Datasheet LTC3374A (Analog Devices)

LTC3374A High Accuracy 8-Channel Parallelable 1A Buck DC/DCs
FeaTures DescripTion
n
8-Channel 1A Independent Step-Down DC/DCs
The LTC®3374A is a multioutput power supply IC consisting n
Master-Slave Configurable for Up to 4A of Output
of eight synchronous 1A buck converters, all powered from
Current with a Single Inductor
independent 2.25V to 5.5V input supplies. An upgraded n
Independent VIN Supplies for Each DC/DC
pin-compatible version of the LTC3374, the LTC3374A,
(2.25V to 5.5V)
has higher efficiency, improved output voltage accuracy n
All DC/DCs Have 0.8V to VIN Output Range
and an added overvoltage (OV) indicator. n
±1% VFB Accuracy, for Buck 1 (1A to 4A)
The DC/DCs may be used independently or in parallel to n
±1% PGOOD Accuracy
achieve higher output currents of up to 4A 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 5mm × 7mm QFN and TSSOP Packages To reduce input noise the buck converters are phased in n Pin-Compatible with LTC3374 90° steps. Precision enable pin thresholds simplify power- up sequencing. The LTC3374A is available in a 38-lead 5mm × 7mm QFN package as well as a 38-lead exposed
applicaTions
pad TSSOP package. n General Purpose Multichannel Power Supplies 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 n Industrial/Automotive/Communications owners.
Typical applicaTion Eight Synchronous 1A Buck Regulators Buck Efficiency vs ILOAD
BUCK 1 2.25V TO 5.5V V 100 IN1 SW1 0.8V TO VIN1 UP TO 1A 90 EN1 FB1 80 70 BUCK 2 60 2.25V TO 5.5V VIN2 SW2 0.8V TO VIN2 UP TO 1A 50 fOSC = 1MHz V V EN2 FB2 OUT = 1.8V 40 IN = 3.3V EFFICIENCY (%) VOUT = 1.8V THE EIGHT BUCKS CAN 30 Burst Mode OPERATION BE CONFIGURED IN 15 LTC3374A DIFFERENT MASTER/SLAVE • • 1A BUCK, L = 4.7µH, L DCR = 40mΩ • • 20 COMBINATIONS • • 2A BUCK, L = 2.2µH, L DCR = 13mΩ BUCK 8 10 3A BUCK, L = 1.8µH, L DCR = 10mΩ 2.25V TO 5.5V VIN8 SW8 0.8V TO V 4A BUCK, L = 1.0µH, L DCR = 8mΩ IN8 UP TO 1A 01m 10m 100m 1 4 EN8 FB8 LOAD CURRENT (A) 3374A TA01b 2.7V TO 5.5V VCC MODE SYNC PGOOD_ALL RT TEMP GND 3374A TA01a 3374af For more information www.linear.com/LTC3374A 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information (http://www.linear.com/product/LTC3374A#orderinfo) Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Buck Switching Regulators Buck Regulators with Combined Power Stages Power Failure Reporting Via PGOOD_ALL Pin Temperature Monitoring and Overtemperature Protection Programming the Operating Frequency Applications Information Buck Switching Regulator Output Voltage and Feedback Network Input and Output Decoupling Capacitor Selection Combined Buck Regulators Buck Regulators PCB Considerations Package Description Typical Application Related Parts