LTC3727/LTC3727-1 High Efficiency, 2-Phase Synchronous Step-Down Switching Regulators FEATURES DESCRIPTIO Wide Output Voltage Range: 0.8V V 14V The LTC 3727/LTC3727-1 are high performance dual OUT Out-of-Phase Controllers Reduce Required Input step-down switching regulator controllers that drive all Capacitance and Power Supply Induced Noise N-channel synchronous power MOSFET stages. A con- OPTI-LOOP Compensation Minimizes C stant frequency current mode architecture allows phase- OUT 1% Output Voltage Accuracy lockable frequency of up to 550kHz. Power loss and noise Power Good Output Voltage Monitor due to the ESR of the input capacitors are minimized by Phase-Lockable Fixed Frequency 250kHz to 550kHz operating the two controller output stages out of phase. Latched Short-Circuit Shutdown (LTC3727 Only) OPTI-LOOP compensation allows the transient response Dual N-Channel MOSFET Synchronous Drive to be optimized over a wide range of output capacitance and Wide V Range: 4V to 36V Operation IN ESR values. There is a precision 0.8V reference and a power Very Low Dropout Operation: 99% Duty Cycle good output indicator. A wide 4V to 30V (36V maximum) Adjustable Soft-Start Current Ramping input supply range encompasses all battery chemistries. Foldback Output Current Limiting A RUN/SS pin for each controller provides soft-start, and Output Overvoltage Protection on the LTC3727GN, optional timed, short-circuit shut- Low Shutdown I : 20A Q down. Current foldback limits MOSFET heat dissipation Selectable Constant Frequency or Burst Mode during short-circuit conditions when overcurrent latchoff Operation is disabled. Output overvoltage protection circuitry latches Small 28-Lead SSOP Package on the bottom MOSFET until V returns to normal. The LTC3727-1 Also Available in the 5mm 5mm QFN OUT FCB mode pin can select among Burst Mode, constant Package U frequency mode and continuous inductor current mode or APPLICATIO S regulate a secondary winding. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Telecom Systems Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including Automotive Systems 5481178, 5929620, 6177787, 6144194, 6100678, 5408150, 6580258, 6304066, 5705919. Battery-Operated Digital Devices TYPICAL APPLICATIO V IN 18V TO 28V + 22F 1F 50V 4.7 F CERAMIC V PGOOD INTV CERAMIC IN CC M1 M3 TG1 TG2 0.1 F 8H BOOST1 BOOST2 15H 0.1 F SW1 SW2 LTC3727/ M2 M4 BG1 BG2 LTC3727-1 PLLIN PGND + + SENSE1 SENSE2 1000pF 0.015 1000pF 0.015 SENSE1 SENSE2 V V OUT1 OUT2 5V V V 12V OSENSE1 OSENSE2 5A 105k 4A 280k I I TH1 TH2 1% 1% 56F 220pF 220pF + 47F RUN/SS1 SGND RUN/SS2 20k 20k 15V 1% 6V 1% SP 15k 15k SP 0.1 F 0.1 F M1, M2, M3, M4: FDS6680A 3727 F01 Figure 1. High Efficiency Dual 12V/5V Step-Down Converter 3727fc 1 + U ULTC3727/LTC3727-1 ABSOLUTE AXI U RATI GS (Note 1) Input Supply Voltage (V ).........................36V to 0.3V I I , V , V Voltages ...2.7V to 0.3V IN TH1, TH2 OSENSE1 OSENSE2 Top Side Driver Voltages Peak Output Current <10s (TG1, TG2, BG1, BG2) ... 3A (BOOST1, BOOST2) ...................................42V to 0.3V INTV Peak Output Current ................................ 50mA CC Switch Voltage (SW1, SW2) .........................36V to 5V Operating Temperature Range (Note 2) .. 40C to 85C INTV EXTV , (BOOST1-SW1), Junction Temperature (Note 3)............................. 125C CC, CC (BOOST2-SW2) ........................................8.5V to 0.3V Storage Temperature Range ................. 65C to 125C RUN/SS1, RUN/SS2, PGOOD ..................... 7V to 0.3V Lead Temperature + + SENSE1 , SENSE2 , SENSE1 , (Soldering, 10 sec, G Package)............................. 300C SENSE2 Voltages .....................................14V to 0.3V Solder Reflow Temperature (UH Package) ........... 265C PLLIN, PLLFLTR, FCB Voltages ........... INTV to 0.3V CC UUW PACKAGE/ORDER I FOR ATIO TOP VIEW ORDER PART ORDER PART TOP VIEW NUMBER NUMBER RUN/SS1 1 28 PGOOD + SENSE1 2 27 TG1 LTC3727EG LTC3727EUH-1 32 31 30 29 28 27 26 25 SENSE1 3 26 SW1 LTC3727EG-1 V 1 24 BOOST1 OSENSE1 4 25 BOOST1 V OSENSE1 PLLFLTR 2 23 V IN LTC3727IG-1 5 24 V PLLFLTR IN PLLIN 3 22 BG1 6 23 BG1 PLLIN FCB EXTV 4 21 CC 33 7 22 EXTV FCB CC I INTV 5 20 TH1 CC 8 21 INTV I CC TH1 SGND 6 19 PGND 9 20 PGND SGND 3.3V 7 18 BG2 OUT UH PART 10 19 BG2 I 8 17 BOOST2 3.3V OUT TH2 MARKING 11 18 BOOST2 I 9 10 11 12 13 14 15 16 TH2 12 17 SW2 V 37271 OSENSE2 13 16 TG2 SENSE2 + 14 15 RUN/SS2 SENSE2 UH PACKAGE 32-LEAD (5mm 5mm) PLASTIC QFN G PACKAGE T = 125C, = 34C/W JMAX JA 28-LEAD PLASTIC SSOP EXPOSED PAD (PIN 33) IS SGND T = 125C, = 95C/W JMAX JA (MUST BE SOLDERED TO PCB) Order Options Tape and Reel: Add TR Lead Free: Add PBF Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: