POWER LOSS (mW) LTC3609 32V, 6A Monolithic Synchronous Step-Down DC/DC Converter Fae Tseru Dpircse Tnoi n 6A Output Current The LTC 3609 is a high efcfi iency, monolithic synchronous n Wide V Range = 4V to32V (36V Maximum) step-down DC/DC converter that can deliver up to 6A output IN n InternalN-Channel MOSFETs current from a 4V to 32V (36V maximum) input supply. It n True CurrentMode Control uses a valley current control architecture to deliver very n Optimized for High Step-Down Ratios low duty cycle operation at high frequency with excellent n t 100ns transient response. The operating frequency is selected ON(MIN) n Extremely Fast Transient Response by an external resistor and is compensated for variations n Stable with CeramicC in V and V . OUT IN OUT n 1% 0.6V VoltageReference The LTC3609 can be configured for discontinuous or n Power Good Output Voltage Monitor forced continuous operation at light load. Forced continu- n Adjustable On-Time/Switching Frequency ous operation reduces noise and RF interference while n Adjustable Current Limit discontinuous mode provides high efficiency by reducing n Programmable Soft-Start switching losses at light loads. n Output Overvoltage Protection n Fault protection is provided by internal foldback current Optional Short-Circuit Shutdown Timer n limiting, an output overvoltage comparator and an optional Low Shutdown I : 15A Q n short-circuit shutdown timer. Soft-start capability for sup- Available in a 7mm 8mm 52-Pin QFN Package ply sequencing is accomplished using an external timing a acilpp Tsnoi capacitor. The regulator current limit is user programmable. A power good output voltage monitor indicates when n Point of Load Regulation the output is in regulation. The LTC3609 is available in a n Distributed Power Systems compact 7mm 8mm QFN package. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 6100678, 6580258, 5847554, 6304066. T lacipy a acilpp Tnoi Efficiency and Power Loss HighEfficiency Step-Down Converter vs Load Current 187k V V I 100 10000 0.1F OUT ON ON V EFFICIENCY IN 90 RUN/SS V IN 4V TO 32V 10F 80 100pF x3 1000 LTC3609 70 1.2H V OUT SW 2.5V 60 1000pF 6A 0.22F 100F 50 100 I BOOST x2 POWER LOSS TH 15.8k 40 30 SGND INTV CC 30.1k 10 20 FCB V = 12V V = 2.5V 10 OUT IN 4.7F V RNG EXTV = 5V V = 25V IN CC PGND 0 1 PGOOD 0.01 0.1 1 10 EXTV V CC FB LOAD CURRENT (A) 3609 TA01b 9.53k 3609 TA01a 3609fb EFFICIENCY (%)LTC3609 a ulosb T e Mixa Mu M r a Tsgni p ni c no Farugi Tnoi (Note1) TOP VIEW Input Supply Voltage (SV , PV , I ) ....... 36V to 0.3V IN IN ON Boosted Topside Driver Supply Voltage (BOOST) ................................................ 42V to 0.3V SW Voltage ............................................ 36V to 0.3V PV 1 40 PGND IN INTV , EXTV , (BOOST SW), RUN/SS, PV 2 39 PGND CC CC IN PV 3 38 PGND IN PGOOD Voltages ...................................... 7V to 0.3V 53 PV 4 37 PGND IN PV 55 FCB, V , V Voltages ............ INTV + 0.3V to 0.3V IN ON RNG CC SW PV 5 36 PGND IN I , V Voltages ....................................... 2.7V to 0.3V TH FB PV 6 35 PGND IN Operating Junction Temperature Range PV 7 34 PGND IN SW 8 33 SW (Notes 2, 4) ........................................ 40C to 125C NC 9 32 INTV CC Storage Temperature Range ................... 55C to 125C SGND 10 31 INTV CC BOOST 11 30 SV IN 54 RUN/SS 12 29 EXTV SGND CC V 13 28 NC ON SGND 14 27 SGND WKG PACKAGE 52-LEAD (7mm 8mm) QFN MULTIPADs T = 125C, = 29C/W JMAX JA ro D re ni Fro Ma Tnoi LEAD FREE FINISH TAPE AND REEL PARTMARKING* PACKAGE DESCRIPTION TEMPERATURERANGE LTC3609EWKG PBF LTC3609EWKG TRPBF LTC3609WKG 40C to 125C 52-Lead (7mm 8mm) Plastic QFN LTC3609IWKG PBF LTC3609IWKG TRPBF LTC3609WKG 40C to 125C 52-Lead (7mm 8mm) Plastic QFN Consult LTC Marketing for parts speciefi d with wider operating temperature ranges. *The temperature grade is identiefi d by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: