The LTC3604 is a high efficiency, 4MHz synchronous buck regulator that incorporates a unique constant frequency/controlled on-time, current mode architecture. It can deliver up to 2.5A of continuous output current at output voltages as low as 0.6V from a 3mm x 3mm QFN or MSOP-16E package. Its current mode operation offers excellent line and load transient response even with high step-down ratios. The LTC3604 operates from an input voltage of 3.6V to 15V, making it ideal 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 only 100mOhms and 130mOhms to deliver efficiencies as high as 95%. Its unique control architecture enables it to achieve duty cycles as low as 5% while maintaining switching frequencies as high as 2.25MHz, making it ideal for high step-down ratio applications, such as 12VIN to 1.2VOUT conversions. Burst Mode® operation is used to maximize light load efficiency, requiring only 300µA (at no load) and making the LTC3604 well suited for applications demanding maximum battery run time. For applications requiring the lowest possible noise, the LTC3604 can be configured to run in forced continuous mode, for minimum noise and potential RF interference. Additional features include a power good voltage monitor, output voltage tracking capability, and short circuit protection.