POWER LOSS (mW) LTC3859AL Triple Output, Buck/Buck/Boost Synchronous Controller with 28A Burst Mode I Q FEATURES DESCRIPTION n Low Operating I : 28A (One Channel On) The LTC 3859AL is a high performance triple output (buck/ Q n Dual Buck Plus Single Boost Synchronous Controllers buck/boost) synchronous DC/DC switching regulator n controller that drives all N-channel power MOSFET stages. Outputs Remain in Regulation Through Cold Crank Constant frequency current mode architecture allows Down to 2.5V a phase-lockable switching frequency of up to 850kHz. n Wide Bias Input Voltage Range: 4.5V to 38V The LTC3859AL operates from a wide 4.5V to 38V input n Buck Output Voltage Range: 0.8V V 24V OUT supply range. When biased from the output of the boost n Boost Output Voltage Up to 60V converter or another auxiliary supply, the LTC3859AL can n R or DCR Current Sensing SENSE operate from an input supply as low as 2.5V after start-up. n 100% Duty Cycle for Boost Synchronous MOSFET Even in Burst Mode Operation The 28A no-load quiescent current extends operating n runtime in battery powered systems. OPTI-LOOP com- Phase-Lockable Frequency (75kHz to 850kHz) n pensation allows the transient response to be optimized Programmable Fixed Frequency (50kHz to 900kHz) over a wide range of output capacitance and ESR values. n Selectable Continuous, Pulse-Skipping or Low Ripple The LTC3859AL features a precision 0.8V reference for Burst Mode Operation at Light Loads the bucks, 1.2V reference for the boost and a power good n Very Low Buck Dropout Operation: 99% Duty Cycle output indicator. The PLLIN/MODE pin selects among n Adjustable Output Voltage Soft-Start or Tracking Burst Mode operation, pulse-skipping mode, or continu- n Low Shutdown I : 10A Q ous inductor current mode at light loads. n Small 38-Lead 5mm 7mm QFN and TSSOP Packages Compared to the LTC3859 and the LTC3859A, the APPLICATIONS LTC3859AL is fully pin-compatible, but with lower Burst n Mode operation I (28A with one channel on). Automotive Always-On and Start-Stop Systems Q n All registered trademarks and trademarks are the property of their respective owners. Protected Battery Operated Digital Devices by U.S. Patents including 5481178, 5705919, 5929620, 6144194, 6177787, 6580258. n Distributed DC Power Systems n Multioutput Buck-Boost Applications TYPICAL APPLICATION V OUT3 REGULATED AT 10V WHEN V < 10V IN 220F 1F Efficiency and Power Loss vs FOLLOWS V WHEN V > 10V IN IN 499k V Output Current BIAS V FB3 TG1 68.1k 100 10000 V = 12V IN 4.9H V 6m OUT1 90 SW1 5V TG3 1.2H V 2m V = BURST IN OUT1 5A 80 1000 2.5V TO 38V EFFICIENCY SW3 BG1 LTC3859AL (START-UP ABOVE 5V) 70 220F BG3 60 100 + SENSE1 50 SENSE1 SENSE3 + V SENSE3 40 10 FB1 357k INTV CC 68.1k 220F 30 RUN1, 2, 3 V = BURST LOSS 4.7F OUT1 20 1 EXTV BOOST1, 2, 3 V CC OUT1 0.1F 10 SW1, 2, 3 TG2 6.5H V 8m OUT2 0 0.1 SW2 8.5V 0.0001 0.001 0.01 0.1 1 10 I TH1, 2, 3 3A BG2 OUTPUT CURRENT (A) 3859al TA01b SENSE2+ SENSE2 TRACK/SS1, 2 0.1F V SS3 FB2 649k PGND SGND 68.1k 68F 3859al TA01a Rev. B 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC3859AL ABSOLUTE MAXIMUM RATINGS (Note 1) + + Bias Input Supply Voltage (V ) .............. 0.3V to 40V SENSE1 , SENSE2 , SENSE1 BIAS Buck Top Side Driver Voltages SENSE2 Voltages ..................................... 0.3V to 28V + (BOOST1, BOOST2) ............................. 0.3V to 46V SENSE3 , SENSE3 Voltages ..................... 0.3V to 40V Boost Top Side Driver Voltages FREQ Voltages ......................................0.3V to INTV CC (BOOST3) ............................................ 0.3V to 76V EXTV ...................................................... 0.3V to 14V CC Buck Switch Voltage (SW1, SW2) ................ 5V to 40V I , I , I , V , V , V Voltages .... 0.3V to 6V TH1 TH2 TH3 FB1 FB2 FB3 Boost Switch Voltage (SW3) ........................ 5V to 70V PLLIN/MODE, PGOOD1, OV3 Voltages ........ 0.3V to 6V INTV , (BOOST1SW1), TRACK/SS1, TRACK/SS2, SS3 Voltages ..... 0.3V to 6V CC (BOOST2SW2), (BOOST3SW3) ........... 0.3V to 6V Operating Junction Temperature Range (Notes 2, 3) RUN1, RUN2, RUN3 .................................... 0.3V to 8V LTC3859ALE, LTC3859ALI ................ 40C to 125C Maximum Current Sourced Into Pin LTC3859ALH ..................................... 40C to 150C from Source >8V ..............................................100A LTC3859ALMP ................................... 55C to 150C Storage Temperature Range .............. 65C to 150C PIN CONFIGURATION TOP VIEW TOP VIEW 1 38 TRACK/SS1 I TH1 2 37 PGOOD1 V FB1 + 3 36 TG1 SENSE1 38 37 36 35 34 33 32 4 35 SW1 SENSE1 FREQ 1 31 SW1 5 34 BOOST1 FREQ PLLIN/MODE 2 30 BOOST1 6 33 BG1 PLLIN/MODE SS3 3 29 BG1 7 32 SW3 SS3 + SENSE3 4 28 SW3 + 8 31 TG3 SENSE3 SENSE3 5 27 TG3 9 30 BOOST3 SENSE3 V BOOST3 6 26 FB3 39 39 10 29 BG3 V FB3 PGND PGND I 7 25 BG3 TH3 11 28 V I TH3 BIAS SGND 8 24 V BIAS 12 27 EXTV SGND CC RUN1 9 23 EXTV CC 13 26 INTV RUN1 CC RUN2 10 22 INTV CC 14 25 BG2 RUN2 RUN3 21 BG2 11 15 24 BOOST2 RUN3 20 SENSE2 12 BOOST2 16 23 SW2 SENSE2 13 14 15 16 17 18 19 + 17 22 TG2 SENSE2 18 21 OV3 V FB2 19 20 TRACK/SS2 I TH2 UHF PACKAGE FE PACKAGE 38-LEAD (5mm 7mm) PLASTIC QFN 38-LEAD PLASTIC TSSOP T = 150C, q = 34.7C/W JMAX JA T = 150C, q = 25C/W JMAX JA EXPOSED PAD (PIN 39) IS PGND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 39) IS PGND, MUST BE SOLDERED TO PCB Rev. B 2 For more information www.analog.com + SENSE2 SENSE1 + V SENSE1 FB2 I V TH2 FB1 TRACK/SS2 I TH1 OV3 TRACK/SS1 TG2 PGOOD1 SW2 TG1