synchronous regulator in QFNLinear Technology’s LTC3604 high efficiency, 4 MHz synchronous buck regulator incorporates a unique constant frequency/controlled on-time, current mode architecture. It can deliver up to 2.5 A of continuous output current at output voltages as low as 0.6 V from a 3mm x 3 mm QFN or MSOP-16E package. Its current mode operation offers desirable line and load transient response even with high step-down ratios. The LTC3604 operates from an input voltage of 3.6 V to 15 V, making it appropriate for applications powered from dual-cell Li-Ion battery stacks as well as 5V and 12V intermediate bus systems. Its switching frequency is user programmable from 800kHz to 4MHz, enabling the use of tiny, low cost capacitors and inductors. The LTC3604 uses internal switches with RDS(ON) of 100 mOhms and 130 mOhms to provide efficiencies as high as 95 percent. Its control architecture enables it to achieve duty cycles as low as 5 percent while maintaining switching frequencies as high as 2.25MHz, making it ideal for high step-down ratio applications. Burst Mode operation is used to maximize light load efficiency, requiring only 300 µA (at no load).

Linear Technology Corp.