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LTC3612 - 3A, 4MHz Monolithic Synchronous Step-Down DC/DC Converter

The LTC®3612 is a low quiescent current monolithic synchronous buck regulator using a current mode, constant frequency architecture. The no-load DC supply current in sleep mode is only 70μA while maintaining the output voltage (Burst Mode operation) at no load, dropping to zero current in shutdown. The 2.25V to 5.5V input supply voltage range makes the LTC3612 ideally suited for single Li-Ion as well as fixed low voltage input applications. 100% duty cycle capability provides low dropout operation, extending the operating time in battery-powered systems.

The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. For switching noise-sensitive applications, the LTC3612 can be synchronized to an external clock at up to 4MHz.

Forced continuous mode operation in the LTC3612 reduces noise and RF interference. Adjustable compensation allows the transient response to be optimized over a wide range of loads and output capacitors.

The internal synchronous switch increases efficiency and eliminates the need for an external catch diode, saving external components and board space. The LTC3612 is offered in a leadless 20-pin 3mm × 4mm QFN or a thermally enhanced 20-pin TSSOP package.

Features 3A Output Current 2.25V to 5.5V Input Voltage Range Low Output Ripple Burst Mode® Operation: IQ = 70μA ±1% Output Voltage Accuracy Output Voltage Down to 0.6V High Efficiency: Up to 95% Low Dropout Operation: 100% Duty Cycle Shutdown Current: ≤1μA Adjustable Switching Frequency: Up to 4MHz Optional Active Voltage Positioning (AVP) with Internal Compensation Selectable Pulse-Skipping/Forced Continuous/Burst Mode Operation with Adjustable Burst Clamp Programmable Soft-Start Inputs for Start-Up Tracking or External Reference DDR Memory Mode, IOUT = ±1.5A Available in Thermally Enhanced 20-Pin (3mm × 4mm) QFN and TSSOP Packages Typical Application

Applications Point-of-Load Supplies Distributed Power Supplies Portable Computer Systems DDR Memory Termination Handheld Devices Packaging

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