LT1173
Micropower
DC/DC Converter
Adjustable and Fixed 5V, 12V
FEATURES
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DESCRIPTIO
Operates at Supply Voltages From 2.0V to 30V
Consumes Only 110µA Supply Current
Works in Step-Up or Step-Down Mode
Only Three External Components Required
Low Battery Detector Comparator On-Chip
User-Adjustable Current Limit
Internal 1A Power Switch
Fixed or Adjustable Output Voltage Versions
Space Saving 8-Pin MiniDIP or SO8 Package
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.
APPLICATI
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Flash Memory Vpp Generators
3V to 5V, 5V to 12V Converters
9V to 5V, 12V to 5V Converters
LCD Bias Generators
Peripherals and Add-On Cards
Battery Backup Supplies
Laptop and Palmtop Computers
Cellular Telephones
Portable Instruments
and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation.
TYPICAL APPLICATI
L1*
100µH
5V
IN
47Ω
I
LIM
10
µ
F
V
IN
SW1
S
VPP Output
12V
100mA
Logic Controlled Flash Memory VPP Generator
1N5818
V
OUT
5V/DIV
1.07M
†
+
+
LT1173
FB
SW2
SANYO
OS-CON
100
µ
F
0V
GND
124k
†
PROGRAM
5V/DIV
5ms/DIV
1173 TA02
1N4148
PROGRAM
LT1173 • TA01
*L1 = GOWANDA GA20-103K
COILTRONICS CTX100-4
NO OVERSHOOT
EFFICIENCY = 81%
†
= 1% METAL FILM
U
UO
UO
1
LINER [ LINEAR TECHNOLOGY ]
