POWER LOSS (mW) LTC3897 PolyPhase Synchronous Boost Controller with Input/ Output Protection FEATURES DESCRIPTION n Input Supply Range: 4.5V to 65V (Up to 75V Surge) The LTC 3897 is a synchronous boost DC/DC controller n Reverse Input Protection to 40V with surge stopper and ideal diode controller. n In-Rush Current Control, Overcurrent Protection The boost controller drives two N-channel power MOSFET and Output Disconnect for Boost Converter stages out-of-phase to reduce input and output capacitor n Input Voltage Surge Protection with Adjustable requirements, allowing the use of smaller inductors than Clamp Voltage the single-phase equivalent. Synchronous rectification n Onboard Ideal Diode Controller reduces power loss and eases thermal requirements. n Low Quiescent Current: 55A n The surge stopper controls the gate of an external 2-Phase Operation Reduces Required Input and N-channel MOSFET to protect against high voltage input Output Capacitance and Noise n transients and provides in-rush current control, over- Output Voltage Up to 60V n current protection and output disconnect for the boost Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE) converter. The integrated ideal diode controller drives for Logic-Level or Standard Threshold FETs n another N-channel MOSFET to replace a Schottky diode No External Bootstrap Diodes Required for reverse input protection and voltage holdup or peak detection. It controls the forward voltage drop across the APPLICATIONS MOSFET and minimizes reverse current flow. n Industrial The LTC3897 is available in thermally-enhanced 38-pin n Automotive leadless QFN or 38-lead TSSOP packages. n Military/Avionics All registered trademarks and trademarks are the property of their respective owners. Protectedby U.S. patents, including 5408150, 5481178, 5705919, 5929620, 6144194, 6177787, 6580258. TYPICAL APPLICATION 24V/10A 2-Phase Synchronous Boost Converter with Surge Protection and Reverse Protection Efficiency and Power Loss vs Output Current REVERSE CURRENT PROTECTION (IDEAL DIODE) 5m 3.5H INPUT VOLTAGE SURGE PROTECTION REVERSE INPUT VOLTAGE PROTECTION 100 100k IN-RUSH/OVERCURRENT PROTECTION BURST EFFICIENCY 90 V IN 2m + V SENSE1 BIAS 6V TO 80 10k 55V SENSE1 33F 549k 70 BG1 SPFB 0.1F 60 1k 10 12.1k BURST LOSS BOOST1 50 SW1 10nF 40 100 IS + IS TG1 30 5m 3.5H V OUT DG V = 12V IN 24V + 20 10 V = 24V CS OUT SENSE2 10A Burst Mode OPERATION SG LTC3897 SENSE2 10 FIGURE 17 CIRCUIT V IN 220F BG2 0 1 0.1F RUN 0.1F 0.001 0.01 0.1 1 10 SS OUTPUT CURRENT (A) BOOST2 15nF 3897 TA01b 8.66k SW2 I TH 1F TG2 475k INTV V PINS NOT SHOWN IN THIS CIRCUIT: CC FB 3897 TA01a DRV PLLIN/MODE, I , PHASMD, CC LIM 24.9k 4.7F CLKOUT, EXTV , SGEN, DGEN CC DTC DRVSET V OPERATES THROUGH TRANSIENTS UP TO 75V. IN DRVUV FREQ GND TMR WHEN V > 24V, V FOLLOWS V UP TO 57V. 1nF IN OUT IN Rev. A 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC3897 ABSOLUTE MAXIMUM RATINGS (Note 1) V , SGEN .................................................. 40V to 76 V INTV ......................................................... 0.3V to 6V IN CC + V , IS , IS , .........................................................76V EXTV ...................................................... 0.3V to 14V BIAS CC + + SENSE1 , SENSE2 , SENSE1 , SENSE2 ..................65V DRV , (BOOST1-SW1), (BOOST2-SW2) ....0.3V to 11V CC + CS ............................................................... 40V to 76V (SENSE1 -SENSE1 ), + SG, DG (Note 8) ...........................CS 0.3V to CS + 10V (SENSE2 -SENSE2 ) ............................. 0.3V to 0.3V BOOST1 and BOOST2 .................................0.3V to 71V I , SS, I , FREQ, LIM TH SW1 and SW2 ............................................... 5V to 65V PHASMD, DTC .......................0.3V to INTV + 0.3V CC BG1, BG2, TG1, TG2 ........................................... (Note 9) DRVUV, DRVSET ........................0.3V to INTV + 0.3V CC RUN, DGEN ................................................ 0.3V to 76V Operating Junction Temperature Range PLLIN/MODE, TMR, V , SPFB .................... 0.3V to 6V (Notes 2, 3) ........................................ 40C to 150C FB Storage Temperature Range .................. 65C to 150C PIN CONFIGURATION TOP VIEW TOP VIEW SGEN 1 38 TMR 2 SPFB DGEN 37 3 36 IS PLLIN/MODE + 38 37 36 35 34 33 32 FREQ 4 35 IS FREQ 1 31 DG PHASMD 5 34 DG PHASMD 2 30 CS 6 33 CS I LIM I 3 29 SG + LIM SENSE1 7 32 SG + SENSE1 4 28 V IN SENSE1 8 31 V IN SENSE1 5 27 TG1 9 TG1 DTC 30 DTC 6 26 SW1 39 39 10 29 SW1 DRVUV GND GND DRVUV 7 25 BOOST1 DRVSET 11 28 BOOST1 DRVSET 8 24 BG1 12 BG1 INTV 27 CC INTV 9 23 V CC BIAS 13 26 V RUN BIAS RUN 22 EXTV 10 CC I 14 25 EXTV CC TH I 21 DRV 11 TH CC SENSE2 15 24 DRV SENSE2 12 20 BG2 CC + 16 23 BG2 SENSE2 13 14 15 16 17 18 19 V 17 22 BOOST2 FB SS 18 21 SW2 19 TG2 CLKOUT 20 UHF PACKAGE 38-LEAD (5mm 7mm) PLASTIC QFN FE PACKAGE 38-LEAD PLASTIC TSSOP = 34C/W JA EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB = 28C/W JA EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB Rev. A 2 For more information www.analog.com + SENSE2 PLLIN/MODE V DGEN FB SS SGEN TMR CLKOUT SPFB TG2 IS SW2 + IS BOOST2