LT1110
Micropower
DC-DC Converter
Adjustable and Fixed 5V, 12V
FEATURES
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DESCRIPTIO
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Operates at Supply Voltages From 1.0V to 30V
Works in Step-Up or Step-Down Mode
Only Three External Off-the-Shelf 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 S8 Package
The LT1110 is a versatile micropower DC-DC converter.
The device requires only three external components to
deliver a fixed output of 5V or 12V. The very low minimum
supply voltage of 1.0V allows the use of the LT1110 in
applications where the primary power source is a single
cell. An on-chip auxiliary gain block can function as a low
battery detector or linear post regulator.
The 70kHz oscillator allows the use of surface mount
inductors and capacitors in many applications. Quiescent
current is just 300µA, making the device ideal in remote or
battery powered applications where current consumption
must be kept to a minimum.
The device can easily be configured as a step-up or
step-down converter, although for most step-down
applications or input sources greater than 3V, the LT1111
is recommended. Switch current limiting is user-adjustable
by adding a single external resistor. Unique reverse battery
protection circuitry limits reverse current to safe, non-
destructive levels at reverse supply voltages up to 1.6V.
APPLICATI
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Pagers
Cameras
Single-Cell to 5V Converters
Battery Backup Supplies
Laptop and Palmtop Computers
Cellular Telephones
Portable Instruments
Laser Diode Drivers
Hand-Held Inventory Computers
TYPICAL APPLICATI
All Surface Mount
Single Cell to 5V Converter
SUMIDA
CD54-470K
47µH
1
I
LIM
1.5V
AA CELL*
2
V
IN
SW1
90
MBRS120T3
5V
EFFICIENCY (%)
85
80
75
70
65
60
15µF
TANTALUM
55
50
0
LT1110 • TA01
3
V
IN
= 1.00V
LT1110-5
SENSE
8
SW2
4
GND
5
+
OPERATES WITH CELL VOLTAGE
≥
1.0V
*ADD 10
µ
F DECOUPLING CAPACITOR IF BATTERY
IS MORE THAN 2" AWAY FROM LT1110.
5
10
U
Efficiency
V
IN
= 1.50V
V
IN
= 1.25V
15
20
25
30
35
40
LOAD CURRENT (mA)
LT1110 • TA02
UO
UO
1
LINER [ LINEAR TECHNOLOGY ]
