LTC3631 High Efficiency, High Voltage 100mA Synchronous Step-Down Converter FeaTuresDescripTion n Wide Input Voltage Range: Operation from 4.5V to 45V The LTC®3631 is a high voltage, high efficiency step-down n Overvoltage Lockout Provides Protection Up to 60V DC/DC converter with internal high side and synchronous n Internal High Side and Low Side Power Switches power switches that draws only 12μA typical DC supply n No Compensation Required current at no load while maintaining output voltage n 100mA Output Current regulation. n Low Dropout Operation: 100% Duty Cycle The LTC3631 can supply up to 100mA load current and n Low Quiescent Current: 12µA features a programmable peak current limit that provides n 0.8V ±1% Feedback Voltage Reference a simple method for optimizing efficiency in lower current n Adjustable Peak Current Limit applications. The LTC3631’s combination of Burst Mode® n Internal and External Soft-Start operation, integrated power switches, low quiescent cur- n Precise RUN Pin Threshold with Adjustable rent, and programmable peak current limit provides high Hysteresis efficiency over a broad range of load currents. n 3.3V, 5V and Adjustable Output Versions n Only Three External Components Required for Fixed With its wide 4.5V to 45V input range and internal overvolt- Output Versions age monitor capable of protecting the part from 60V surges, n Low Profile (0.75mm) 3mm × 3mm DFN and the LTC3631 is a robust converter suited for regulating a Thermally-Enhanced MS8E Packages wide variety of power sources. Additionally, the LTC3631 includes a precise run threshold and a soft-start feature applicaTions to guarantee that power system start-up is well-controlled in any environment. n 4mA to 20mA Current Loops n The LTC3631 is available in the thermally enhanced Industrial Control Supplies n 3mm × 3mm DFN and MS8E packages. Distributed Power Systems n Portable Instruments L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the n Battery-Operated Devices property of their respective owners. n Automotive Power Systems Typical applicaTionEfficiency and Power Loss vs Load Current 100 90 EFFICIENCY 1000 5V, 100mA Step-Down Converter 80 POWER LOSS (mW) 100µH V VOUT IN 70 100 VIN SW 5V TO 45V 5V 2.2µF LTC3631-5 10µF 100mA 60 RUN VOUT POWER LOSS HYST SS EFFICIENCY (%) 50 10 ISET GND 40 30 V 1 3631 TA01a IN = 12V VIN = 36V 200.1 1 10 100 LOAD CURRENT (mA) 3631 TA01b 3631fe For more information www.linear.com/LTC3631 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Related Parts