The MAX5042/MAX5043 isolated multimode PWM power ICs feature integrated switching power MOSFETs connected in a voltage-clamped, two-transistor, power-circuit configuration. These devices operate from a wide 20V to 76V input voltage range. The MAX5042 includes a hotswap controller for use with an external power MOSFET to limit inrush current for applications where the power supply is plugged into a live power backplane. The MAX5043 does not include a hot-swap controller. The voltage-clamped power topology of the MAX5042/MAX5043 enables full recovery of stored magnetizing and leakage inductive energy for enhanced efficiency and reliability. Operating at up to 500kHz switching frequency, these devices provide up to 50W of output power. The MAX5042/MAX5043 allow the implementation of both forward and flyback voltage or current-mode converter topologies. A dedicated latched external shutdown provides protection in addition to internal thermal shutdown. The MAX5042/MAX5043 achieve higher efficiency when used with secondary-side synchronous rectification. These devices generate a look-ahead signal for driving secondary-side synchronous rectifiers. The MAX5042/MAX5043 are rated for operation over the -40°C to +125°C and -40°C to +85°C temperature range, respectively, and are available in a small surfacemount 56-pin thin QFN package. Warning: The MAX5042/MAX5043 are designed to work with high voltages. Exercise caution. Applications * Distributed Power Systems with 48V Bus * High-Efficiency Telecom/Datacom Power Supplies * Power-Supply Modules * Router/Switch Cards with 48V Backplane Power Systems * Servers with 48V Backplane Power Systems * xDSL Line Cards * xDSL Line-Driver Power Supplies * Reliable Single-Stage Clamped Two-Switch Power ICs for High Efficiency * No Reset Winding Required * Up to 50W Output Power * Integrated High-Voltage 75mΩ Power MOSFETs * 20V to 76V Wide Input Voltage Range * Feed-Forward Voltage or Current-Mode Control * Programmable Brownout Undervoltage Lockout * Integrated Current Signal Amplifier for High-Efficiency, Current-Mode Control * Internal Overtemperature Shutdown * Indefinite Short-Circuit Protection * Integrated Thermally Protected High-Voltage Startup Linear Regulator * Integrated Hot-Swap Controller (MAX5042) * Integrated Look-Ahead Signal Output Drives High-Speed Optocoupler for Secondary-Side Synchronous Rectification * >90% Efficiency with Synchronous Rectification * Up to 500kHz Switching Frequency * High-Power, Small-Footprint 56-Pin Thermally Enhanced QFN Package