Datasheet LTC3605A (Analog Devices)

LTC3605A 20V, 5A Synchronous Step-Down Regulator
FeaTures DescripTion
n High Efficiency: Up to 96% The LTC®3605A is a high efficiency, monolithic synchro- n 5A Output Current nous buck regulator using a phase lockable controlled n 4V to 20V VIN Range on-time constant frequency, current mode architecture. n Integrated Power N-Channel MOSFETs PolyPhase operation allows multiple LTC3605A regula- (70mΩ Top and 35mΩ Bottom) tors to run out of phase while using minimal input and n Adjustable Frequency 800kHz to 4MHz output capacitance. The operating supply voltage range n PolyPhase® Operation (Up to 12 Phases) is from 20V down to 4V, making it suitable for dual, triple n Output Tracking or quadruple lithium-ion battery inputs as well as point n 0.6V ±1% Reference Accuracy of load power supply applications from 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 LTC3605: 15V Absolute Maximum VIN switching noise sensitive applications, it can be externally n LTC3605A: 22V Absolute Maximum VIN synchronized from 800kHz to 4MHz. The PHMODE pin n The LTC3605A Is Pin Compatible with the LTC3605 allows user control of the phase of the outgoing clock n Available in 24-Pin (4mm × 4mm) QFN Package signal. The unique constant frequency/controlled on-time architecture is ideal for high step-down ratio applications that are operating at high frequency while demanding
applicaTions
fast transient response. Two internal phase-lock loops synchronize the internal oscillator to the external clock n Point of Load Power Supply and also servos the regulator on-time to lock on to either n Portable Instruments the internal clock or the external clock if it’s present. n Distributed Power Systems L, LT, LTC, LTM, PolyPhase, OPTI-LOOP, Linear Technology and the Linear logo are registered n Battery-Powered Equipment 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 VOUT = 3.3V V 90 IN 4V TO 20V 22µF 80 ×2 PVIN SVIN POWER LOSS (W) 70 CLKOUT INTV 1 CC 60 CLKIN 2.2µF 50 PGOOD BOOST LTC3605A 0.1µF 1µH 40 SW VOUT EFFICIENCY (%) 3.3V 0.1 30 VON 11.5k 47µF V 20 IN RUN FB ×2 VIN = 8V ITH 2.55k 10 VIN = 12V RT VIN = 20V 16k 0 0.01 PGND 0.01 0.1 1 10 162k 220pF LOAD CURRENT (A) 3605A TA01a 3605A TA01b 3605afg For more information www.linear.com/LTC3605A 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Typical Applications Package Description Revision History Typical Application Related Parts