Features

• 600mA Output Current (V_IN >/= 4V)
• High Efficiency: Up to 96%
• Constant Frequency: 350kHz Synchronizable to 550kHz
• 2.85V to 8.5V V_IN Range
• 0.8V Feedback Reference Allows Low Voltage Outputs: 0.8V <= V_OUT <= V_IN
• No Schottky Diode Required
• 1.19V ±1% Reference Output Pin
• Selectable Burst Mode™ Operation/Pulse Skipping Mode
• Low Dropout Operation: 100% Duty Cycle
• Precision 2.7V Undervoltage Lockout
• Current Mode Control for Excellent Line and Load Transient Response
• Low Quiescent Current: 200µA
• Shutdown Mode Draws Only 11µA Supply Current
• Available in 8-Lead SO Package

Typical Application

Description

The LTC1707 is a high efficiency monolithic current mode synchronous buck regulator using a fixed frequency architecture. The operating supply range is from 8.5V down to 2.85V, making it suitable for both single and dual lithium-ion battery-powered applications. Burst Mode operation provides high efficiency at low load currents. 100% duty cycle provides low dropout operation, extending operating time in battery-powered systems.

The switching frequency is internally set at 350kHz, allowing the use of small surface mount inductors. For noise sensitive applications it can be externally synchronized up to 550kHz. Burst Mode operation is inhibited during synchronization or when the SYNC/MODE pin is pulled low preventing low frequency ripple from interfering with audio circuitry. Soft-start is provided by an external capacitor.

The internal synchronous MOSFET switch increases efficiency and eliminates the need for an external Schottky diode, saving components and board space. Low output voltages down to 0.8V are easily achieved due to the 0.8V internal reference. The LTC1707 comes in an 8-lead SO package.