Lt1073 Micropower Dc/Dc

LT1073 Micropower DC/DC Converter Adjustable and Fixed 5V, 12V

FEATURES
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DESCRIPTIO

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No Design Required Operates at Supply Voltages from 1V to 30V Consumes Only 95µA Supply Current 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 SwitchFixed or Adjustable Output Voltage Versions Space-Saving 8-Pin PDIP or SO-8 Package

The LT®1073 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 1V allows the use of the LT1073 in applications where the primary power source is a single cell. An on-chip auxiliary gain blockcan function as a lowbattery detector or linear post-regulator. Average current drain of the LT1073-5 used as shown in the Typical Application circuit below is just 135µA unloaded, making it ideal for applications where long battery life is important. The circuit shown can deliver 5V at 40mA from an input as low as 1.25V and 5V at 10mA from a 1V input. The device can easily be configured as astep-up or stepdown converter, although for most step-down applications or input sources greater than 3V, the LT1173 is recommended. Switch current limiting is user-adjustable by adding a single external resistor. Unique reversebattery protection circuitry limits reverse current to safe, nondestructive levels at reverse supply voltages up to 1.6V.
, LTC and LT are registered trademarks of LinearTechnology Corporation.

APPLICATIO S
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Pagers Cameras Single-Cell to 5V Converters Battery Backup Supplies Laptop and Palmtop Computers Cellular Telephones Portable Instruments 4mA to 20mA Loop Powered Instruments Hand-Held Inventory Computers Battery-Powered α, β, and γ Particle Detectors

TYPICAL APPLICATION
Single-Cell to 5V Converter
CONTINUOUS OPERATION (HOURS)CADDELL-BURNS 7300-12 1N5818 82µH

Single Alkaline “AA” Cell Operating Hours vs DC Load Current
1000
5V 40mA

1 ILIM 1.5V AA CELL*

2 VIN SW1 3

100

LT1073-5 SENSE GND 5 SW2 4 8

10

+

100µF SANYO 0S-CON

1
OPERATES WITH CELL VOLTAGE ≥1V *ADD 10µF DECOUPLING CAPACITOR IF BATTERY IS MORE THAN 2" AWAY FROM LT1073

1
1073 TA01

U
L = 180µH L = 82µH 10 LOAD CURRENT (mA) 100LT1073 TA02

U

U

1

LT1073

ABSOLUTE
(Note 1)

AXI U RATI GS

PACKAGE/ORDER I FOR ATIO
TOP VIEW ILIM 1 VIN 2 SW1 3 SW2 4 N8 PACKAGE 8-LEAD PDIP 8 7 6 5 FB (SENSE)* SET A0 GND

Supply Voltage, Step-Up Mode ................................ 15V Supply Voltage, Step-Down Mode ........................... 36V SW1 Pin Voltage ......................................................50V SW2 Pin Voltage ........................................... –0.4 to VIN Feedback Pin Voltage (LT1073) ................................. 5V Switch Current ........................................................ 1.5A Maximum Power Dissipation ............................. 500mW Operating Temperature Range ..................... 0°C to 70°C Storage Temperature Range ................. – 65°C to150°C Lead Temperature (Soldering, 10 sec).................. 300°C

S8 PACKAGE 8-LEAD PLASTIC SO

*FIXED VERSIONS

TJMAX = 125°C, θJA = 100°C/W (N8) TJMAX = 125°C, θJA = 120°C/W (S8)

ORDER PART NUMBER LT1073CN8 LT1073CN8-5 LT1073CN8-12 LT1073CS8 LT1073CS8-5 LT1073CS8-12 S8 PART MARKING 1073 10735 107312

Consult factory for parts specified with wider operating temperature ranges.

Theq denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 1.5V unless otherwise specified.
SYMBOL IQ IQ VIN PARAMETER Quiescent Current Quiescent Current, Step-Up Mode Configuration Input Voltage CONDITIONS Switch Off No Load Step-Up Mode Step-Down Mode Comparator Trip Point Voltage VOUT Output Sense Voltage Comparator...