Datasheet LTC3371 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 4-Channel 8A Configurable Buck DC/DCs with Watchdog and Power-On Reset |
| Pages / Page | 26 / 1 — FEATURES. DESCRIPTION. 1A Buck Power Stages Configurable as 2, 3 or 4. … |
| File Format / Size | PDF / 1.1 Mb |
| Document Language | English |
FEATURES. DESCRIPTION. 1A Buck Power Stages Configurable as 2, 3 or 4. Output Channels
Model Line for this Datasheet
Text Version of Document
LTC3371 4-Channel 8A Configurable Buck DC/DCs with Watchdog and Power-On Reset
FEATURES DESCRIPTION
n
8
×
1A Buck Power Stages Configurable as 2, 3 or 4
The LTC®3371 is a highly flexible multioutput power supply
Output Channels
IC. The device includes four synchronous buck convert- n
8 Unique Output Configurations (1A to 4A Per Channel)
ers, configured to share eight 1A power stages, each of n
Independent VIN Supplies for Each DC/DC (2.25V to 5.5V)
which is powered from independent 2.25V to 5.5V inputs. n
Low Total No Load Supply Current:
The DC/DCs are assigned to one of eight possible power
n
15µA In Shutdown (All Channels Off)
configurations via pin programmable C1-C3 pins. The
n
68µA One Channel Active in Burst Mode® Operation
common buck switching frequency may be programmed
n
18µA Per Additional Channel
with an external resistor, synchronized to an external oscil- n
Precision Enable Pin Thresholds for Autonomous
lator, or set to a default internal 2MHz clock. The operating
Sequencing
mode for all DC/DCs may be programmed for Burst Mode n 1MHz to 3MHz RT Programmable Frequency or forced continuous mode operation. (2MHz Default) or PLL Synchronization n Temp Monitor Indicates Die Temperature The CT pin programs the timing parameters of four inde- n CT Programmed Watchdog Timer pendent RST pins as well as the watchdog timer. n Independent RST Pins Indicate Buck in Regulation To reduce input noise, the buck converters are phased in n Thermally Enhanced 38-Lead 5mm × 7mm QFN and 90° steps. Precision enable pin thresholds facilitate reli- TSSOP Packages able power sequencing. The LTC3371 is available in low profile 38-lead 5mm × 7mm QFN and TSSOP packages.
APPLICATIONS
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective n General Purpose Multichannel Power Supplies: owners. Automotive, Industrial, Distributed Power Systems
TYPICAL APPLICATION Buck Efficiency vs ILOAD
100 90 2.7V TO 5.5V 80 70 V 2.25V TO 5.5V V CC INA VINE 2.25V TO 5.5V 60 2.2µH VINB VINF 50 VOUT1 = 1.2V/2A SWA SWE VOUT3 = 1.8V/2A SWB SWF 324k 806k 40 EFFICIENCY (%) FB1 FB3 30 Burst Mode OPERATION EN1 EN3 V 1A BUCK 645k 649k 20 IN = 3.3V RST1 RST3 VOUT = 1.8V 2A BUCK LTC3371 10 f OSC = 1MHz 3A BUCK L = 3.3µH 2.25V TO 5.5V V 4A BUCK INC VING 2.5V TO 5.5V 0 V 2.2µH IND VINH 1 10 100 1000 4000 VOUT2 = 1.5V/2A SWC SWG VOUT4 = 2.5V/2A LOAD CURRENT (mA) SWD SWH 3371 TA01b 412k 665k FB2 FB4
C3 C2 C1 BUCK1 BUCK2 BUCK3 BUCK4
EN2 EN4 475k 309k RST2 RST4 0 0 0 2A 2A 2A 2A 0 0 1 3A 1A 2A 2A PLL/MODE TEMP RT WDI 0 1 0 3A 1A 1A 3A WDO CT 0 1 1 4A 1A 1A 2A C1 C2 C3 GND 3371 TA01 1 0 0 3A 2A – 3A 1 0 1 4A – 2A 2A 1 1 0 4A – 1A 3A 1 1 1 4A – – 4A 3371fb For more information www.linear.com/LTC3371 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Buck Switching Regulators Buck Regulators with Combined Power Stages Power Failure Reporting Via RST Pins Temperature Monitoring and Overtemperature Protection Programming the Operating Frequency Windowed Watchdog Timer Choosing the CT Capacitor 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 Revision History Typical Application Related Parts
FEATURES DESCRIPTION
n
8
×
1A Buck Power Stages Configurable as 2, 3 or 4
The LTC®3371 is a highly flexible multioutput power supply
Output Channels
IC. The device includes four synchronous buck convert- n
8 Unique Output Configurations (1A to 4A Per Channel)
ers, configured to share eight 1A power stages, each of n
Independent VIN Supplies for Each DC/DC (2.25V to 5.5V)
which is powered from independent 2.25V to 5.5V inputs. n
Low Total No Load Supply Current:
The DC/DCs are assigned to one of eight possible power
n
15µA In Shutdown (All Channels Off)
configurations via pin programmable C1-C3 pins. The
n
68µA One Channel Active in Burst Mode® Operation
common buck switching frequency may be programmed
n
18µA Per Additional Channel
with an external resistor, synchronized to an external oscil- n
Precision Enable Pin Thresholds for Autonomous
lator, or set to a default internal 2MHz clock. The operating
Sequencing
mode for all DC/DCs may be programmed for Burst Mode n 1MHz to 3MHz RT Programmable Frequency or forced continuous mode operation. (2MHz Default) or PLL Synchronization n Temp Monitor Indicates Die Temperature The CT pin programs the timing parameters of four inde- n CT Programmed Watchdog Timer pendent RST pins as well as the watchdog timer. n Independent RST Pins Indicate Buck in Regulation To reduce input noise, the buck converters are phased in n Thermally Enhanced 38-Lead 5mm × 7mm QFN and 90° steps. Precision enable pin thresholds facilitate reli- TSSOP Packages able power sequencing. The LTC3371 is available in low profile 38-lead 5mm × 7mm QFN and TSSOP packages.
APPLICATIONS
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective n General Purpose Multichannel Power Supplies: owners. Automotive, Industrial, Distributed Power Systems
TYPICAL APPLICATION Buck Efficiency vs ILOAD
100 90 2.7V TO 5.5V 80 70 V 2.25V TO 5.5V V CC INA VINE 2.25V TO 5.5V 60 2.2µH VINB VINF 50 VOUT1 = 1.2V/2A SWA SWE VOUT3 = 1.8V/2A SWB SWF 324k 806k 40 EFFICIENCY (%) FB1 FB3 30 Burst Mode OPERATION EN1 EN3 V 1A BUCK 645k 649k 20 IN = 3.3V RST1 RST3 VOUT = 1.8V 2A BUCK LTC3371 10 f OSC = 1MHz 3A BUCK L = 3.3µH 2.25V TO 5.5V V 4A BUCK INC VING 2.5V TO 5.5V 0 V 2.2µH IND VINH 1 10 100 1000 4000 VOUT2 = 1.5V/2A SWC SWG VOUT4 = 2.5V/2A LOAD CURRENT (mA) SWD SWH 3371 TA01b 412k 665k FB2 FB4
C3 C2 C1 BUCK1 BUCK2 BUCK3 BUCK4
EN2 EN4 475k 309k RST2 RST4 0 0 0 2A 2A 2A 2A 0 0 1 3A 1A 2A 2A PLL/MODE TEMP RT WDI 0 1 0 3A 1A 1A 3A WDO CT 0 1 1 4A 1A 1A 2A C1 C2 C3 GND 3371 TA01 1 0 0 3A 2A – 3A 1 0 1 4A – 2A 2A 1 1 0 4A – 1A 3A 1 1 1 4A – – 4A 3371fb For more information www.linear.com/LTC3371 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Buck Switching Regulators Buck Regulators with Combined Power Stages Power Failure Reporting Via RST Pins Temperature Monitoring and Overtemperature Protection Programming the Operating Frequency Windowed Watchdog Timer Choosing the CT Capacitor 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 Revision History Typical Application Related Parts
