LTC3806EDE#PBF Analog Devices

LTC3806 Synchronous Flyback DC/DC Controller FEATURES DESCRIPTIO High Efficiency at Full Load The LTC 3806 is a current mode synchronous flyback Better Cross Regulation Than Nonsynchronous controller that drives N-channel power MOSFETs and Converters (Multiple Outputs) requires very few external components. It is intended for Soft-Start Minimizes Inrush Current medium power applications where multiple outputs are Current Mode Control Provides Excellent required. Synchronous rectification provides higher effi- Transient Response ciency and improved output cross regulation than High Maximum Duty Cycle: 89% Typical nonsynchronous converters. 2% Programmable Undervoltage Lockout Threshold The IC contains all the necessary control circuitry includ- 1% Internal Voltage Reference ing a 250kHz oscillator, precision undervoltage lockout Micropower Start-Up circuit with hysteresis, gate drivers for primary and syn- Constant Frequency Operation (Never Audible) chronous switches, current mode control circuitry and 3mm 4mm 12-Pin DFN Package soft-start circuitry. U Programmable soft-start reduces inrush currents. This APPLICATIO S makes it easier to design compliant Power Over Ethernet supplies. 48V Telecom Supplies 12V/42V Automotive Low start-up current reduces power dissipation in the 24V Industrial start-up resistor and reduces the size of the external start- VoIP Phone up capacitor. Power Over Ethernet The LTC3806 is available in a 12-pin, exposed pad DFN package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIO V OUT1 V IN 3.3V 36V TO 72V V OUT2 3A C7 D1 T1 2.5V 4.7F 3A R1 R2 51k 604k LTC3806 RUN SENSE I SS R8 TH 100 FB G2 V G1 M1 M2 M3 IN C1 C2 INTV GND CC 100F 1nF R3 R4 C3 C4 R5 C5 C6 26.7k 3.4k 4.7F 0.47F 0.056 470F 470F 3806 F01 R7 R6 12.4k 21k Figure 1. Multiple Output Flyback Converter for Telecom 3806fb 1 U ULTC3806 PI CO FIGURATIO ABSOLUTE MAXIMUM RATINGS (Note 1) TOP VIEW V Voltage ............................................................. 25V IN INTV Voltage ......................................................... 8V RUN 1 12 SENSE CC INTV Output Current ........................................ 50mA I 2 11 NC TH CC FB 3 10 SS G1, G2 Voltages ....................... 0.3V to V + 0.3V INTVCC 13 NC 4 9 G1 I , FB, SS Voltages .................................0.3V to 2.7V TH V 5 8 G2 IN RUN Voltage ............................................... 0.3V to 7V INTV 6 7 GND CC SENSE Pin Voltage ..................................... 0.3V to 8V Operating Ambient Temperature Range DE12 PACKAGE 12-LEAD (4mm 3mm) PLASTIC DFN (Note 2) .................................................. 40C to 85C T = 125C, = 34C/W JMAX JA Junction Temperature (Note 3)............................ 125C EXPOSED PAD (PIN 13) IS GND MUST BE SOLDERED TO PCB Storage Temperature Range ................. 65C to 125C UUW ORDER I FOR ATIO LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3806EDE PBF LTC3806EDE TRPBF 3806 12-Lead (4mm 3mm) Plastic DFN 40C to 85C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: