LTC7817 40V, Low I , 3MHz, Q Triple Output Buck/Buck/Boost Synchronous Controller FEATURES DESCRIPTION n Dual Buck Plus Single Boost Synchronous Controllers The LTC 7817 is a high performance triple output (buck/ n Low Operating I : buck/boost) synchronous DC/DC switching regulator con- Q 14A (14V to 3.3V, Channel 1 On) troller that drives all N-channel power MOSFET stages. n Outputs Remain in Regulation Through Cold Crank Its constant frequency current mode architecture allows Down to 1V Input Supply Voltage a phase-lockable switching frequency of up to 3MHz. n Wide Bias Input Voltage Range: 4.5V to 40V The LTC7817 operates from a wide 4.5V to 40V input n Buck and Boost Output Voltages up to 40V supply range. When biased from the output of the boost n R or DCR Current Sensing SENSE converter or another auxiliary supply, the LTC7817 can n PassThru Operation: 100% Duty Cycle for operate from an input supply as low as 1V after start-up. Boost Synchronous MOSFET The very low no-load quiescent current extends operating n Programmable Fixed Frequency (100kHz to 3MHz) run time in battery powered systems. OPTI-LOOP com- n Phase-Lockable Frequency (100kHz to 3MHz) pensation allows the transient response to be optimized n Selectable Continuous, Pulse-Skipping, or Low over a wide range of output capacitance and ESR values. Ripple Burst Mode Operation at Light Loads The LTC7817 features a precision 0.8V reference for the n Very Low Buck Dropout Operation: 99% Duty Cycle bucks, 1.2V reference for the boost and a power good n Low Shutdown I : 1.5A Q output indicator. n Small 38-Lead 5mm 7mm QFN Package n AEC-Q100 Qualified for Automotive Applications The LTC7817 synchronous boost PassThru capability minimizes losses in automotive start-stop applications. APPLICATIONS All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6144194, 6177787, 6580258. n Automotive and Transportation n Industrial n Military/Avionics TYPICAL APPLICATION V OUT3 REGULATED TO 10V VBIAS WHEN V < 10V IN 22F V 150F FB3 FOLLOWS V LTC7817 Response to a Cold IN TG3 TG1 WHEN V > 10V LTC7818 Response to a Cold Crank IN Crank Automotive Waveform BOOST3 BOOST1 Automotive Waveform 1.4H 0.9H 1.5m V 0.1F 0.1F 2m OUT1 3.3V V SW3 IN SW1 22F 12A 1V TO 38V 330F STARTUP BG3 V BG1 BATT ABOVE 5V 150F V LTC7817 OUT3 210k SENSE3 SENSE1+ + SENSE3 SENSE1 VOLTAGE V FB1 V RUN1,2,3 OUT3 2V/DIV V OUT3 I 68.1k TH1,2,3 V OUT2 TRACK/SS1,2,3 TG2 V OUT1 INTV CC BOOST2 4.7F VPRG3 0.1F 1.8H V 3m OUT2 5V SW2 0.1F 10A 10F 0V 7817 TA01b BG2 330F TIME (10ms/DIV) BOOST1,2,3 + SENSE2 357k PLLIN/MODE SENSE2 FREQ V FB2 EXTV V PGND SGND CC OUT2 68.1k 7817 TA01a Rev A 1 Document Feedback For more information www.analog.comLTC7817 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW Bias Input Supply Voltage (V ) .............. 0.3V to 40V BIAS BOOST1, BOOST2, BOOST3 ....................... 0.3V to 46V Switch Voltage (SW1, SW2, SW3) ................ 5V to 40V RUN1, RUN2, RUN3 Voltages ..................... 0.3V to 40V 38 37 36 35 34 33 32 + FREQ 1 31 SW1 SENSE1 , SENSE1 Voltages ...................... 0.3V to 40V + PLLIN/MODE 2 30 BOOST1 SENSE2 , SENSE2 Voltages ..................... 0.3V to 40V + SS3 3 29 BG1 SENSE3 , SENSE3 Voltages ..................... 0.3V to 40V + SENSE3 SW3 4 28 EXTV Voltage ......................................... 0.3V to 30V CC SENSE3 5 27 TG3 INTV , (BOOST1-SW1), CC V 6 26 BOOST3 FB3 39 (BOOST2-SW2), (BOOST3-SW3) ............. 0.3V to 6V PGND I 7 25 BG3 TH3 TRACK/SS1, TRACK/SS2, SS3 Voltages ...... 0.3V to 6V SGND 8 24 V BIAS RUN1 9 23 EXTV ITH1, ITH2, ITH3 Voltages............................ 0.3V to 2V CC RUN2 10 22 INTV CC V Voltage............................................... 0.3V to 40V FB3 RUN3 11 21 BG2 V , V PLLIN/MODE Voltages ............... 0.3V to 6V FB1 FB2, SENSE2 12 20 BOOST2 VPRG3, FREQ, PGOOD1 Voltages ................ 0.3V to 6V 13 14 15 16 17 18 19 BG1, BG2, BG3, TG1, TG2, TG3 .......................... (Note 9) Operating Junction Temperature Range (Notes 2,8) LTC7817E, LTC7817I .......................... 40C to 125C UHF PACKAGE LTC7817J, LTC7817H ......................... 40C to 150C 38-LEAD (5mm 7mm) PLASTIC QFN Storage Temperature Range .................. 65C to 150C T = 150C, = 34.7C/W JMAX JA EXPOSED PAD (PIN 39) IS PGND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC7817EUHF PBF LTC7817EUHF TRPBF 7817 38-Lead (5mm x 7mm) Plastic QFN 40C to 125C AUTOMOTIVE PRODUCTS** LTC7817IUHF WPBF LTC7817IUHF WTRPBF 7817 38-Lead (5mm x 7mm) Plastic QFN 40C to 125C LTC7817JUHF WPBF LTC7817JUHF WTRPBF 7817 38-Lead (5mm x 7mm) Plastic QFN 40C to 150C LTC7817HUHF WPBF LTC7817HUHF WTRPBF 7817 38-Lead (5mm x 7mm) Plastic QFN 40C to 150C Contact the factory for parts specified with wider operating temperature ranges. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. **Versions of this part are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. These models are designated with a W suffix. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for thesemodels. Rev A 2 For more information www.analog.com + SENSE2 SENSE1 + V SENSE1 FB2 I V TH2 FB1 TRACK/SS2 I TH1 VPRG3 TRACK/SS1 TG2 PGOOD1 SW2 TG1