LTC3864 60V Low IQ Step-Down DC/DC Controller with 100% Duty Cycle Capability FeaTuresDescripTion n Wide Operating VIN Range: 3.5V to 60V The LTC®3864 is a robust, high voltage step-down DC/DC n Wide VOUT Range: 0.8V to VIN controller optimized for automotive and industrial applica- n Low Operating IQ = 40µA tions. It drives a P-channel power MOSFET switch allowing n Very Low Dropout Operation: 100% Duty Cycle 100% duty cycle operation. The wide input and output volt- n Strong High Voltage MOSFET Gate Driver age ranges cover a multitude of applications. This device n Constant Frequency Current Mode Architecture has been verified with the failure mode and effects analysis n Verified FMEA for Adjacent Pin Open/Short (FMEA) procedure for operation during failure conditions. n Selectable High Efficiency Burst Mode® Operation or Pulse-Skipping Mode at Light Loads The LTC3864 offers excellent light load efficiency, draw- n Programmable Fixed Frequency: 50kHz to 850kHz ing only 40µA quiescent current in a user programmable n Phase-Lockable Frequency: 75kHz to 750kHz Burst Mode operation. Its peak current mode, constant n Accurate Current Limit frequency PWM architecture provides for good control of n Programmable Soft-Start or Voltage Tracking switching frequency and output current limit. The switch- n Internal Soft-Start Guarantees Smooth Start-Up ing frequency can be programmed from 50kHz to 850kHz n Power Good Output Voltage Monitor with an external resistor and can be synchronized to an n Low Shutdown I external clock from 75kHz to 750kHz. Q = 7µA n Available in Small 12-Pin Thermally Enhanced MSOP The LTC3864 offers programmable soft-start or output and DFN Packages tracking. Safety features include overvoltage protection, overcurrent and short-circuit protection including fre- applicaTions quency foldback and a power good output signal. n Industrial and Automotive Power Supplies The LTC3864 is available in thermally enhanced 12-Pin n Telecom Power Supplies MSOP and 3mm × 4mm DFN packages. n Distributed Power Systems L, LT, LTC, LTM, OPTI-LOOP, Linear Technology, Burst Mode and the Linear logo are registered trademarks and Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5731694. Typical applicaTion5.2V to 60V Input, 5V/2A Output, 350kHz Step-Down ConverterEfficiency VIN* 100 5.2V TO 60V 0.47µF 10µF Burst Mode OPERATION CAP 90 RUN V 350kHz IN 25mΩ PLLIN/MODE 80 SS SENSE PULSE-SKIPPING LTC3864 3.3nF GATE 9.09k 10µH 70 ITH VOUT* EFFICIENCY (%) 5V 2A FREQ 60 100k 422k 47µF V SGND ×2 IN = 12V VOUT = 5V PGOOD 500.01 0.1 1 PGND VFB LOAD CURRENT (A) *V 80.6k OUT FOLLOWS VIN 3864 TA01b WHEN 3.5V ≤ VIN ≤ 5.2V 3864 TA01a 3864fa For more information www.linear.com/LTC3864 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
