Datasheet LTC3370 (Analog Devices)

LTC3370 4-Channel 8A Configurable Buck DC/DCs
FeaTures DescripTion
n
8
×
1A Power Stages Configurable as 2, 3, or 4 Output
The LTC®3370 is a highly flexible multioutput power
Channels
supply IC. The device includes four synchronous buck n
8 Unique Output Configurations (1A to 4A Per Channel)
converters, configured to share eight 1A power stages, n
Independent VIN Supplies for Each DC/DC
each of which is powered from independent 2.25V to
(2.25V to 5.5V)
5.5V inputs. n
Low Total No Load Supply Current:
The DC/DCs are assigned to one of eight power configu- n
Zero Current In Shutdown (All Channels Off)
rations via pin programmable C1-C3 pins. The common n
63µA One Channel Active in Burst Mode® Operation
buck switching frequency may be programmed with an n
18µA Per Additional Channel
external resistor, synchronized to an external oscillator, n
Precision Enable Pin Thresholds for Autonomous
or set to a default internal 2MHz clock.
Sequencing
n 1MHz to 3MHz RT Programmable Frequency The operating mode for all DC/DCs may be programmed (2MHz Default) or PLL Synchronization via the PLL/MODE pin for Burst Mode or forced continuous n Temp Monitor Indicates Die Temperature mode operation. A PGOODALL output indicates when all n PGOODALL Pin Indicates All Enabled Bucks Are in enabled DC/DCs are within a specified percentage of their Regulation final output value. n 32-Lead 5mm × 5mm QFN Package To reduce input noise, the buck converters are phased in 90° steps. Precision enable pin thresholds facilitate
applicaTions
reliable power-up sequencing. The LTC3370 is available n General Purpose Multichannel Power Supplies: in a 32-lead 5mm × 5mm QFN package. Automotive, Industrial, Distributed Power Systems 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.
Typical applicaTion Buck Efficiency vs ILOAD
100 90 2.7V TO 5.5V 80 V 70 2.25V TO 5.5V V CC INA VINE 2.25V TO 5.5V V 2.2µH INB VINF 2.2µH 60 Burst Mode OPERATION VOUT1 SWA SWE VOUT3 V 1.2V/2A 50 IN = 3.3V SWB SWF 1.8V/2A V 324k 806k OUT = 1.8V 40 f OSC = 1MHz FB1 FB3 EFFICIENCY (%) L = 3.3µH 30 649k EN1 EN3 649k 1A BUCK LTC3370 20 2A BUCK 2.25V TO 5.5V V 10 3A BUCK INC VING 2.5V TO 5.5V V 4A BUCK 2.2µH IND VINH 2.2µH 0 V V OUT2 OUT4 1 10 100 1000 4000 1.5V/2A SWC SWG 2.5V/2A 715k SWD SWH 665k LOAD CURRENT (mA) 3370 TA01b FB2 FB4 649k EN2 EN4 309k
C3 C2 C1 BUCK1 BUCK2 BUCK3 BUCK4
0 0 0 2A 2A 2A 2A PLL/MODE TEMP 0 0 1 3A 1A 2A 2A RT PGOODALL 402k C1 C2 C3 GND 0 1 0 3A 1A 1A 3A 3370 TA01a 0 1 1 4A 1A 1A 2A 1 0 0 3A 2A – 3A 1 0 1 4A – 2A 2A 1 1 0 4A – 1A 3A 1 1 1 4A – – 4A 3370fb For more information www.linear.com/LTC3370 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Block Diagram Operation Buck Switching Regulators Buck Regulators with Combined Power Stages Power Failure Reporting Via PGOODALL Pin Temperature Monitoring and Overtemperature Protection Programming the Operating Frequency Applications Information Buck Switching Regulator Output Voltage and Feedback Network Buck Regulators Combined Buck Power Stages Input and Output Decoupling Capacitor Selection PCB Considerations Typical Applications Package Description Typical Application Related Parts