MAX5051AUI+

19-2964; Rev 0; 8/03 KIT ATION EVALU E L B AVAILA Parallelable, Clamped Two-Switch Power-Supply Controller IC The MAX5051 power-supply controller is primary as well as secondary-side parallelable, allowing the design of scaleable power systems when necessary. When paralleling the primary side, dedicated pins allow for simultaneous wakeup or shutdown of all paralleled units, thus preventing current-hogging during startup or fault conditions. The MAX5051 generates a lookahead signal for driving secondary-side synchronous MOSFETs. Special primary-side synchronization inputs/outputs allow two primaries to be operated 180° out of phase for increased output power and lower input ripple currents. The MAX5051 is available in a 28-pin TSSOP-EP package and operates over a wide -40°C to +125°C temperature range. Warning: The MAX5051 is designed to work with high voltages. Exercise caution. Features ♦ Wide Input Voltage Range, 11V to 76V ♦ Voltage Mode with Input Voltage Feed-Forward ♦ Ripple-Phased Parallel Topology for High Current/Power Output ♦ 2A Integrated High- and Low-Side MOSFET Drivers ♦ SYNCIN And SYNCOUT Pins Enable 180° Out-OfPhase Operation ♦ Programmable Brownout and Bootstrap UVLOs ♦ High-Side Driver Bootstrap Capacitor Precharge Driver ♦ Low Current-Limit Threshold for High Efficiency ♦ Programmable Switching Frequency ♦ Reference Voltage Soft-Start for Startup Without Overshoots ♦ Startup Synchronization with Multiple Paralleled Primaries ♦ Programmable Integrating Current-Limit Fault Protection ♦ Look-Ahead PWM Signal for Secondary-Side Synchronous Rectifier Drivers ♦ Look-Ahead Drivers for Either A High-Speed Optocoupler or Pulse Transformer ♦ Wide -40°C to +125°C Operating Range ♦ Thermally Enhanced 28-Pin TSSOP Package Applications High-Efficiency, Isolated Telecom/Datacom Power Supplies 48V and 12V Server Power Supplies 48V Power-Supply Modules 42V Automotive Power Systems Industrial Power Supplies Ordering Information PART MAX5051AUI TEMP RANGE -40°C to +125°C PIN-PACKAGE 28-TSSOP-EP* *EP = Exposed pad. Pin Configuration appears at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX5051 General Description The MAX5051 is a clamped, two-switch power-supply controller IC. This device can be used both in forward or flyback configurations with input voltage ranges from 11V to 76V. It provides comprehensive protection mechanisms against possible faults, resulting in very high reliability power supplies. When used in conjunction with secondary-side synchronous rectification, power-supply efficiencies can easily reach 92% for a +3.3V output power supply operated from a 48V bus. The integrated high- and low-side gate drivers provide more than 2A of peak gate-drive current to two external N-channel MOSFETs. Low startup current reduces the power loss across the bootstrap resistor. A feed-forward voltagemode topology provides excellent line rejection while avoiding the pitfalls of traditional current-mode control. MAX5051 Parallelable, Clamped Two-Switch Power-Supply Controller IC ABSOLUTE MAXIMUM RATINGS AVIN, PVIN, XFRMRH to GND................................-0.3V to +80V BST to GND ............................................................-0.3V to +95V BST, DRVH to XFRMRH..........................................-0.3V to +12V REG9, DRVDD, DRVL to GND................................-0.3V to +12V DRVB, LXVDD, LXL, LXH to GND ..........................-0.3V to +12V UVLO, STT, COMP, CON to GND ..........................-0.3V to +12V FLTINT, RCFF to GND ............................................-0.3V to +12V REG5, CS, CSS, FB to GND .....................................-0.3V to +6V STARTUP, SYNCIN to GND......................................-0.3V to +6V SYNCOUT, RCOSC to GND .....................................-0.3V to +6V PGND to GND .......................................................-0.3V to +0.3V LXL, LXH Current Continuous...........................................±50mA DRVL, DRVH Current Continuous...................................±100mA DRVL, DRVH Peak Current ( 75% > 50% OF IOUT(MAX), dl/dt = 5A/µs Figure 12. Output Voltage Response to Step-Change in Load Current ______________________________________________________________________________________ 19 MAX5051 Parallelable, Clamped Two-Switch Power-Supply Controller IC A IOUT 10A/div B IOUT 10A/div VOUT 50mV/div A: 1ms/div B: 20ms/div 2µs/div Figure 13. Output Voltage Ripple At Nominal Input Voltage and Full Load Current (Scope Bandwidth = 20MHz) Pin Configuration Figure 14. Load Current (10A/div) as a Function of Time When the Converter Attempts to Turn On into a 50mΩ Short Circuit Chip Information TRANSISTOR COUNT: 2049 PROCESS: BiCMOS/DMOS TOP VIEW RCOSC 1 28 SYNCIN SYNCOUT 2 27 FLTINT RCFF 3 26 STARTUP CON 4 25 UVLO CSS 5 Exposed Paddle Connected to GND MAX5051 COMP 6 24 GND 23 AVIN FB 7 22 BST REG5 8 21 DRVH REG9 9 20 XFRMRH PVIN 10 19 DRVB STT 11 18 DRVDD LXVDD 12 17 PGND LXH 13 16 DRVL LXL 14 15 CS TSSOP EXPOSED PADDLE IS INTERNALLY CONNECTED TO GND. 20 ______________________________________________________________________________________ Parallelable, Clamped Two-Switch Power-Supply Controller IC TSSOP 4.4mm BODY.EPS Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 21 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX5051 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)