Features

• High Efficiency: Up to 95%
• Very Low Quiescent Current: Only 10μA During Operation
• 600mA Output Current at V_IN = 5V
• 2.65V to 10V Input Voltage Range
• 550kHz Constant-Frequency Operation
• No Schottky Diode Required
• Low Dropout Operation: 100% Duty Cycle
• Synchronizable from 400kHz to 700kHz
• Selectable Burst Mode® Operation or Pulse-Skipping Mode
• 0.8V Reference Allows Low Output Voltages
• Shutdown Mode Draws < 1μA Supply Current
• ±2% Output Voltage Accuracy
• Current Mode Control for Excellent Line and Load Transient Response
• Overcurrent and Overtemperature Protected
• Available in 8-Lead MSOP Package

Typical Application

Description

The LTC1877 s a high efficiency monolithic synchronous buck regulator using a constant-frequency, current mode architecture. Supply current during operation is only 10μA and drops to < 1μA in shutdown. The 2.65V to 10V input voltage range makes the LTC1877 ideally suited for both single and dual Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems.

Switching frequency is internally set at 550kHz, allowing the use of small surface mount inductors and capacitors. For noise sensitive applications the LTC1877 can be externally synchronized from 400kHz to 700kHz. 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.

The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.8V feedback reference voltage. The LTC1877 is available in a space saving 8-lead MSOP package. Lower input voltage applications (less than 7V abs max) should refer to the LTC1878 data sheet.