LT3988 Dual 60V Monolithic 1A Step-Down Switching Regulator Fea T Descrip T n Wide Input Range: The LT 3988 is a dual, current mode, step-down, DC/DC Operation from 4.1V to 60V converter that accepts two input voltages up to 60V (80V Overvoltage Lockout Protects Circuit Through transient), which may be driven from separate supplies or 80V Transients can be cascaded. High efficiency switches are included on n Two 1A Output Switching Regulators with Internal the die along with internal boost diodes and loop compensa- Power Switches tion. Both converters are capable of generating 1A outputs, n Short Circuit Robust are synchronized to a single oscillator programmable up n Adjustable 250kHz to 2.5MHz Switching Frequency, to 2.5MHz, and run with opposite phases, reducing input Synchronizable Over the Full Range ripple current. n Integrated Boost Diodes The switching frequency is set with a single resistor yield- n Integrated Loop Compensation ing a range of 250kHz to 2.5MHz, or a clock signal can n Anti-Phase Switching Reduces Ripple be applied to the SYNC pin. The LT3988s high switching n Low Shutdown I (<2A) Q frequency allows the use of small inductors and capacitors, n Uses Small Inductors and Ceramic Capacitors resulting in a very small dual output supply. The constant n Thermally Enhanced, 16-Lead MSOP Package switching frequency, combined with low impedance ce- ramic capacitors, results in low, predictable output ripple. a T A current mode PWM architecture provides fast transient response with cycle-by-cycle current limiting. Diode current n Commercial Vehicle Battery Regulation sense and thermal shutdown provide additional protection. n Industrial Supplies n Distributed Supply Regulation The LT3988 is available in a 16-lead MSOP package with L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks an exposed pad for low thermal resistance. of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical a T V IN Efficiency 7V TO 60V 90 4.7F TRANSIENT V V IN1 IN2 V = 5V OUT TO 80V EN/UVLO TRACK/SS2 85 1000pF TRACK/SS1 80 1000pF RT V = 3.3V OUT LT3988 200k SYNC 75 BD BOOST1 BOOST2 70 0.22F 0.22F 22H 15H V V OUT1 OUT2 SW1 SW2 65 5V, 1A 3.3V, 1A 60 DA1 DA2 57.6k 34k 55 FB1 FB2 V = 12V IN f = 500kHz GND SW 50 10.2k 10k 47F 47F 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 22pF I (A) OUT 3988 TA01 3988 TA01b 3988f 1 EFFICIENCY (%) ion pplica ions pplica ion uresLT3988 a Te Maxi Mu M r a T p in c F T (Note 1) TOP VIEW V (Notes 7, 8) .......................................... 0.3V to 80V IN DA1 1 16 V IN1 SW1 2 15 TRACK/SS1 BOOST ......................................................................80V BOOST1 3 14 FB1 BD 4 17 13 RT EN/UVLO (Note 7) .....................................................80V EN/UVLO 5 12 SYNC GND BOOST2 6 11 FB2 BOOST above SW .....................................................30V SW2 7 10 TRACK/SS2 EN/UVLO above V ...................................................6V DA2 8 9 V IN2 IN1 MSE PACKAGE RT, SYNC ....................................................................6V 16-LEAD PLASTIC MSOP TRACK/SS, FB ............................................................5V = 40C/W, = 10C/W JA JC EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB BD .............................................................................20V Operating Junction Temperature Range (Note 2) LT3988E ............................................ 40C to 125C LT3988I ............................................. 40C to 125C LT3988H ............................................ 40C to 150C Storage Temperature Range .................. 65C to 150C Lead Temperature (Soldering, 10 sec) ...................300C o r Der i n F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE* LT3988EMSE PBF LT3988EMSE TRPBF 3988 16-Lead Plastic MSOP 40C to 125C LT3988IMSE PBF LT3988IMSE TRPBF 3988 16-Lead Plastic MSOP 40C to 125C LT3988HMSE PBF LT3988HMSE TRPBF 3988 16-Lead Plastic MSOP 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: