MP3908 Current Mode PWM Controller with Synchronous Secondary Gate Drive The Future of Analog IC Technology DESCRIPTION FEATURES The MP3908 is a flexible current-mode PWM Programmable Dead-Time controller optimized for power-supply Synchronous Secondary Gate Drive applications. The MP3908 features resistor- Current Mode Control programmable dead-time control to optimize 10V MOSFET Gate Drivers efficiency for a broad number of different Drives >10A MOSFETs configurations, and a synchronous secondary Soft-Start gate drive. The MOSFET drivers are capable Cycle-by-Cycle Current Limiting of driving >10A MOSFETs. It has an operational Slope Current Compensation current of typically 270A and can accommodate Lossless Current Sense (V <28V) ISENSE off-line, Telecom and non-isolated applications. 50A Shutdown Current Under-voltage lockout, soft-start, slope 270uA typical Operating Current compensation and peak current limiting are all 250KHz Constant Frequency Operation included. In a boost application, with an output Applicable to Boost, SEPIC, Flyback and voltage of less than 28V, the current sense pin Forward Topologies can connect directly to the drain of the external Available in a 10-Pin MSOP Package switch. This eliminates the requirement for an additional current sensing element and its APPLICATIONS associated efficiency loss. PoE PD Power Supplies While designed for boost applications, the MP3908 TV CCFL Power Generation can also be used for other topologies including Telecom Isolated Power Forward, Flyback and Sepic. The 10V gate driver Brick Modules compliance minimizes the power loss of the external Off-line Controller MOSFET while allowing the use of a wide variety of standard threshold devices. An externally MPS and The Future of Analog IC Technology are Registered Trademarks of Monolithic Power Systems, Inc. programmable delay following the turn off of the synchronous rectifier allows the incorporation of secondary side synchronous rectifier The MP3908 is available in space saving 10-pin MSOP package. TYPICAL APPLICATION Efficiency vs. Output Current 8 95 VCC T1 7 5 GND DELAY 90 ADJ MP3908 85 2 9 EN MAIN 6 80 ISENSE 1 10 CSS SYNC 75 COMP FB 3 4 70 65 60 0123456 OUTPUT CURRENT (A) MP3908 Rev.0.9 www.MonolithicPower.com 1 8/29/2008 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. 2008 MPS. All Rights Reserved. EFFICIENCY (%)MP3908 HIGH EFFICIENCY BOOST CONTROLLER (1) PACKAGE REFERENCE ABSOLUTE MAXIMUM RATINGS VCC .............................................0.3V to +10V VCC Maximum Current ............................ 30mA TOP VIEW ISENSE .......................................0.3V to +28V FB ..............................................0.3V to +1.3V 1 10 COMP............................................0.3V to +3V 2 9 CSS, ENABLE ...............................0.3V to +5V 3 8 Junction Temperature...............................125C Lead Temperature ....................................260C 4 7 Storage Temperature ..............65C to +150C 5 6 (2) Recommended Operating Conditions VCC Current ................................. 1mA to 25mA Operating Temperature .............40 C to +85 C (3) Thermal Resistance JA JC Part Number* Package Temperature MSOP10 ................................ 150..... 65... C/W MP3908DK MSOP10 40 C to +85C For Tape & Reel, add suffix Z (eg. MP3908DKZ) * Notes: For RoHS compliant packaging, add suffix LF (eg. 1) Exceeding these ratings may damage the device. MP3908DKLFZ) 2) The device is not guaranteed to function outside of its operating conditions. 3) Measured on approximately 1 square of 1 oz copper. ELECTRICAL CHARACTERISTICS V = 10V, T = +25 C, unless otherwise noted. CC A Parameter SymbolCondition Min Typ Max Units VCC Undervoltage Lockout Internal Divider (I) 4.5 4.7 V Q VCC On/Off Voltage Hysteresis 1 V Shutdown Current I EN/SS = 0V, V = 9V 50 A S IN Output not switching, V = FB Quiescent Current (Operation) I 270 320 A Q 1V, V = 9V CC Main Gate Driver Impedance V = 9V, V = 5V 16 CC GATE (Sourcing) Main Gate Driver Impedance V = 9V, I = 5mA 5.0 CC GATE (Sinking) Synchronous Gate Driver V = 9V, V = 5V 16 CC SYNCGATE Impedance (Sourcing) Synchronous Gate Driver V = 9V, I = 5mA 5.0 CC GATE Impedance (Sinking) Delay after Synchronous Gate R =100k 50 ns DELAY V connected to V FB COMP/RUN. Error Amplifier Transconductance 0.26 0.38 0.46 mA/V Force 10A to V . COMP/RUN Maximum Comp Current Sourcing and Sinking 40 A (4) Error Amplifier Translator Gain A 0.28 0.32 0.36 V/V ET Switching Frequency f 220 260 300 KHz S Thermal Shutdown 150 C Maximum Duty Cycle 76 81 86 % Minimum On Time t 200 ns ON ISENSE Limit 165 190 215 mV FB Voltage V 0.794 0.818 0.847 V FB FB Bias Current I Current flowing out of part 50 nA FB Note: 4) Guaranteed by design. MP3908 Rev.0.9 www.MonolithicPower.com 2 8/29/2008 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. 2008 MPS. All Rights Reserved.