Linear Technology introduced the LTC3605, a high efficiency, 4MHz synchronous buck regulator that uses a constant frequency controlled on-time, current mode architecture. The LTC3605 delivers up to 5A of continuous output current at output voltages as low as 0.6V with minimum thermal derating from a 4 x 4mm QFN package. It operates from an input voltage of 4 to 15V, making it well suited for dual-cell Li-Ion applications, as well as fixed rail systems with voltages up to 12V. The LTC3605’s switching frequency is user programmable from 800kHz to 4MHz, enabling the use of tiny capacitors and inductors.
The LTC3605 uses internal N-channel switches with RDS(ON)s of only 35mOhm and 70mOhm to deliver efficiencies as high as 96%. Its low minimum on-time allows low duty cycle operation at high switching frequencies. The LTC3605’s PolyPhase® operation (up to 12 phases) allows multiple regulators to be cascaded, running out of phase to minimize input and output capacitance. Current mode operation offers fast transient response while simplifying compensation. Additional features include output tracking and a shutdown current of only 15µA.
The LTC3605EUF is available in a 4 x 4mm QFN-24. Pricing starts at $4.25 each in 1,000-piece quantities and is available from stock.