LT3570 1.5A Buck Converter, 1.5A Boost Converter and LDO Controller FEATURES DESCRIPTION n 2.5V to 36V Input Voltage Range The LT 3570 is a buck and boost converter with internal n Programmable Switching Frequency power switches and LDO controller. Each converter is from 500kHz to 2.1MHz designed with a 1.5A current limit and an input range from n Synchronizable Up to 2.75MHz 2.5V to 36V, making the LT3570 ideal for a wide variety n V : 0.8V of applications. Switching frequencies up to 2.1MHz are OUT(MIN) n Independent Soft-Start for Each Converter programmed with an external timing resistor and the n Separate V Supplies for Each Converter oscillator can be synchronized to an external clock up to IN n Duty Cycle Range: 0% to 90% at 1MHz 2.75MHz. n Available in 24-Lead (4mm 4mm) QFN and The LT3570 features a programmable soft-start function 20-Lead TSSOP Packages that limits the feedback voltage during start-up helping prevent overshoot and limiting inrush current. The LDO controller is capable of delivering up to 10mA of base APPLICATIONS current to an external NPN transistor. n Cable and Satellite Set-Top Boxes L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. n Automotive Systems All other trademarks are the property of their respective owners. n Telecom Systems n Dying Gasp Systems n TFT LCD Displays TYPICAL APPLICATION V IN 5V 10F V V V BIAS IN1 IN2 IN3 D3 Ef ciency SHDN1 SHDN1 BOOST 100 SHDN2 SHDN2 100nF V OUT2 3.3V SHDN3 SHDN3 SW2 3.3H 1A 95 D2 32.4k 6.8H D1 V OUT1 90 SW1 FB2 12V 275mA SS2 22F 143k V 85 C2 LT3570 f = 1.2MHz 10F FB1 22k 10nF 10.2k SW V = 5V IN SS1 80 10.0k V = 12V OUT1 1nF V C1 V = 3.3V OUT2 V = 2.5V OUT3 75 22k I = 275mA OUT1 NPN DRV Q1 I = 100mA OUT3 V OUT3 1nF 70 2.5V 0 0.2 0.4 0.6 0.8 1.0 10nF 100mA 22.1k I (A) OUT2 3570 TA01b FB3 2.2F R SYNC GND T 10.2k 15.8k 3570 TA01a 3570fb 1 EFFICIENCY (%)LT3570 ABSOLUTE MAXIMUM RATINGS (Note 1) V , V , V , V Voltage ..................................40V V , V Voltage ..........................................................3V IN1 IN2 IN3 BIAS C1 C2 BOOST Voltage .........................................................60V Maximum Junction Temperature........................... 125C BOOST Pin Above SW2 .............................................25V Operating Temperature Range (Note 2).. 40C to 125C NPN DRV Voltage .......................................................8V Storage Temperature Range SW1 Voltage .............................................................40V TSSOP ............................................... 65C to 150C SHDN1, SHDN2, SHDN3 Voltage ..............................40V QFN .................................................... 65C to 125C SYNC, R Voltage ........................................................3V Lead Temperature (Soldering, 10 sec) T SS1, SS2 Voltage ........................................................3V TSSOP Only ......................................................300C FB1, FB2, FB3 Voltage ...............................................10V PIN CONFIGURATION TOP VIEW TOP VIEW FB1 1 20 V C1 SHDN1 2 19 SS1 24 23 22 21 20 19 SHDN2 3 18 V IN1 V 1 18 V IN2 C2 SHDN3 4 17 GND V 2 17 SS2 IN2 SYNC 5 16 SW1 SW2 3 16 GND 21 25 R 6 15 SW2 T SW1 4 15 R T SS2 7 14 V GND SYNC IN2 5 14 V 8 13 BOOST GND 6 13 SHDN3 C2 FB2 9 12 V IN3 7 8 9 10 11 12 FB3 10 11 NPN DRV FE PACKAGE 20-LEAD PLASTIC TSSOP UF PACKAGE 24-LEAD (4mm s 4mm) PLASTIC QFN T = 125C, = 38C/W JMAX JA EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB T = 125C, = 37C/W JMAX JA EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3570EUF PBF LT3570EUF TRPBF 3570 24-Lead (4mm 4mm) Plastic QFN 40C to 125C LT3570IUF PBF LT3570IUF TRPBF 3570 24-Lead (4mm 4mm) Plastic QFN 40C to 125C LT3570EFE PBF LT3570EFE TRPBF LT3570FE 20-Lead Plastic TSSOP 40C to 125C LT3570IFE PBF LT3570IFE TRPBF LT3570FE 20-Lead Plastic TSSOP 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. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: