Features

• High Efficiency: Over 92% Possible
• Very Low Standby Current: 10µA Typ
• Available in Space Saving 8-Lead MSOP Package
• Internal 1.4ohms Power Switch (V_IN = 10V)
• Wide V_IN Range: 3V to 18V Operation
• Very Low Dropout Operation: 100% Duty Cycle
• Low-Battery Detector Functional During Shutdown
• Programmable Current Limit with Optional Current Sense Resistor (10mA to 400mA)
• Short-Circuit Protection
• Few External Components Required
• Active Low Micropower Shutdown: I_Q = 6µA Typ
• Pushbutton On/Off (LTC1475 Only)
• 3.3V, 5V and Adjustable Output Versions

Typical Application

Description

The LTC1474/LTC1475 series are high efficiency step-down converters with internal P-channel MOSFET power switches that draw only 10µA typical DC supply current at no load while maintaining output voltage. The LTC1474 uses logic-controlled shutdown while the LTC1475 features push button on/off.

The low supply current coupled with Burst Mode operation enables the LTC1474/LTC1475 to maintain high efficiency over a wide range of loads. These features, along with their capability of 100% duty cycle for low dropout and wide input supply range, make the LTC1474/LTC1475 ideal for moderate current (up to 300mA) battery-powered applications.

The peak switch current is user-programmable with an optional sense resistor (defaults to 325mA minimum if not used) providing a simple means for optimizing the design for lower current applications. The peak current control also provides short-circuit protection and excellent start-up behavior. A low-battery detector that remains functional in shutdown is provided .

The LTC1474/LTC1475 series availability in 8-lead MSOP and SO packages and need for few additional components provide for a minimum area solution.