MAX5953BUTM+T

MAX5953BUTM+T Features

InterfacePD Detection and Programmable ClassificationSignaturesLess than 10µA Leakage Current Offset DuringDetectionIntegrated MOSFET for Isolation and InrushCurrent LimitingGate Output Allows External Control of theInternal Isolation MOSFETProgrammable Inrush Current ControlProgrammable Undervoltage Lockout(MAX5953A/MAX5953C)♦ DC-DC ConverterClamped, Two-Switch Power IC for HighEfficiencyIntegrated High-Voltage 0.4Ω Power MOSFETsUp to 15W Output PowerBias Voltage Regulator with Automatic High-Voltage Supply Turn-Off11V to 76V Wide Input Voltage RangeFeed-Forward Voltage-Mode Control for FastInput Transient RejectionProgrammable Undervoltage LockoutOvertemperature ShutdownIndefinite Short-Circuit Protection withProgrammable Fault IntegrationIntegrated Look-Ahead Signal for Secondary-Side Synchronous Rectification> 90% Efficiency with SynchronousRectificationUp to 500kHz Switching Frequency♦ High-Power (2.22W), 7mm x 7mm ThermallyEnhanced Lead-Free Thin QFN Package

MAX5953BUTM+T General Description

The MAX5953A/MAX5953B/MAX5953C/MAX5953Dintegrate a complete power IC solution for PoweredDevices (PD) in a Power-Over-Ethernet (PoE) system, incompliance with the IEEE 802.3af standard. TheMAX5953A/MAX5953B/MAX5953C/MAX5953D providethe PD with a detection signature, a classification sig-nature, and an integrated isolation switch with program-mable inrush current control. These devices alsointegrate a voltage-mode PWM controller with twopower MOSFETs connected in a two-switch voltage-clamped DC-DC converter configuration.An integrated MOSFET provides PD isolation duringdetection and classification. All devices guarantee aleakage current offset of less than 10µA during thedetection phase. A programmable current limit pre-vents high inrush current during power-on. The devicesfeature power-mode undervoltage lockout (UVLO) withwide hysteresis and long deglitch time to compensatefor twisted-pair-cable resistive drop and to assureglitch-free transition between detection, classification,and power-on/-off phases. The MAX5953A/MAX5953Chave an adjustable UVLO threshold with the defaultvalue compliant to the 802.3af standard, while theMAX5953B/MAX5953D have a lower and fixed UVLOthreshold compatible with some legacy pre-802.3afpower-sourcing equipment (PSE) devices.The DC-DC converters are operable in either forward orflyback configurations with a wide input voltage rangefrom 11V to 76V and up to 15W of output power. Thevoltage-clamped power topology enables full recoveryof stored magnetizing and leakage inductive energy forenhanced efficiency and reliability. When using thehigh-side MOSFET, the controller can be configured asa buck converter. A look-ahead signal for driving sec-ondary-side synchronous rectifiers can be used toincrease efficiency. A wide array of protection featuresinclude UVLO, over-temperature shutdown, and short-circuit protection with hiccup current limit for enhancedperformance and reliability. Operation up to 500kHzallows for smaller external magnetics and capacitors.The MAX5953A/MAX5953B/MAX5953C/MAX5953D areavailable in a high-power (2.22W), 7mm x 7mm ther-mally enhanced thin QFN package.♦ Powered Device InterfaceFully Integrated IEEE 802.3af-Compliant PD

MAX5953BUTM+T Applications

IEEE 802.3af PoweredDevicesIP PhonesWireless Access NodesInternet AppliancesSecurity CamerasComputer TelephonyFor pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.