LTC3374 8-Channel Parallelable 1A Buck DC/DCs FEATURES DESCRIPTION n 8-Channel Independent Step-Down DC/DCs The LTC 3374 is a high efficiency multioutput power sup- n Master-Slave Configurable for Up to 4A per Output ply IC. The DC/DCs consist of eight synchronous buck Rail with a Single Inductor converters (1A each) all powered from independent 2.25V n Independent V Supplies for Each DC/DC to 5.5V input supplies. IN (2.25V to 5.5V) The DC/DCs may be used independently or in parallel to n All DC/DCs Have 0.8V to V Output Range IN achieve higher currents of up to 4A per output with a shared n Precision Enable Pin Thresholds for Autonomous inductor. The common buck switching frequency may be Sequencing programmed with an external resistor, synchronized to an n 1MHz to 3MHz Programmable/Synchronizable external oscillator, or set to a default internal 2MHz clock. Oscillator Frequency (2MHz Default) The operating mode for all DC/DCs may be programmed n Die Temperature Monitor Output via the MODE pin. n Thermally-Enhanced 38-Lead QFN (5mm 7mm) To reduce input noise the buck converters are phased in and TSSOP Packages 90 steps. Precision enable pin thresholds provide reli- APPLICATIONS able power-up sequencing. The LTC3374 is available in a compact 38-lead 5mm 7mm QFN package as well as a n General Purpose Multichannel Power Supplies 38-lead TSSOP package. n Industrial/Automotive/Communications L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 8-Channel 1A Multioutput Buck Regulator 2.2H V IN1 0.8V TO V IN1 V BUCK1 2.7V TO 5.5V CC UP TO 1A Buck Efficiency vs I 22F LOAD 100 MASTER LTC3374 90 V 2.2H 80 IN2 SLAVE 0.8V TO V IN2 BUCK2 UP TO 1A 70 22F 60 50 EN1 EN2 MASTER 1A BUCK 40 EN3 2A BUCK EN4 3A BUCK 30 2.2H V SLAVE EN5 IN7 4A BUCK 0.8V TO V IN7 BUCK7 20 EN6 FORCED CONTINUOUS MODE UP TO 1A 10F EN7 V = 3.3V, V = 1.8V 10 IN OUT EN8 f = 1MHz, L = 3.3H OSC PGOOD ALL MASTER 0 2000 4000 0 1000 3000 TEMP MODE LOAD CURRENT (mA) 2.2H V SLAVE IN8 0.8V TO V IN8 3374 TA01b BUCK8 UP TO 1A 10F SYNC RT 3374 TA01a 3374fc 1 For more information www.linear.com/LTC3374 EFFICIENCY (%)LTC3374 TABLE OF CONTENTS Features ..................................................... 1 Applications Information ................................ 17 Applications ................................................ 1 Buck Switching Regulator Output Voltage Typical Application ........................................ 1 and Feedback Network ............................................ 17 Description.................................................. 1 Buck Regulators ..................................................... 17 Absolute Maximum Ratings .............................. 3 Combined Buck Regulators..................................... 17 Pin Configuration .......................................... 3 Input and Output Decoupling Capacitor Selection... 17 Order Information .......................................... 3 PCB Considerations ................................................ 19 Electrical Characteristics ................................. 4 Package Description ..................................... 23 Typical Performance Characteristics ................... 6 Revision History .......................................... 25 Pin Functions .............................................. 11 Typical Application ....................................... 26 Block Diagram ............................................. 13 Related Parts .............................................. 26 Operation................................................... 14 Buck Switching Regulators ..................................... 14 Buck Regulators with Combined Power Stages ...... 14 Power Failure Reporting Via PGOOD ALL Pin ........ 15 Temperature Monitoring and Overtemperature Protection ............................................................... 15 Programming the Operating Frequency .................. 15 3374fc 2 For more information www.linear.com/LTC3374