The MC34280 power IC provides two boost regulator outputs and some power management supervisory functions. The regulator uses pulse frequency modulation (PFM). The main boost regulator output is externally adjustable from 2.7V to 5V. An internal synchronous rectifier is used to ensure high efficiency (up to 87%). A configurable power transistor built into the auxiliary regulator produces a wide range of positive voltages (which can be used for LCD contrast voltages). This voltage can be adjusted by an external potentiometer from +5 V to +25 V; or by a microprocessor, digitized, through a 6-bit internal DAC. The MC34280 is designed for battery powered handheld products. With a low start-up voltage from 1V and low quiescent current (35mA typical) the MC34280 is best suited for operation on 12 AA/AAA batteries. In addition, supervisory functions, such as low battery detection, CPU power-on reset, and backup battery control, are also included on the chip. It makes the MC34280 the best single-chip power management solution for applications such as electronic organizers and PDAs.

Features:
• Low input voltage, 1V register • Low quiescent current in standby mode: 35mA typical • PFM and synchronous rectification to ensure high efficiency (87% @ 200mA load)
• Adjustable main output: nominal 3.3V @ 200mA max, with 1.8V input • Auxiliary output voltage can be digitally controlled by microprocessor • Auxiliary output voltage: +5 V max @ 25mA with 1.8V input + 25 V @ 15mA max with 1.8V, input • Current limit protection • Programmable delay on power-on reset signal • Low battery detection • Lithium battery backup • 32-pin LQFP package

application:
• Digital organizer and dictionary • Personal Digital Assistant (PDA) • Dual output power supply (for microcontrollers, logic, memory, LCD)
• Handheld battery powered device (1-2 AA/AAA batteries)