LT3504IUFD#PBF Analog Devices

LT3504 Quad 40V/1A Step-Down Switching Regulator with 100% Duty Cycle Operation Fea T Descrip T n Wide Input Range: 3.2V to 40V The LT 3504 consists of four 1A output current buck n Four 1A Outputs regulators. The LT3504 has a wide operating input range n 100% Duty Cycle Operation of 3.2V to 40V. An on-chip boost regulator allows each n Resistor-Programmed Constant Frequency channel to operate up to 100% duty cycle and eliminates n Short-Circuit Robust the need for four external charge pump circuits. The LT3504 n Wide SYNC Range: 350kHz to 2.2MHz is designed to minimize external component count and n Anti-Phase Switching Reduces Ripple results in a simple and small application circuit. n 800mV FB Voltage The LT3504 operates robustly in fault conditions. Cycle- n Independent Run/Soft-Start Pins by-cycle peak current limit and catch diode current limit n Shutdown with UVLO sensing protect the part during overload conditions. Ther- n Internal Compensation mal shutdown protects the power switches at elevated n Thermal Shutdown temperatures. Soft-start helps keep the peak inductor n Tiny 28-Lead (4mm 5mm) Thermally Enhanced current under control during startup. QFN Package The LT3504 also features output voltage tracking and sequencing, programmable frequency, programmable a T undervoltage lockout, and a power good pin to indicate n Automotive Battery Regulation when all outputs are in regulation. n Industrial Control Supplies L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n of Linear Technology Corporation. All other trademarks are the property of their respective Wall Transformer Regulation owners. n Distributed Supply Regulation Typical a T Quad Buck Regulator in 4 5 QFN LT3504 Start-Up and Shutdown Waveform. V (Top Trace) Is Ramped IN 10H from 0V Up to 8V and Then Back Down SW4 5V/1A 52.3k to 0V. The Other Four Traces Are the 10F DA4 SKY FB4 Output Voltages of All Four Channels LT3504 10k 1F 10H 6.8H V IN V 1V/DIV IN 5.4V to 20V SW5 SW3 3.3V/1A 5V CHANNEL BEGINS TRANSIENT TO 40V 31.6k 10F 100% DC OPERATION EN/UVLO DA3 V FB3 IN 3.3V CHANNEL BEGINS CH4 1V/DIV V IN 100% DC OPERATION 10k V IN V 4.7H IN CH3 1V/DIV UVLO = ~2.9V RUN/SS1 SW2 2.5V/1A PARTS SHUTS CH2 1V/DIV RUN/SS2 OFF 22.1k 1F 22F RUN/SS3 DA2 CH1 1V/DIV RUN/SS4 FB2 10k 50nF 3504 TA01b 3.3H RT/SYNC 100ms/DIV SW1 1.8V/1A 1F 24.9k 18.2k DA1 22F FB1 GND 20k 3504 TA01a f = 1MHz SW 3504fa 1 For more information www.linear.com/LT3504 ion pplica ions pplica ion uresLT3504 a Te Maxi Mu M r a T p in c F T (Note 1) TOP VIEW EN/UVLO Pin .............................................................40V EN/UVLO Pin Above V Pin ........................................5V IN V Pin ......................................................................40V IN 28 27 26 25 24 23 1 22 SKY Pin .....................................................................46V DA2 FB2 SW2 2 21 FB3 SW5 Pin ....................................................................47V DA3 3 20 FB1 RUN/SS Pins ...............................................................6V SW3 4 19 FB4 29 FB Pins ........................................................................6V GND SW1 5 18 GND RT/SYNC Pin ...............................................................6V 6 17 DA1 RT/SYNC PG Pin .......................................................................25V SW4 7 16 EN/UVLO Operating Junction Temperature Range (Notes 2, 8) DA4 8 15 RUN/SS3 9 10 11 12 13 14 LT3504EUFD .......................................... 40C to 125C LT3504IUFD ........................................... 40C to 125C Storage Temperature Range .................. 65C to 150C UFD PACKAGE 28-LEAD (4mm 5mm) PLASTIC QFN = 43C/W JA EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB o r Der i n F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT3504EUFD PBF LT3504EUFD TRPBF 3504 28-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3504IUFD PBF LT3504IUFD TRPBF 3504 28-Lead (4mm 5mm) Plastic QFN 40C to 125C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: