Datasheet LT3501 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Monolithic Dual Tracking 3A Step-Down Switching Regulator |
| Pages / Page | 30 / 1 — FeaTures. DescripTion. Wide Input Range: 3.1V to 25V. Two Switching … |
| File Format / Size | PDF / 450 Kb |
| Document Language | English |
FeaTures. DescripTion. Wide Input Range: 3.1V to 25V. Two Switching Regulators with 3A Output Capability
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Text Version of Document
LT3501 Monolithic Dual Tracking 3A Step-Down Switching Regulator
FeaTures DescripTion
n
Wide Input Range: 3.1V to 25V
The LT®3501 is a dual-current mode PWM step-down n
Two Switching Regulators with 3A Output Capability
DC/DC converter with two internal 3.5A switches. Inde- n
Independent Supply to Each Regulator
pendent input voltage, feedback, soft-start and power n
Adjustable/Synchronizable Fixed Frequency
good pins for each channel simplify complex power
Operation from 250kHz to 1.5MHz
supply tracking/sequencing requirements. n
Antiphase Switching
Both converters are synchronized to either a common n
Outputs Can be Paralleled
external clock input or a resistor programmable fixed n Independent, Sequential, Ratiometric or Absolute 250kHz to 1.5MHz internal oscillator. At all frequencies, a Tracking Between Outputs 180° phase relationship between channels is maintained, n Independent Soft-Start and Power Good Pins reducing voltage ripple and component size. Programmable n Enhanced Short-Circuit Protection frequency allows for optimization between efficiency and n Low Dropout: 95% Maximum Duty Cycle external component size. n Low Shutdown Current: <10µA n 20-Lead TSSOP Package with Exposed Leadframe Minimum input-to-output voltage ratios are improved by allowing the switch to stay on through multiple clock
applicaTions
cycles, only switching off when the boost capacitor needs n recharging, resulting in ~95% maximum duty cycle. DSP Power Supplies n Disc Drives Each output can be independently disabled using its own n DSL/Cable Modems soft-start pin, or by using the SHDN pin the entire part can n Wall Transformer Regulation be placed in a low quiescent current shutdown mode. n Distributed Power Regulation The LT3501 is available in a 20-lead TSSOP package with L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the exposed leadframe for low thermal resistance. property of their respective owners.
Typical applicaTion 3.3V and 1.8V Dual 3A Step-Down Converter with Output Tracking Efficiency
VIN, 12V 100 V 4.7µF 90 OUT1 = 5V VOUT1 = 3.3V VIN1 VIN2 61.9k 80 SHDN RT/SYNC 70 V BST1 BST2 OUT1 = 1.8V VOUT1 = 2.5V 4.7µH 0.47µF 0.47µF 3.3µH 60 SW1 SW2 50 PMEG4005 PMEG4005 B360A LT3501 B360A 40 EFFICIENCY (%) VOUT2 IND1 IND2 30 1.8V, 3A V V 20 V OUT1 OUT2 V OUT1 IN = 12V 3.3V, 3A 24.9k 10k 100µF I PG1 PG2 10 OUT2 = 0A FREQUENCY = 500kHz 47µF FB1 FB2 0 VC1 VC2 0 0.5 1 1.5 2 2.5 3 LOAD CURRENT (A) 8.06k 470pF SS/TRACK1 SS/TRACK2 470pF GND 8.06k 3501 TA01b 10pF 40.2k 40.2k 47pF 0.1µF 3501 TA01a 3501fd 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Related Parts
FeaTures DescripTion
n
Wide Input Range: 3.1V to 25V
The LT®3501 is a dual-current mode PWM step-down n
Two Switching Regulators with 3A Output Capability
DC/DC converter with two internal 3.5A switches. Inde- n
Independent Supply to Each Regulator
pendent input voltage, feedback, soft-start and power n
Adjustable/Synchronizable Fixed Frequency
good pins for each channel simplify complex power
Operation from 250kHz to 1.5MHz
supply tracking/sequencing requirements. n
Antiphase Switching
Both converters are synchronized to either a common n
Outputs Can be Paralleled
external clock input or a resistor programmable fixed n Independent, Sequential, Ratiometric or Absolute 250kHz to 1.5MHz internal oscillator. At all frequencies, a Tracking Between Outputs 180° phase relationship between channels is maintained, n Independent Soft-Start and Power Good Pins reducing voltage ripple and component size. Programmable n Enhanced Short-Circuit Protection frequency allows for optimization between efficiency and n Low Dropout: 95% Maximum Duty Cycle external component size. n Low Shutdown Current: <10µA n 20-Lead TSSOP Package with Exposed Leadframe Minimum input-to-output voltage ratios are improved by allowing the switch to stay on through multiple clock
applicaTions
cycles, only switching off when the boost capacitor needs n recharging, resulting in ~95% maximum duty cycle. DSP Power Supplies n Disc Drives Each output can be independently disabled using its own n DSL/Cable Modems soft-start pin, or by using the SHDN pin the entire part can n Wall Transformer Regulation be placed in a low quiescent current shutdown mode. n Distributed Power Regulation The LT3501 is available in a 20-lead TSSOP package with L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the exposed leadframe for low thermal resistance. property of their respective owners.
Typical applicaTion 3.3V and 1.8V Dual 3A Step-Down Converter with Output Tracking Efficiency
VIN, 12V 100 V 4.7µF 90 OUT1 = 5V VOUT1 = 3.3V VIN1 VIN2 61.9k 80 SHDN RT/SYNC 70 V BST1 BST2 OUT1 = 1.8V VOUT1 = 2.5V 4.7µH 0.47µF 0.47µF 3.3µH 60 SW1 SW2 50 PMEG4005 PMEG4005 B360A LT3501 B360A 40 EFFICIENCY (%) VOUT2 IND1 IND2 30 1.8V, 3A V V 20 V OUT1 OUT2 V OUT1 IN = 12V 3.3V, 3A 24.9k 10k 100µF I PG1 PG2 10 OUT2 = 0A FREQUENCY = 500kHz 47µF FB1 FB2 0 VC1 VC2 0 0.5 1 1.5 2 2.5 3 LOAD CURRENT (A) 8.06k 470pF SS/TRACK1 SS/TRACK2 470pF GND 8.06k 3501 TA01b 10pF 40.2k 40.2k 47pF 0.1µF 3501 TA01a 3501fd 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Related Parts
