Datasheet LT3510 (Analog Devices)

LT3510 Monolithic Dual Tracking 2A Step-Down Switching Regulator
FEATURES DESCRIPTION
n
Wide Input Range: 3.1V to 25V
The LT®3510 is a dual current mode PWM step-down n
Two Switching Regulators with 2A Output Capability
DC/DC converter with two internal 2.5A 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 fi xed 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 effi ciency 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 recharging, resulting in ~95% maximum duty cycle. n DSP Power Supplies Each output can be independently disabled using its own n Disc Drives soft-start pin, or by using the SHDN pin the entire part can n DSL/Cable Modems be placed in a low quiescent current shutdown mode. n Wall Transformer Regulation n Distributed Power Regulation The LT3510 is available in a 20-lead TSSOP package with n PCI Cards exposed leadframe for low thermal resistance. 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 property of their respective owners.
TYPICAL APPLICATION 3.3V and 1.8V Dual 2A Step-Down Converter with Output Tracking
VIN
Effi ciency
12V 4.7μF VIN1 VIN2 61.9k 100 V SHDN R OUT = 3.3V T/SYNC 90 VOUT = 5V BST1 BST2 4.7μH 80 0.47μF 0.47μF 3.3μH SW1 SW2 70 V V OUT = 1.8V OUT = 2.5V PMEG4005 PMEG4005 B360A B360A 60 LT3510 50 V IND1 IND2 OUT1 VOUT2 3.3V V V 1.8V 40 OUT1 OUT2 EFFICIENCY (%) 2A 47μF 100μF 2A 24.9k 10k 30 PG1 PG2 FB1 FB2 20 VIN = 12V VC1 VC2 10 IOUT2 = 0A 470pF SS/TRACK1 SS/TRACK2 470pF FREQUENCY = 500kHz 0 GND 0 0.5 1 1.5 2 8.06k 10pF 40.2k 40.2k 47pF 8.06k LOAD CURRENT (A) 0.1μF 3510 TA01b 3510 TA01a 3510fe 1 Document Outline FEATURES DESCRIPTION APPLICATIONS 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