Features

• 3.6V to 15V Input Voltage Range
• 3A Output Current per Channel
• Up to 95% Efficiency
• Low Duty Cycle Operation: 5% at 2.25MHz
• Selectable 0°/180° Phase Shift Between Channels
• Adjustable Switching Frequency: 500kHz to 4MHz
• External Frequency Synchronization
• Current Mode Operation for Excellent Line and Load Transient Response
• 0.6V Reference Allows Low Output Voltages
• User Selectable Burst Mode® Operation or Forced Continuous Operation
• Output Voltage Tracking and Soft-Start Capability
• Short-Circuit Protected
• Overvoltage Input and Overtemperature Protection
• Low Power 2.5V Linear Regulator Output
• Power Good Status Outputs
• Available in (4mm × 5mm) QFN-28 and 28-Lead TSSOP Packages

Typical Application

Description

The LTC®3633 is a high efficiency, dual-channel monolithic synchronous buck regulator using a controlled on-time, current mode architecture, with phase lockable switching frequency. The two channels can run 180° out of phase, which relaxes the requirements for input and output capacitance. The operating supply voltage range is from 3.6V to 15V, making it suitable for dual cell lithium-ion batteries as well as point of load power supply applications from a 12V or 5V supply.

The operating frequency is programmable and synchronizable from 500kHz to 4MHz with an external resistor. The high frequency capability allows the use of small surface mount inductors and capacitors. The unique constant frequency/controlled on-time architecture is ideal for high step-down ratio applications that operate at high frequency while demanding fast transient response. An internal phase lock loop servos the on-time of the internal one-shot timer to match the frequency of the internal clock or an applied external clock.

The LTC3633 can select between forced continuous mode and high efficiency Burst Mode operation.