POWER LOSS (W) LTC3605A 20V, 5A Synchronous Step-Down Regulator Fea T Descrip T 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 V Range on-time constant frequency, current mode architecture. IN n Integrated Power N-Channel MOSFETs PolyPhase operation allows multiple LTC3605A regula- (70m Top and 35m 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 15A Supply Current bility allows the use of small surface mount inductors. For n LTC3605: 15V Absolute Maximum V IN switching noise sensitive applications, it can be externally n LTC3605A: 22V Absolute Maximum V IN 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 fast transient response. Two internal phase-lock loops a T 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 its 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 a T Efficiency and Power Loss High Efficiency 1MHz, 5A Step-Down Regulator 100 10 V = 3.3V OUT 90 V IN 4V TO 20V 80 22F 2 PV SV IN IN 70 1 CLKOUT INTV CC 60 2.2F CLKIN 50 BOOST PGOOD 0.1F 1H LTC3605A 40 V OUT SW 0.1 3.3V 30 V 11.5k ON 47F 20 V RUN FB IN V = 8V IN 2 V = 12V 10 IN ITH 2.55k V = 20V RT IN 0 0.01 16k PGND 0.01 0.1 1 10 162k 220pF LOAD CURRENT (A) 3605A TA01b 3605A TA01a 3605afg 1 For more information www.linear.com/LTC3605A EFFICIENCY (%) ion pplica ions pplica ion uresLTC3605A a Te Maxi Mu M r a T p in c F T (Note 1) TOP VIEW PV , SV , SW Voltage.............................. 0.3V to 22V IN IN SW Transient Voltage ..................................2V to 24.5V BOOST Voltage ..........................0.3V to PV + INTV IN CC 24 23 22 21 20 19 RUN Voltage............................................... 0.3V to 22V RT 1 18 PV IN V Voltage ............................................... 0.3V to SV ON IN PHMODE 2 17 PV IN INTV Voltage ......................................... 0.3V to 3.6V MODE 3 16 SW CC 25 PGND FB 4 15 SW ITH, RT, CLKOUT, PGOOD Voltage ........0.3V to INTV CC TRACK/SS 5 14 SW CLKIN, PHMODE, MODE Voltage ..........0.3V to INTV CC ITH 6 13 SW TRACK/SS, FB Voltage ..........................0.3V to INTV CC 7 8 9 10 11 12 Operating Junction Temperature Range (Note 2) .................................................. 40C to 125C Storage Temperature Range .................. 65C to 125C UF PACKAGE 24-LEAD (4mm 4mm) PLASTIC QFN T = 125C, = 37C/W JMAX JA EXPOSED PAD (PIN 25) IS PGND, MUST BE SOLDERED TO PCB o r Der i n F Ma T