Features

• 1.5V to 5.5V Adjustable Output Voltage
• Synchronous Rectification: Up to 95% Efficiency
• 1A Switch Current (LTC3423) or
  2A Switch Current (LTC3424)
• Fixed Frequency Operation Up to 3MHz
• Wide Input Range: 0.5V to 5.5V (Operating)
• Very Low Quiescent Current: 38µA (Burst Mode’ Operation)
• No External Schottky Diode Required
• Synchronizable Switching Frequency
• Burst Mode Enable Control
• OPTI-LOOP™ Compensation
• Very Low Shutdown Current: <1µA
• Small 10-Pin MSOP Package

Typical Application

Description

The LTC3423 and LTC3424 are high efficiency, fixed frequency, step-up DC/DC converters that can regulate output voltages as low as 1.5V from a single cell. An applied voltage of at least 2.7V to the V_DD pin is required to power the internal control circuitry.

The devices include a 0.16 Ohms N-channel MOSFET switch and a 0.21 Ohms P-channel synchronous rectifier. The LTC3423 is intended for applications requiring less than 0.75W of output power and the LTC3424 for 1.5W or less. Switching frequencies up to 3MHz are programmed with an external timing resistor and the oscillator can be synchronized to an external clock.

Quiescent current is only 38µA in Burst Mode operation, maximizing battery life in portable applications. Burst Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin has either a clock or is driven low then the operation is at constant fixed frequency.

Other features include a 1µA shutdown, thermal shutdown and current limit. The LTC3423 and LTC3424 are available in the 10-lead MSOP package. For applications requiring an output voltage greater than 2.6V, the LTC3401 and LTC3402 are recommended without the need of a separate voltage for the V_DD pin.