LT3992 Monolithic Dual Tracking 3A Step-Down Switching Regulator Fea T Descrip T n Wide Input Range: The LT 3992 is a dual current mode PWM step-down DC/DC converter with two internal 4.6A switches. Inde- Operation from 3V to 60V n pendent input voltage, shutdown, feedback, soft-start, Independent Supply, Shutdown, Soft-Start, UVLO, UVLO current limit and comparator pins for each channel Programmable Current Limit and Programmable simplify complex power supply tracking and sequencing Power Good for Each 3A Regulator n requirements. Die Temperature Monitor n Adjustable/Synchronizable Fixed Frequency To optimize efficiency and component size, both convert- Operation from 250kHz to 2MHz with Synchronized ers have a programmable maximum current limit and are Clock Output synchronized to either a common external clock input, or n Independent Synchronized Switching Frequencies a resistor settable fixed 250kHz to 2MHz internal oscillator. Optimize Component Size A frequency divider is provided for channel 1 to further n Antiphase Switching optimize component size. At all frequencies, a 180 phase n Outputs Can Be Paralleled relationship between channels is maintained, reducing volt- n Flexible Output Voltage Tracking age ripple and component size. A clock output is available n Low Dropout: 95% Maximum Duty Cycle for synchronizing multiple regulators. n 5mm 5mm QFN Package Minimum input to output voltage ratios are improved by n FMEA Compliant 38-Pin Exposed Pad TSSOP Package allowing the switch to stay on through multiple clock cycles only switching off when the boost capacitor needs recharg- a T ing. Independent channel operation can be programmed n Automotive Supplies using the SHDN pin. Disabling both converters reduces n Distributed Supply Regulation the total quiescent current to <10A. L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical a T 12V and 5V 2-Stage Multi-Frequency Step-Down Converter Independent Synchronized V IN1 Switching Frequencies Extend 15V TO 60V 4.7F Full Frequency Input Range V OUT2 V V IN1 IN2 SHDN1 SHDN2 CH1 BST1 BST2 400kHz SW1 SW2 20V/DIV 22H 2.2H 0.1F 0.1F IND1 IND2 V V OUT2 OUT1 LT3992 5V 12V V V OUT1 OUT2 2A 1A CH2 22F 1600kHz 113k 42.2k 400kHz FB1 FB2 47F 1.6MHz 8.06k 8.06k 100k 5V/DIV CMPI1 CMPI2 FB1 PG CMPO1 CMPO2 SS1 SS2 3992 TA01b V = 60V 500ns/DIV IN ILIM1 ILIM2 V V C1 C2 CLKOUT 0.1F 33pF RT/SYNC CLKOUT 33pF 0.1F 1600kHz 680pF 680pF DIV T J GND 10nF 100k 60.4k 15k 48.7k 102k 10k 3992 TA01a 3992fa 1 For more information www.linear.com/LT3992 ion pplica ions pplica ion uresLT3992 a Te Maxi Mu M r a T (Note 1) V , SHDN1/2, CMPO1/2 .......................................60V V , T .............................................................. 100A IN1/2 C1/2 J SW1/2 ....................................................................V Operating Junction Temperature Range (Note 2) IN1/2 BST1/2 ......................................................................75V LT3992EUH ........................................ 40C to 125C BST1/2 Pin Above SW1/2 ..........................................25V LT3992IUH ......................................... 40C to 125C IND1/2, V .........................................................60V LT3992EFE ......................................... 40C to 125C OUT1/2 FB1/2, CMPI1/2, SS1/2 ................................................5V LT3992IFE .......................................... 40C to 125C RT/SYNC .....................................................................5V LT3992HFE ........................................ 40C to 150C DIV, ILIM1/2 .............................................................2.5V Storage Temperature Range .................. 65C to 150C p in c F T TOP VIEW 1 SW1 NC 38 2 37 NC IND1 TOP VIEW NC 3 36 V IN1 V 4 35 SHDN1 OUT1 5 SS1 NC 34 32 31 30 29 28 27 26 25 6 33 I BST1 BST1 1 24 ILIM1 LIM1 CMPO1 7 32 V C1 CMPO1 2 23 V C1 CMPI1 8 31 NC CMPI1 3 22 RT/SYNC 9 RT/SYNC FB1 30 FB1 4 21 CLKOUT 33 GND 10 39 29 CLKOUT FB2 5 20 T NC J GND FB2 11 28 T CMPI2 6 19 DIV J CMPO2 V CMPI2 12 27 DIV 7 18 C2 13 26 VC2 BST2 8 17 ILIM2 CMPO2 14 25 I BST2 LIM2 9 10 11 12 13 14 15 16 NC 15 24 SS2 16 SHDN2 V 23 OUT2 UH PACKAGE 17 22 V NC IN2 32-LEAD (5mm 5mm) PLASTIC QFN IND2 18 21 NC = 44C/W, = 7.3C/W JA JC(PAD) NC 19 20 SW2 EXPOSED PAD (PIN 33) IS GND, MUST BE SOLDERED TO PCB *DO NOT CONNECT FE PACKAGE 38-LEAD PLASTIC TSSOP = 17.5C/W, = 10C/W JA JC(PAD) EXPOSED PAD (PIN 39) 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 LT3992EUH PBF LT3992EUH TRPBF 3992 32-Lead (5mm 5mm) Plastic QFN 40C to 125C LT3992IUH PBF LT3992IUH TRPBF 3992 40C to 125C 32-Lead (5mm 5mm) Plastic QFN LT3992EFE PBF LT3992EFE TRPBF LT3992FE 38-Lead Plastic TSSOP 40C to 125C LT3992IFE PBF LT3992IFE TRPBF LT3992FE 38-Lead Plastic TSSOP 40C to 125C LT3992HFE PBF LT3992HFE TRPBF LT3992FE 38-Lead Plastic TSSOP 40C to 150C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: