LT3506/LT3506A Dual Monolithic 1.6A Step-Down Switching Regulator FEATURES DESCRIPTION n Wide Input Voltage Range, 3.6V to 25V The LT 3506 is a dual current mode PWM step-down DC/DC n Two 1.6A Output Switching Regulators with Internal converter with internal 2A power switches. Both convert- Power Switches ers are synchronized to a single oscillator and run with n Constant Switching Frequency opposite phases, reducing input ripple current. The output LT3506: 575kHz voltages are set with external resistor dividers, and each LT3506A: 1.1MHz regulator has independent shutdown and soft-start circuits. n Anti-Phase Switching Reduces Ripple Each regulator generates a power-good signal when its n Accurate 0.8V Reference, 1% output is in regulation, easing power supply sequencing n Independent Shutdown/Soft-Start Pins and interfacing with microcontrollers and DSPs. n Independent Power Good Indicators Ease Supply The LT3506 switching frequency is 575kHz and the LT3506A Sequencing is 1.1MHz. These high switching frequencies allow the n Uses Small Inductors and Ceramic Capacitors use of tiny inductors and capacitors, resulting in a very n Small 16-Lead Thermally Enhanced 5mm 4mm small dual 1.6A output solution. Constant frequency and DFN and TSSOP Surface Mount Packages ceramic capacitors combine to produce low, predictable output ripple voltage. With its wide input range of 3.6V to 25V, the LT3506 regulates a wide variety of power sources, APPLICATIONS from 4-cell batteries and 5V logic rails to unregulated wall n Disk Drives transformers, lead acid batteries and distributed-power n DSP Power Supplies supplies. Current mode PWM architecture provides fast n Wall Transformer Regulation transient response with simple compensation components n Distributed Power Regulation and cycle-by-cycle current limiting. Frequency foldback n DSL Modems and thermal shutdown provide additional protection. n Cable Modems 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 Ef ciency V IN 1/2 BAT-54A 4.5V TO 25V 100 V = 5V IN 22F V V 1/2 BAT-54A IN1 IN2 BOOST1 BOOST2 90 V = 3.3V OUT 0.22F 0.22F 4.7H 6.4H V V OUT1 OUT2 1.8V 3.3V SW1 SW2 1.6A 1.6A 80 V = 1.8V OUT 18.7k 33.2k FB1 FB2 1000pF 2200pF 70 V V C1 C2 D1 D2 47F 15k 15k LT3506 10k 10.7k 22F 60 RUN/SS1 RUN/SS2 100k 1.5nF 1.5nF 3506 TA01a PGOOD1 50 0 0.5 1.0 1.5 2.0 100k I (A) PGOOD2 OUT 3506 TA01b D1, D2: ON SEMI MBR5230LT3 GND PGOOD1 PGOOD2 3506afc 1 EFFICIENCY (%)LT3506/LT3506A ABSOLUTE MAXIMUM RATINGS (Note 1) V Voltage ................................................. 0.3V to 25V Maximum Junction Temperature .......................... 125C IN BOOST Pin Voltage ...................................................50V Operating Temperature Range (Note 2) BOOST Pin Above SW Pin .........................................25V E Grade ................................................40C to 85C PG Pin Voltage ..........................................................25V I Grade ............................................... 40C to 125C RUN/SS, FB, V Pins ................................................5.5V Storage Temperature Range .................. 65C to 125C C PIN CONFIGURATION TOP VIEW TOP VIEW BOOST1 1 16 FB1 BOOST1 1 16 FB1 SW1 2 15 V SW1 2 15 V C1 C1 V 3 14 PG1 V 3 14 PG1 IN1 IN1 V 4 13 RUN/SS1 V 4 13 RUN/SS1 IN1 IN1 17 17 V 5 12 RUN/SS2 V 5 12 RUN/SS2 IN2 IN2 V 6 11 PG2 V 6 11 PG2 IN2 IN2 SW2 7 10 V SW2 7 10 V C2 C2 BOOST2 8 9 FB2 BOOST2 8 9 FB2 FE PACKAGE DHD PACKAGE 16-LEAD PLASTIC TSSOP NARROW 16-LEAD PLASTIC DFN T = 125C, = 45C/W, = 10C/W T = 125C, = 43C/W, = 4.3C/W JMAX JA JC JMAX JA JC EXPOSED PAD (PIN 17) IS GND MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 17) IS GND MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3506EDHD PBF LT3506EDHD TRPBF 3506 16-Lead (5mm 4mm) Plastic DFN 40C to 85C LT3506AEDHD PBF LT3506AEDHD TRPBF 3506A 40C to 85C 16-Lead (5mm 4mm) Plastic DFN LT3506IDHD PBF LT3506IDHD TRPBF 3506 40C to 125C 16-Lead (5mm 4mm) Plastic DFN LT3506AIDHD PBF LT3506AIDHD TRPBF 3506A 40C to 125C 16-Lead (5mm 4mm) Plastic DFN LT3506EFE PBF LT3506EFE TRPBF 3506EFE 16-Lead Plastic TSSOP Narrow 40C to 85C LT3506AEFE PBF LT3506AEFE TRPBF 3506AEFE 16-Lead Plastic TSSOP Narrow 40C to 85C LT3506IFE PBF LT3506IFE TRPBF 3506IFE 16-Lead Plastic TSSOP Narrow 40C to 125C LT3506AIFE PBF LT3506AIFE TRPBF 3506AIEFE 16-Lead Plastic TSSOP Narrow 40C to 125C LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3506EDHD LT3506EDHD TR 3506 40C to 85C 16-Lead (5mm 4mm) Plastic DFN LT3506AEDHD LT3506AEDHD TR 3506A 40C to 85C 16-Lead (5mm 4mm) Plastic DFN LT3506IDHD LT3506IDHD TR 3506 40C to 125C 16-Lead (5mm 4mm) Plastic DFN LT3506AIDHD LT3506AIDHD TR 3506A 40C to 125C 16-Lead (5mm 4mm) Plastic DFN LT3506EFE LT3506EFE TR 3506EFE 16-Lead Plastic TSSOP Narrow 40C to 85C LT3506AEFE LT3506AEFE TR 3506AEFE 16-Lead Plastic TSSOP Narrow 40C to 85C LT3506IFE LT3506IFE TR 3506IFE 16-Lead Plastic TSSOP Narrow 40C to 125C LT3506AIFE LT3506AIFE TR 3506AIEFE 16-Lead Plastic TSSOP Narrow 40C to 125C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. 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