LTC3803-3 Constant Frequency Current Mode Flyback DC/DC Controller in ThinSOT FEATURES DESCRIPTION n V and V Limited Only by External Components The LTC 3803-3 is a constant frequency current mode IN OUT n Adjustable Slope Compensation yback controller optimized for driving N-channel MOSFETs n Internal Soft-Start in high input voltage applications. Constant frequency n 55C to 150C Operating Temperature Range operation is maintained down to very light loads, resulting n Constant Frequency 300kHz Operation in less low frequency noise generation over a wide range n 1.5% Reference Accuracy of load currents. Slope compensation can be programmed n Current Mode Operation for Excellent Line and Load with an external resistor. Transient Response The LTC3803-3 provides 1.5% output voltage accuracy n No Minimum Load Requirement and consumes only 240A of quiescent current. Ground- n Low Quiescent Current: 240A referenced current sensing allows LTC3803-3-based con- n Low Pro le (1mm) SOT-23 Package verters to accept input supplies beyond the LTC3803-3s absolute maximum V . A micropower hysteretic start-up CC APPLICATIONS feature allows ef cient operation at high input voltages. For simplicity, the LTC3803-3 can also be powered from a high n Telecom Power Supplies V through a resistor, due to its internal shunt regulator. An IN n 42V and 12V Automotive Power Supplies internal undervoltage lockout shuts down the LTC3803-3 n Auxiliary/Housekeeping Power Supplies when the input voltage is too low to provide suf cient gate n Power over Ethernet Powered Devices drive to the external MOSFET. L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and ThinSOT and No R are trademarks of Linear Technology Corporation. All other SENSE The LTC3803-3 is available in a low pro le (1mm) 6-lead trademarks are the property of their respective owners. SOT-23 (ThinSOT ) package. TYPICAL APPLICATION 5V Output Nonisolated Telecom Housekeeping Power Supply Ef ciency vs Load Current 100 V IN V = 5V OUT 36V TO 72V UPS840 95 V OUT T1 5V 90 2A MAX 1F 300F* 85 10k 100V 6.3V X5R X5R 80 1F 10V 75 X5R V CC 70 I /RUN NGATE TH FDC2512 65 82k LTC3803-3 150pF 4.7k V = 36V IN 60 GND SENSE 200V V = 48V IN 470pF V = 60V IN 55 V FB 68m 220 V = 72V IN 50 20k 105k 250 500 750 1000 1250 1500 1750 2000 38033 TA01 LOAD CURRENT (mA) T1: COOPER CTX02-15242 38033 TA02 *THREE 100F UNITS IN PARALLEL 38033fd 1 EFFICIENCY (%)LTC3803-3 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) V to GND TOP VIEW CC Low Impedance Source .......................... 0.3V to 8V I /RUN 1 6 NGATE TH Current Fed ....................................... 25mA into V * GND 2 5 V CC CC V 3 4 SENSE NGATE Voltage .......................................... 0.3V to VCC FB V , I /RUN Voltages............................... 0.3V to 3.5V FB TH S6 PACKAGE 6-LEAD PLASTIC TSOT-23 SENSE Voltage ............................................ 0.3V to 1V T = 150C, = 192C/W JMAX JA NGATE Peak Output Current (<10s) ......................... 1A Operating Junction Temperature Range (Notes 2, 3) LTC3803E-3, LTC3803I-3 ................... 40C to 125C LTC3803H-3 ....................................... 40C to 150C LTC3803MP-3 .................................... 55C to 150C Storage Temperature Range ................... 65C to 150C Lead Temperature (Soldering, 10 sec) .................. 300C *LTC3803-3 internal clamp circuit self regulates V voltage to 9.5V. CC ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3803ES6-3 PBF LTC3803ES6-3 TRPBF LTCJS 6-Lead Plastic TSOT-23 40C to 125C LTC3803IS6-3 PBF LTC3803IS6-3 TRPBF LTCJT 6-Lead Plastic TSOT-23 40C to 125C LTC3803HS6-3 PBF LTC3803HS6-3 TRPBF LTCJT 6-Lead Plastic TSOT-23 40C to 150C LTC3803MPS6-3 PBF LTC3803MPS6-3 TRPBF LTCJT 6-Lead Plastic TSOT-23 55C to 150C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3803MPS6-3 LTC3803MPS6-3 TR LTCJT 6-Lead Plastic TSOT-23 55C to 150C 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: