LTC3803 Constant Frequency Current Mode Flyback DC/DC Controller in ThinSOT FEATURES DESCRIPTION n V and V Limited Only by External Components The LTC 3803 is a constant frequency current mode yback IN OUT n Adjustable Slope Compensation controller optimized for driving N-channel MOSFETs in high n Internal Soft-Start input voltage applications. Constant frequency operation n Constant Frequency 200kHz Operation is maintained down to very light loads, resulting in less n 1.5% Reference Accuracy low frequency noise generation over a wide range of load n Current Mode Operation for Excellent Line and Load currents. Slope compensation can be programmed with Transient Response an external resistor. n No Minimum Load Requirement The LTC3803 provides 1.5% output voltage accuracy and n Low Quiescent Current: 240A consumes only 240A of quiescent current. Ground-refer- n Low Pro le (1mm) SOT-23 Package enced current sensing allows LTC3803-based converters to accept input supplies beyond the LTC3803s absolute maximum V . A micropower hysteretic start-up feature APPLICATIONS CC allows ef cient operation at high input voltages. For sim- n Telecom Power Supplies plicity, the LTC3803 can also be powered from a high V IN n 42V and 12V Automotive Power Supplies through a resistor, due to its internal shunt regulator. An n Auxiliary/Housekeeping Power Supplies internal undervoltage lockout shuts down the LTC3803 n Power Over Ethernet when the input voltage is too low to provide suf cient L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks gate drive to the external MOSFET. and ThinSOT and No R are trademarks of Linear Technology Corporation. All other SENSE trademarks are the property of their respective owners. The LTC3803 is available in a low pro le (1mm) 6-lead SOT-23 (ThinSOT) package. TYPICAL APPLICATION 5V Output Nonisolated Telecom Housekeeping Power Supply Ef ciency vs Load Current 90 V IN 36V TO 72V UPS840 V = 36V IN 80 V OUT T1 5V 70 4.7F 300F* 2A MAX V = 48V IN 10k 100V 6.3V 60 X5R X5R V = 60V IN 10F 50 10V V = 72V IN X5R V 40 CC I /RUN NGATE FDC2512 TH 30 56k LTC3803 20 GND SENSE 0.0022F V 10 FB 68m 0 20k 105k 1 0.1 10 3803 TA01 I (A) OUT T1: COOPER CTX02-15242 3803 TA02 *THREE 100F UNITS IN PARALLEL 3803fc 1 EFFICIENCY (%)LTC3803 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V to GND CC Low Impedance Source ........................... 0.3V to 8V I /RUN 1 6 NGATE TH GND 2 5 V CC Current Fed ........................................25mA into V * CC V 3 4 SENSE FB NGATE Voltage ............................................0.3V to V CC V , I /RUN Voltages............................... 0.3V to 3.5V S6 PACKAGE FB TH 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, LTC3803I .......................... 40C to 125C LTC3803H .......................................... 40C to 150C LTC3803MP ....................................... 55C to 150C Storage Temperature Range ...................65C to 150C Lead Temperature (Soldering, 10 sec) .................. 300C *LTC3803 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 PBF LTC3803ES6 TRPBF LTACV 6-Lead Plastic TSOT-23 40C to 125C LTC3803IS6 PBF LTC3803IS6 TRPBF LTBNC 6-Lead Plastic TSOT-23 40C to 125C LTC3803HS6 PBF LTC3803HS6 TRPBF LTBNC 6-Lead Plastic TSOT-23 40C to 150C LTC3803MPS6 PBF LTC3803MPS6 TRPBF LTBNC 6-Lead Plastic TSOT-23 55C to 150C LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3803ES6 LTC3803ES6 TR LTACV 6-Lead Plastic TSOT-23 40C to 125C LTC3803IS6 LTC3803IS6 TR LTBNC 6-Lead Plastic TSOT-23 40C to 125C LTC3803HS6 LTC3803HS6 TR LTBNC 6-Lead Plastic TSOT-23 40C to 150C LTC3803MPS6 LTC3803MPS6 TR LTBNC 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. For more information on lead free part marking, go to: