MC34280FTBR2

• Low Input Voltage, 1V up
• 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: +5V @ 25mA max, with 1.8V input +25V @ 15mA max, with 1.8V input
• Current Limit Protection
• PowerON Reset Signal with Programmable Delay
• Battery Low Detection
• Lithium Battery Backup
• 32Pin LQFP Package

• Digital Organizer and Dictionary
• Personal Digital Assistance (PDA)
• Dual Output Power Supply (For MPU, Logic, Memory, LCD)
• Handheld Battery Powered Device (12 AA/AAA cell)

The MC34280 is a power supply integrated circuit which provides two boost regulated outputs and some power management supervisory functions. Both regulators apply PulseFrequencyModulation (PFM). The main stepup regulator output can be externally adjusted from 2.7V to 5V. An internal synchronous rectifier of MC34280 is used to ensure high efficiency (achieve 87%). The auxiliary regulator with a builtin power transistor can be configured to produce a wide range of positive voltage (can be used for LCD contrast voltage). This voltage of MC34280 can be adjusted from +5V to +25V by an external potentiometer; or by a microprocessor, digitally through a 6bit internal DAC.

The MC34280 has been designed for battery powered handheld products. With the low startup voltage from 1V and the low quiescent current (typical 35 mA); the MC34280 is best suited to operate from 1 to 2 AA/ AAA cell. Moreover, supervisory functions such as low battery detection, CPU poweron reset, and backup battery control, are also included in the chip. It makes the MC34280 the best onechip power management solution for applications such as electronic organizers and PDAs.