Bias Generators}
s _{Peripherals and Add-On Cards}
s _{Battery Backup Supplies}
s _{Laptop and Palmtop Computers}
s _{Cellular Telephones}
s _{Portable Instruments}
LT1173
Micropower
DC/DC Converter
Adjustable and Fixed 5V, 12V
DESCRIPTIO
The LT1173 is a versatile micropower DC-DC converter.
The device requires only three external components to
deliver a fixed output of 5V or 12V. Supply voltage ranges
from 2.0V to 12V in step-up mode and to 30V in step-down
mode. The LT1173 functions equally well in step-up, step-
down or inverting applications.
The LT1173 consumes just 110µA supply current at
standby, making it ideal for applications where low quies-
cent current is important. The device can deliver 5V at
80mA from a 3V input in step-up mode or 5V at 200mA
from a 12V input in step-down mode.
Switch current limit can be programmed with a single
resistor. An auxiliary gain block can be configured as a low
battery detector, linear post regulator, under voltage lock-
out circuit or error amplifier.
For input sources of less than 2V, use the LT1073.
and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation.
TYPICAL APPLICATI S
Logic Controlled Flash Memory VPP Generator
L1*
5V_IN
100µH
1N5818
12V
100mA
47Ω
+
10 µ F
I_LIM
V _IN
SW1
LT1173
FB
GND
SW2
1.07M^†
+
SANYO
OS-CON
100 µ F
124k^†
PROGRAM
1N4148
*L1 = GOWANDA GA20-103K
COILTRONICS CTX100-4
NO OVERSHOOT
EFFICIENCY = 81%
† _{= 1% METAL FILM}
LT1173 • TA01
V_OUT
5V/DIV
0V
PROGRAM
5V/DIV
VPP Output
5ms/DIV
1173 TA02
1