LT3692A Monolithic Dual Tracking 3.5A Step-Down Switching Regulator Fea T Descrip T n Wide Input Range: The LT 3692A is a dual current mode PWM step-down Operation from 3V to 36V DC/DC converter with two internal 3.8A switches. Independent OVLO Protects Circuit Through 60V Transients input voltage, shutdown, feedback, soft-start, UVLO current n Independent Supply, Shutdown, Soft-Start, UVLO, limit and comparator pins for each channel simplify complex Programmable Current Limit and Programmable power supply tracking and sequencing requirements. Power Good for Each 3.5A Regulator To optimize efficiency and component size, both convert- n Die Temperature Monitor ers have a programmable maximum current limit and are n Adjustable/Synchronizable Fixed Frequency synchronized to either a common external clock input, or Operation from 250kHz to 2MHz with Synchronized a resistor settable fixed 250kHz to 2MHz internal oscillator. Clock Output A frequency divider is provided for channel 1 to further n Independent Synchronized Switching Frequencies optimize component size. At all frequencies, a 180 phase Optimize Component Size relationship between channels is maintained, reducing volt- n Antiphase Switching age ripple and component size. A clock output is available n Outputs Can Be Paralleled for synchronizing multiple regulators. n Flexible Output Voltage Tracking n Minimum input to output voltage ratios are improved by Low Dropout: 95% Maximum Duty Cycle n allowing the switch to stay on through multiple clock cycles 5mm 5mm QFN Package n only switching off when the boost capacitor needs recharg- FMEA Compliant 38-Pin Exposed Pad TSSOP Package ing. Independent channel operation can be programmed a T using the SHDN pin. Disabling both converters reduces the total quiescent current to <10A. n Automotive Supplies n Distributed Supply Regulation The LT3692A is an improved version of the LT3692 with L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks reduced minimum on-time. of Linear Technology Corporation. All other trademarks are the property of their respective owners. Independent Synchronized Switching Frequencies Typical a T Extend Full Frequency Input Range 3.3V and 1.2V 2-Stage Dual Step-Down Multi-Frequency Converter V OUT1 V IN1 CH1: 5.5V TO 36V 550kHz 4.7F V V IN1 IN2 SHDN1 SHDN2 BST1 BST2 0.1F SW1 SW2 CH2: 0.22F IND1 IND2 2.2MHz 4.7H 0.5H V V OUT2 OUT1 LT3692A 1.2V 3.3V V V OUT1 OUT2 1A 3692A TA01b 2.5A V = 30V IN 47F 24.9k FB1 FB2 4.02k 100p 47F 2.2MHz 550kHz 100k CMPI1 CMPI2 FB1 8.06k 8.06k PG CMPO1 CMPO2 SS1 SS2 ILIM1 ILIM2 V V C1 C2 CLKOUT RT/SYNC CLKOUT 0.1F 33pF 680pF 220pF 0.1F 2.2MHz DIV T J 22pF GND 10nF 100k 13k 68.1k 102k 40.2k 33.2k 3692a TA01a 3692a TA01c 3692afc 1 For more information www.linear.com/3692A ion pplica ions pplica ion uresLT3692A a Te Maxi Mu M r a T (Note 1) V , SHDN1/2, CMPO1/2 .......................................40V V , T .............................................................. 100A IN1/2 C1/2 J V Transient (Note 2) ...........................................60V Operating Junction Temperature Range (Note 3) IN1/2 SW1/2 ....................................................................V LT3692AEUH ..................................... 40C to 125C IN1/2 BST1/2 ......................................................................60V LT3692AIUH ...................................... 40C to 125C BST1/2 Pin Above SW1/2 ..........................................25V LT3692AHUH ..................................... 40C to 150C IND1/2, V .........................................................40V LT3692AEFE ...................................... 40C to 125C OUT1/2 FB1/2, CMPI1/2, SS1/2 ................................................5V LT3692AIFE ....................................... 40C to 125C RT/SYNC .....................................................................5V LT3692AHFE ...................................... 40C to 150C DIV, ILIM1/2 .............................................................3.0V Storage Temperature Range .................. 65C to 150C p in c F T TOP VIEW 1 38 SW1 NC 2 37 NC IND1 TOP VIEW 3 36 V NC IN1 4 35 SHDN1 V OUT1 5 34 SS1 NC 32 31 30 29 28 27 26 25 6 33 I BST1 LIM1 BST1 1 24 ILIM1 7 32 V CMPO1 C1 CMPO1 2 23 V C1 8 31 NC CMPI1 CMPI1 RT/SYNC 3 22 9 30 RT/SYNC FB1 FB1 4 21 CLKOUT 33 10 39 29 CLKOUT GND NC FB2 5 20 T J GND 11 28 T CMPI2 6 19 DIV FB2 J CMPO2 7 18 V 12 27 DIV CMPI2 C2 BST2 ILIM2 8 17 13 26 V CMPO2 C2 9 10 11 12 13 14 15 16 14 25 I BST2 LIM2 15 24 SS2 NC 16 23 SHDN2 V OUT2 UH PACKAGE 17 22 V NC 32-LEAD (5mm 5mm) PLASTIC QFN IN2 18 21 NC = 23C/W, = 1.5C/W IND2 JA JC(PAD) EXPOSED PAD (PIN 33) IS GND, MUST BE SOLDERED TO PCB 19 20 SW2 NC *DO NOT CONNECT FE PACKAGE 38-LEAD PLASTIC TSSOP = 17.5C/W, = 3C/W JA JC(PAD) EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB 3692afc 2 For more information www.linear.com/3692A V V OUT2 OUT1 DNC* DNC* IND2 IND1 DNC* DNC* SW2 SW1 V V IN2 IN1 SHDN2 SHDN1 SS2 SS1 ion igura on ings bsolu