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