ADP1109

a FEATURES Operates at Supply Voltages 2 V to 12 V Fixed 3.3 V, 5 V, 12 V and Adjustable Output Minimum External Components Required Ground Current: 320 ␮ A Oscillator Frequency: 120 kHz Logic Shutdown 8-Lead DIP and SO-8 Packages APPLICATIONS Cellular Telephones Single-Cell to 5 V Converters Laptop and Palmtop Computers Pagers Cameras Battery Backup Supplies Portable Instruments Laser Diode Drivers Hand-Held Inventory Computers Micropower Low Cost Fixed 3.3 V, 5 V, 12 V and Adjustable DC-to-DC Converter ADP1109 FUNCTIONAL BLOCK DIAGRAMS VIN SENSE R2 250k⍀ COMPARATOR 1.25V REFERENCE + A1 120kHz OSCILLATOR DRIVER ADP1109-3.3: R1 = 152k⍀ ADP1109-5: R1 = 83k⍀ ADP1109-12: R1 = 29k⍀ SW Q1 R1 GND SHUTDOWN Fixed Output VIN FB ADP1109 COMPARATOR 1.25V REFERENCE + A1 120kHz OSCILLATOR DRIVER Q1 SW GENERAL DESCRIPTION The ADP1109 is a versatile step-up switching regulator. The device requires only minimal external components to operate as a complete switching regulator. The ADP1109-5 can deliver 100 mA at 5 V from a 3 V input and the ADP1109-12 can deliver 60 mA at 12 V from a 5 V input. The device also features a logic controlled shutdown capability that, when a logic low is applied, will shut down the oscillator. The 120 kHz operating frequency allows for the use of small surface mount components. The gated oscillator capability eliminates the need for frequency compensation. VIN 5V GND SHUTDOWN Adjustable Output TYPICAL APPLICATION L1 33␮H D1 VIN SW SENSE + C1 22␮...