Datasheet LTC3605 (Analog Devices)

LTC3605 15V, 5A Synchronous Step-Down Regulator
FeaTures DescripTion
n High Efficiency: Up to 96% The LTC®3605 is a high efficiency, monolithic synchronous n 5A Output Current buck regulator using a phase lockable controlled on-time n 4V to 15V VIN Range constant frequency, current mode architecture. PolyPhase n Integrated Power N-Channel MOSFETs operation allows multiple LTC3605 regulators to run out of (70mΩ Top and 35mΩ Bottom) phase while using minimal input and output capacitance. n Adjustable Frequency 800kHz to 4MHz The operating supply voltage range is from 15V down to n PolyPhase® Operation (Up to 12 Phases) 4V, making it suitable for dual lithium-ion battery inputs n Output Tracking as well as point of load power supply applications from n 0.6V ±1% Reference Accuracy a 12V or 5V rail. n Current Mode Operation for Excellent Line and Load The operating frequency is programmable from 800kHz to Transient Response 4MHz with an external resistor. The high frequency capa- n Shutdown Mode Draws Less Than 15µA Supply Current bility allows the use of small surface mount inductors. For n Available in 24-Pin (4mm × 4mm) QFN Package switching noise sensitive applications, it can be externally synchronized from 800kHz to 4MHz. The PHMODE pin allows user control of the phase of the outgoing clock
applicaTions
signal. The unique constant frequency/controlled on-time architecture is ideal for high step-down ratio applications n Point of Load Power Supply that are operating at high frequency while demanding n Portable Instruments fast transient response. Two internal phase-lock loops n Distributed Power Systems synchronize the internal oscillator to the external clock n Battery-Powered Equipment and also servos the regulator on-time to lock on to either the internal clock or the external clock if it’s present. L, LT, LTC, LTM, Linear Technology, Linear logo, PolyPhase and OPTI-LOOP are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5847554, 6580258, 6304066, 6476589, 6774611.
Typical applicaTion Efficiency and Power Loss High Efficiency 1MHz, 5A Step-Down Regulator
100 10 V V V IN = 12V OUT = 3.3V IN 90 f = 1MHz 4V TO 15V 22µF 80 ×2 PVIN SVIN POWER LOSS (W) CLKOUT INTV 70 CC V 1 OUT = 1.2V CLKIN 2.2µF 60 PGOOD BOOST 50 LTC3605 0.1µF 1µH SW VOUT 40 VOUT = 3.3V 3.3V EFFICIENCY (%) VOUT = 1.2V 0 VON 11.5k 30 47µF VIN RUN FB ×2 20 ITH 2.55k 10 RT 16k PGND 0 0.1 162k 10 100 1000 10000 220pF OUTPUT CURRENT (mA) 3605 TA01a 3605 TA01b 3605fh For more information www.linear.com/LTC3605 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Typical Applications Package Description Revision History Typical Application Related Parts