Datasheet LTC3375 (Analog Devices)

LTC3375 8-Channel Programmable, Parallelable 1A Buck DC/DCs
FeaTures DescripTion
n
8-Channel Independent Step-Down DC/DCs
The LTC®3375 is a digitally programmable high efficiency n
Master-Slave Configurable for Up to 4A Per Output
multioutput power supply IC. The DC/DCs consist of eight
Channel with a Single Inductor
synchronous buck converters (IOUT up to 1A each) all n
Independent VIN Supply for Each DC/DC
powered from independent 2.25V to 5.5V input supplies.
(2.25V to 5.5V)
DC/DC enables, output voltages, operating modes, and n
All DC/DCs Have 0.425V to VIN Output Voltage Range
phasing may all be independently programmed over I2C n
Precision Enable Pin Thresholds for Autonomous
or used in standalone mode via simple I/O with power-up
Sequencing (or I2C Control)
defaults. The DC/DCs may be used independently or in n 1MHz to 3MHz Programmable/Synchronizable parallel to achieve higher output currents of up to 4A per Oscillator Frequency (2MHz Default) output with a shared inductor. Alarm levels for high die n I2C Selectable Phasing (90° Steps) Per Channel temperature may also be programmed via I2C with a mask- n Programmable Power-On Reset/Watch Dog/ able IRQ output for monitoring DC/DC and system faults. Pushbutton Timing n Die Temperature Monitor Output Pushbutton ON/OFF/RESET control, power-on reset, and n 48-Lead (7mm × 7mm) QFN Package a watchdog timer provide flexible and reliable power-up sequencing and system monitoring. The LTC3375 is avail-
applicaTions
able in a low profile 48-lead 7mm × 7mm QFN package. n General Purpose Multichannel Power Supplies L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Industrial/Automotive/Communications
Typical applicaTion 8-Channel 1A Multioutput Buck Regulator
4V TO 40V VIN1 2.2µH 0.425V TO V
Buck Efficiency vs Load
IN1 VSHNT SW1 UP TO 1A ALWAYS-ON 10µF V 100 CC LDO FB1 90
LTC3375
MASTER FBV 1A BUCK CC 80 2A BUCK ON V 70 3A BUCK IN2 2.2µH SLAVE KILL SW2 0.425V TO VIN2 4A BUCK UP TO 1A 60 PB 10µF 50 PB FB2 40 EN1 EFFICIENCY (%) 30 Burst Mode OPERATION EN2 MASTER V EN3 IN = 3.3V • 20 VOUT = 1.8V EN4 • • f V 10 OSC = 2MHz EN5 IN7 2.2µH SLAVE L = 2.2µH SW7 0.425V TO VIN7 EN6 UP TO 1A 0 EN7 10µF 1 10 100 1000 EN8 LOAD CURRENT (mA) FB7 RST MASTER 3375 TA01b TEMP WDI WD0 VIN8 2.2µH SLAVE 0.425V TO V SW8 IN8 IRQ 2 UP TO 1A I2C 10µF SYNC FB8 RT CT 3375 TA01a 3375fd For more information www.linear.com/3375 1 Document Outline Features Applications Description Typical Application Table of Contents Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Buck Switching Regulators Buck Regulators with Combined Power Stages Pushbutton Interface Power-Up and Power-Down Via Pushbutton Power-Up and Power-Down Via Enable Pin or I2C I2C Interface I2C Bus Speed I2C Start and Stop Conditions I2C Byte Format I2C Acknowledge I2C Slave Address I2C Sub-Addressed Writing I2C Bus Write Operation I2C Bus Read Operation Error Condition Reporting Via RST and IRQ Pins Temperature Monitoring and Overtemperature Protection RESET_ALL Functionality Programming the Operating Frequency VCC Shunt Regulator Watchdog Timer Applications Information Buck Switching Regulator Output Voltage and Feedback Network Buck Regulators Combined Buck Regulators VCC Shunt Regulator Input and Output Decoupling Capacitor Selection Choosing the CT Capacitor Programming the Global Register Programming the RST and IRQ Mask Registers Status Byte Read Back Typical Applications Package Description Typical Application Related Parts