POWER LOSS (mW) LTC3894 150V Low I Step-Down Q DC/DC Controller with 100% Duty Cycle Capability DESCRIPTION FEATURES n Wide Operating V Range: 4.5V to 150V The LTC 3894 is a high voltage step-down DC/DC switch- IN n Wide V Range: 0.8V to 60V ing regulator controller. It drives a P-channel power OUT n 9A I when Regulating 48V to 3.3V MOSFET switch allowing 100% duty cycle operation. It Q IN OUT n 16A I when Regulating 12V to 3.3V enables a low part count, simple, and robust solution for Q IN OUT n Very Low Dropout Operation: 100% Duty Cycle high reliability, high voltage applications. n Adjustable Input Overvoltage Lockout The LTC3894 operates over a wide input voltage range n Programmable PGOOD Undervoltage Monitor from 4.5V to 150V and can regulate output voltages n R or Inductor DCR Current Sensing SENSE from 0.8V to 60V. It offers excellent light load efficiency, n Selectable High Efficiency Burst Mode Operation or drawing only 9A quiescent current while regulating the Pulse-Skipping Mode at Light Loads output voltage with no load. Its peak current mode, con- n Programmable Fixed Frequency: 50kHz to 850kHz stant frequency architecture provides for good control of n Phase-Lockable Frequency: 75kHz to 800kHz switching frequency and output current limit. The switch- n Internal Fixed Soft-Start and External Programmable ing frequency can be programmed from 50kHz to 850kHz Soft-Start or Voltage Tracking with an external resistor and can be synchronized to an n Strong MOSFET Gate Driver with Selectable external clock from 75kHz to 800kHz. Undervoltage Lockout Thresholds n Optional External NMOS for Gate Driver Bias in High The LTC3894 offers programmable output voltage soft- start or tracking. Safety features include overvoltage, Power Applications overcurrent and overtemperature protection with a power good output monitor with adjustable threshold. APPLICATIONS The LTC3894 is available in a thermally enhanced 20-Pin n Automotive and Industrial Power Systems TSSOP package with leads removed to accommodate n Telecommunication Power Systems high voltage creepage and clearance requirements. n Distributed Power Systems All registered trademarks and trademarks are the property of their respective owners. TYPICAL APPLICATION Efficiency and Power Loss vs High Efficiency 150V to 5V Step-Down Regulator Load Current 22H 20m 100 10k V V IN OUT Burst Mode OPERATION 6V to 150V 5V, 3A 90 1nF 12F 330F 10F 80 1k 2 2 70 + GATE SENSE SENSE RUN EFFICIENCY 60 100 V IN PGOOD 50 0.47F 100k CAP 40 10 LTC3894 OVLO 422k POWER LOSS 30 DRVUV/EXTG PGUV 1 20 EXTS V FB V = 12V IN ITH 10 GND FREQ TRACK/SS PLLIN/MODE V = 24V IN 3.3nF 80.6k 0 0.1 47pF 0.0001 0.001 0.01 0.1 1 3 36.5k 5.76k 0.1F LOAD CURRENT (A) 3894 TA01b 3894 TA01a Rev. A 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC3894 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW Input Supply Voltage (V ), RUN .............. 0.3V to 150V IN GATE 1 20 V + IN SENSE , SENSE , PGOOD Voltage ............. 0.3V to 65V V -V Voltage ........................................ 0.3V to 10V IN CAP RUN 3 18 CAP V , PLLIN/MODE, PGUV, OVLO, FB EXTS Voltages ............................................. 0.3V to 6V + SENSE 5 16 DRVUV/EXTG 21 GND TRACK/SS Voltage (Note 11) .................... 0.3V to 2.8V SENSE 6 15 EXTS ITH, FREQ Voltage........................................ 0.3V to 5V ITH 7 14 OVLO DRVUV/EXTG Voltage .................................. 0.3V to 9V PGUV 8 13 FREQ V 9 12 PGOOD Operating Junction Temperature Range (Notes 2, 3) FB TRACK/SS 10 11 PLLIN/MODE LTC3894E, LTC3894I ......................... 40C to 125C LTC3894H .......................................... 55C to 150C FE PACKAGE 20(16)-LEAD PLASTIC TSSOP Storage Temperature Range .................. 65C to 150C T = 150C, = 38C/W JMAX JA Lead Temperature (Soldering, 10 sec) ...................300C EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB FOR RATED ELECTRICAL AND THERMAL CHARACTERISTICS ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3894EFE PBF LTC3894EFE TRPBF LTC3894FE 20(16)-Lead Plastic TSSOP 40C to 125C LTC3894IFE PBF LTC3894IFE TRPBF LTC3894FE 20(16)-Lead Plastic TSSOP 40C to 125C LTC3894HFE PBF LTC3894HFE TRPBF LTC3894FE 20(16)-Lead Plastic TSSOP 40C to 150C Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. ELECTRICAL CHARACTERISTICSThe l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at T = 25C. V = 12V, unless otherwise noted. (Note 2) A IN SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Input Supply V Input Voltage Operating Range (Note 4) DRVUV = 0V 4.5 150 V IN V Regulated Output Voltage Set Point 0.8 60 V OUT I No Load DC Supply Current (Note 5) Q Shutdown V Pin Current RUN = 0V 7 11 A IN Sleep Mode V Pin Current V = 2.5V, V = 0.83V 27 40 A IN SENSE FB V 3.2V, V = 0.83V 7 10 A SENSE FB Sleep Mode SENSE Pin Current (Note 6) V 3.2V, V = 0.83V 21 30 A SENSE FB Pulse-Skipping Mode V Pin Current V = 0.83V IN FB mA V = 0V 1.8 SENSE mA V = 3.3V 1.5 SENSE mA V = 5V 0.8 SENSE Rev. A 2 For more information www.analog.com