LT3798 Isolated No Opto-Coupler Flyback Controller with Active PFC FEATURES DESCRIPTION n Isolated PFC Flyback with Minimum Number of The LT 3798 is a constant-voltage/constant-current iso- External Components lated flyback controller that combines active power factor n V and V Limited Only by External Components correction (PFC) with no opto-coupler required for output IN OUT n Active Power Factor Correction voltage feedback into a single-stage converter. A LT3798 n Low Harmonic Distortion based design can achieve a power factor of greater than 0.97 n No Opto-Coupler Required by actively modulating the input current, allowing compli- n Constant-Current and Constant-Voltage Regulation ance with most Harmonic Current Emission requirements. n Accurate Regulated Voltage and Current (5% Typical) The LT3798 is well suited for a wide variety of off-line n Energy Star Compliant (<0.5W No Load Operation) applications. The input range can be scaled up or down, n Thermally Enhanced 16-lead MSOP Package depending mainly on the choice of external components. Efficiencies higher than 86% can be achieved with output APPLICATIONS power levels up to 100W. In addition, the LT3798 can easily n Offline 5W to 100W+ Applications be designed into high DC input applications. n High DC V Isolated Applications IN 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 Offline Bus Converter (12V, 24V or 48V Outputs) Protected by U.S. Patents, including 5438499 and 7471522. TYPICAL APPLICATION Universal Input 24W PFC Bus Converter V vs I OUT OUT 24.50 90V TO 265V 24.25 AC 499k 100k D2 20 24.00 4:1:1 0.1F 499k 100k 4.7pF 10F 2k D3 23.75 VAC = 90V VAC = 120V D4 90.9k V DCM IN VAC = 220V 24V 1M V VAC = 265V IN SENSE 1A FB Z1 23.50 EN/UVLO 0 0.2 0.4 0.6 0.8 1 560F 4.99k 22pF 95.3k I (A) OUT 2 D1 LT3798 3798 TA01b V REF 20 Z2 100k 40.2k CTRL3 GATE CTRL2 SENSE INTV CTRL1 CC 0.05 OVP 4.7F 2.2nF GND 221k 16.5k + V COMP COMP C 0.1F 2.2F 3798 TA01a 3798fa 1 V (V) OUTLT3798 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW EN/UVLO ...................................................................30V 1 V CTRL1 16 IN SENSE CTRL2 2 15 SENSE V ............................................................................42V IN 3 CTRL3 14 GATE V 17 INTV ......................................................................12V 4 13 INTV REF CC CC 5 GND OVP 12 EN/UVLO CTRL1, CTRL2, CTRL3 ................................................4V V 6 11 V C IN + 7 + COMP 10 DCM FB, V , COMP ........................................................3V REF COMP 8 9 FB V , OVP, COMP .........................................................4V MSE PACKAGE C 16-LEAD PLASTIC MSOP SENSE ......................................................................0.4V = 50C/W, = 10C/W JA JC V .................................................................1mA EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB IN SENSE DCM .......................................................................3mA Operating Temperature Range (Note 2) LT3798E/LT3798I................................... 40C to 125C Storage Temperature Range .................. 65C to 150C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3798EMSE PBF LT3798EMSE TRPBF 3798 16-Lead Plastic MSOP 40C to 125C LT3798IMSE PBF LT3798IMSE TRPBF 3798 16-Lead Plastic MSOP 40C to 125C LT3798HMSE PBF LT3798HMSE TRPBF 3798 16-Lead Plastic MSOP 40C to 150C LT3798MPMSE PBF LT3798MPMSE TRPBF 3798 16-Lead Plastic MSOP 55C 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. For more information on lead free part marking, go to: