LT1110_15 Datasheet, PDF (1/16 Pages) Linear Technology – Micropower DC-DC Converter Adjustable and Fixed 5V, 12V

FEATURES
s _{Operates at Supply Voltages From 1.0V to 30V}
s _{Works in Step-Up or Step-Down Mode}
s _{Only Three External Off-the-Shelf 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 S8 Package}
APPLICATI S
s _Pagers
s _Cameras
s _{Single-Cell to 5V Converters}
s _{Battery Backup Supplies}
s _{Laptop and Palmtop Computers}
s _{Cellular Telephones}
s _{Portable Instruments}
s _{Laser Diode Drivers}
s _{Hand-Held Inventory Computers}
LT1110
Micropower
DC-DC Converter
Adjustable and Fixed 5V, 12V
DESCRIPTIO
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.
TYPICAL APPLICATI
All Surface Mount
Single Cell to 5V Converter
SUMIDA
CD54-470K
47µH
MBRS120T3
1
2
1.5V
AA CELL*
I_LIM
V _IN
SW1
3
LT1110-5
SENSE
GND
SW2 ⁸
+
5
4
5V
15µF
TANTALUM
OPERATES WITH CELL VOLTAGE ≥ 1.0V
*ADD 10µF DECOUPLING CAPACITOR IF BATTERY
IS MORE THAN 2" AWAY FROM LT1110.
LT1110 • TA01
Efficiency
90
85
80
V_IN = 1.50V
75
V_IN = 1.25V
70
V_IN = 1.00V
65
60
55
50
0 5 10 15 20 25 30 35 40
LOAD CURRENT (mA)
LT1110 • TA02
1