LT3999 Low Noise, 1A, 1MHz Push-Pull DC/DC Driver with Duty Cycle Control FEATURES DESCRIPTION n Wide Input Operating Range: 2.7V to 36V The LT 3999 is a monolithic, high voltage, high frequency n Dual 1A Switches with Programmable Current Limit DC/DC transformer driver providing isolated power in a n Programmable Switching Frequency: 50kHz to 1MHz small solution footprint. n Frequency Synchronization Up to 1MHz The LT3999 has two 1A current limited power switches n V Compensation Using Duty Cycle Control IN that switch out of phase. The duty cycle is programmable n Low Noise Topology to adjust the output voltage. The switching frequency is n Programmable Input Over and Undervoltage Lockout programmed up to 1MHz and can be synchronized to an n Cross Conduction Prevention Circuitry external clock for more accurate placement of switcher n Programmable Soft-Start harmonics. The input operating range is programmed n Low Shutdown Current: <1A with the precision undervoltage and overvoltage lockouts. n 10-Lead MSOP and DFN Packages The supply current is reduced to less than 1A during shutdown. A user-defined RC time constant provides an APPLICATIONS adjustable soft-start capability by limiting the inrush cur- rent at start-up. n Low Noise Isolated Supplies n Medical Instrument and Safety The LT3999 is available in a 10-lead MSOP and 3mm n Distributed Power 3mm DFN package with exposed pad. n Multiple Output Supplies L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Positive-to-Negative Supplies n Noise Immunity in Data Acquisition, RS232 andRS485 TYPICAL APPLICATION LT3999 Line Regulation with 12V to 12V, 10W Low Noise Isolated DC/DC Converter Duty Cycle Control V IN 16 12V 10F 16V 15 V IN 15.3H V OUT SYNC 12V SWA 14 0.8A 255k UVLO 10F 16V I = 400mA 13 OVLO/DC OUT I = 200mA OUT RDC 10k 12 LT3999 15.8k I = 800mA OUT 11 3999 TA01a SWB RT 10 ILIM/SS 9 RBIAS 28k GND 0.1F 49.9k 500kHz 8 10 11 12 13 14 15 16 17 18 INPUT VOLTAGE (V) 3999 TA01b 3999fa 1 For more information www.linear.com/LT3999 OUTPUT VOLTAGE (V)LT3999 ABSOLUTE MAXIMUM RATINGS (Note 1) SWA, SWB ................................................. 0.3V to 80V Storage Temperature Range .................. 65C to 150C V , UVLO .................................................. 0.3V to 60V Lead Temperature (Soldering, 10 sec) IN OVLO/DC, SYNC ......................................... 0.3V to 8V MSOP ...............................................................300C Operating Junction Temperature Range (Note 2) LT3999E ............................................ 40C to 125C LT3999I ............................................. 40C to 125C LT3999H ............................................ 40C to 150C LT3999MP ......................................... 55C to 150C PIN CONFIGURATION TOP VIEW TOP VIEW SWA 1 10 SWB SWA 1 10 SWB RBIAS 2 9 ILIM/SS RBIAS 2 9 ILIM/SS 11 11 V 3 8 SYNC V 3 8 SYNC IN IN GND GND UVLO 4 7 RT UVLO 4 7 RT OVLO/DC 5 6 RDC OVLO/DC 5 6 RDC MSE PACKAGE 10-LEAD PLASTIC MSOP DD PACKAGE = 40CW, = 10CW JA JC 10-LEAD (3mm 3mm) PLASTIC DFN EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB = 43C/W, = 5.5C/W JA JC EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3999EMSE PBF LT3999EMSE TRPBF LTGKR 10-Lead Plastic MSOP 40C to 125C LT3999IMSE PBF LT3999IMSE TRPBF LTGKR 10-Lead Plastic MSOP 40C to 125C LT3999HMSE PBF LT3999HMSE TRPBF LTGKR 10-Lead Plastic MSOP 40C to 150C LT3999MPMSE PBF LT3999MPMSE TRPBF LTGKR 10-Lead Plastic MSOP 55C to 150C LT3999EDD PBF LT3999EDD TRPBF LGKQ 10-Lead (3mm 3mm) Plastic DFN 40C to 125C LT3999IDD PBF LT3999IDD TRPBF LGKQ 10-Lead (3mm 3mm) Plastic DFN 40C to 125C 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 nonstandard lead based finish parts. For more information on lead free part marking, go to: