Datasheet LTC3853 (Analog Devices)

LTC3853 Triple Output, Multiphase Synchronous Step-Down Controller
FEATURES DESCRIPTION
n
Triple, 120
°
Phased Controllers Reduce Required
The LTC®3853 is a high performance triple output step-
Input Capacitance and Power Supply Induced Noise
down switching regulator controller that drives all N- n
Configurable as a 180° Dual Phase Controller Plus a
channel synchronous power MOSFET stages. Power loss
Single Phase Controller
and supply noise are minimized by operating the output n
The Third Phase Can Regulate Up to a 13.5V Output
stages out of phase. The part can be configured as a dual n
High Efficiency: Up to 92%
phase controller plus a single phase controller if needed. n
RSENSE or DCR Current Sensing
The part can also be configured to provide a single 3-phase n
±0.75% 0.8V Output Voltage Accuracy
output for even higher output currents. n
Phase-Lockable Fixed Frequency 250kHz to 750kHz
A wide 4.5V to 24V (28V maximum) input voltage sup- n Supports Pre-Biased Outputs ply range encompasses most battery chemistries and n Dual N-Channel MOSFET Synchronous Drive intermediate bus voltages. Phase 3 can regulate output n Wide VIN Range: 4.5V to 24V Operation (28V Abs Max) voltages up to 13.5V. A constant-frequency current mode n Adjustable Soft-Start Current Ramping or Tracking architecture allows for a phase-lockable frequency up to n Foldback Output Current Limiting 750kHz. n Output Overvoltage Protection n Dual Power Good Output Voltage Monitors Independent TK/SS pins for each output ramps the output n 40-Lead 6mm × 6mm QFN Package voltages and can be configured for coincident or ratiometric L, LT, LTC, LTM, Linear Technology, Burst Mode, Polyphase and the Linear logo are registered tracking. Current foldback limits MOSFET heat dissipation trademarks of Linear Technology Corporation. All other trademarks are the property of their during short-circuit conditions. The MODE/PLLIN pin respective owners. Protected by U.S. Patents, including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6304066, 6580258. selects among Burst Mode® operation, pulse-skipping or continuous inductor current modes.
TYPICAL APPLICATION High Efficiency Triple 5V/3.3V/1.2V Step-Down Converter
VIN 7V TO 24V 22µF 4.7µF 50V VIN INTVCC TG1 TG2 PGOOD12 0.1µF 2.2µH PGOOD3 BOOST1,2,3 SW1,2,3 2.2µH 1µH SW1 SW2 BG1 LTC3853 BG2 2.2k 1k 2.2k fIN MODE/PLLIN PGND 500kHz 0.1µF ILIM FREQ/PLLFLTR 0.1µF 0.1µF SENSE1+ SENSE2+ SENSE2– VOUT2 VFB2 3.3V SENSE1– 63.4k V 5A OUT1 10nF VOUT3 5V V + FB1 1.2V 100µF 5A RUN1,2,3 105k 10k 20k 10k 5A ITH1,2,3 6V 1500pF TG3 220pF VFB3 SW3 + + SGND BG3 20k 100µF 100µF 20k 15k SENSE3+ 6V 10V SENSE3– TK/SS1,2,3 0.1µF 3853fc For more information www.linear.com/LTC3853 1 Document Outline Features Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts