Single IEEE 802.3af Compliant PSE Controller with Internal Switch Features: IEEE 802.3af Compliant Operation from a Single 48V Supply Fully Autonomous Operation without Microcontroller Internal MOSFET with Thermal Protection Power Management Works Across Multiple Ports with Simple RC Network Precision Inrush Control with Internal Sense Resistor Powered Device (PD) Detection and Classification AC and DC Disconnect Sensing Robust Short-Circuit Protection Pin-Selectable Detection Back-off for Midspan PSEs Classification Dependent ICUT Current Threshold LED Driver Indicates Port On and Blinks Status Codes Available in 14-Pin SO and 4mm × 3mm DFN Packages

Quad IEEE 802.3at Power Over Ethernet Controller Features: Four Independent PSE Channels Compliant with IEEE 802.3at Type 1 and 2 0.34Ω Total Channel Resistance 130mW/Port at 600mA Advanced Power Management 8-Bit Programmable Current Limit (ILIM) 7-Bit Programmable Overload Currents (ICUT) Fast Shutdown of Preselected Ports 14.5-Bit Port Current/Voltage Monitoring 2-Event Classification Very High Reliability 4-Point PD Detection 2-Point Forced Voltage 2-Point Forced Current High Capacitance Legacy Device Detection LTC4259A-1 and LTC4258 Pin and SW Compatible 1MHz I2C Compatible Serial Control Interface Midspan Backoff Timer Supports Proprietary Power Levels Above 25W Available in 38-Pin 5mm × 7mm QFN and 36-Pin SSOP Packages

Power over Ethernet IEEE 802.3af PD Interface with Integrated Switching Regulator Features: Complete Power Interface Port for IEEE 802®.3af Powered Device (PD) Onboard 100V, 400mA UVLO Switch Precision Dual Level Inrush Current Limit Integrated Current Mode Switching Regulator Onboard 25kΩ Signature Resistor with Disable Programmable Classication Current (Class 0-4) Thermal Overload Protection Power Good Signal Integrated Error Amplier and Voltage Reference Low Prole 16-Pin SSOP and 3mm × 5mm DFN Packages

Power over Ethernet IEEE 802.3af PD Interface with Integrated Switching Regulator Features: Complete Power Interface Port for IEEE 802®.3af Powered Device (PD) Onboard 100V, 400mA UVLO Switch Precision Dual Level Inrush Current Limit Integrated Current Mode Switching Regulator Onboard 25kΩ Signature Resistor with Disable Programmable Classication Current (Class 0-4) Thermal Overload Protection Power Good Signal Integrated Error Amplier and Voltage Reference Low Prole 16-Pin SSOP and 3mm × 5mm DFN Packages

Single PoE+ PSE Controller Features: Compliant with IEEE 802.3at Type 1 and 2 0.34Ω Total Channel Resistance 130mW/Port at 600mA Advanced Power Management 8-Bit Programmable Current Limit (ILIM) 7-Bit Programmable Overload Currents (ICUT) Fast Shutdown 14.5-Bit Port Current/Voltage Monitoring 2-Event Classification Very High Reliability 4-Point PD Detection 2-Point Forced Voltage 2-Point Forced Current High Capacitance Legacy Device Detection LTC4259A-1 and LTC4266 SW Compatible 1MHz I2C Compatible Serial Control Interface Midspan Backoff Timer Supports Proprietary Power Levels Above 25W Available in 38-Pin 5mm × 7mm QFN Package

4-Port IEEE 802.3bt PoE PSE Controller Features: Four PSE Ports Two Power Channels per Port Low Power Path Dissipation per Channel 150mΩ Sense Resistance 30mΩ or Lower MOSFET RDS(ON) Chipset Provides Electrical Isolation Eliminates Optos and Isolated 3.3V Supply Very High Reliability Multipoint PD Detection Connection Check Distinguishes Single-Signature and Dual-Signature PDs Fully Compliant IEEE 802.3bt Type 3 and 4 PSE Compliant Support for Type 1, 2, 3, and 4 PDs Continuous, Dedicated Per-Port Power and Current Monitoring Per-Port Power Policing 1MHz I2C Compatible Serial Control Interface Pin or I2C Programmable PD Power Up to 71.3W Available in a 40-Lead 6mm × 6mm (LTC4292) and 24-Lead 4mm × 4mm (LTC4291-1) QFN Packages

2-Wire Bus Buffers with High Noise Margin Features:Bidirectional Buffer Increases FanoutHigh Noise Margin with VIL = 0.3•VCCCompatible with Non-Compliant I2C Devices That Drive a High VOLStrong (LTC4313-1) and 2.5mA (LTC4313-2) Rise Time Accelerator CurrentLevel Shift 1.5V, 1.8V, 2.5V, 3.3V and 5V BussesPrevents SDA and SCL Corruption During Live Board Insertion and Removal from BackplaneStuck Bus Disconnect and RecoveryCompatible with I2C, I2C Fast Mode and SMBus±4kV Human Body Model ESD RuggednessHigh Impedance SDA, SCL Pins When Unpowered8-Lead MSOP and 8-Lead (3mm × 3mm) DFN Packages

Low Quiescent Current eFuse with Surge Protection Features: Withstands Surge Voltages Up to 100V Internal 9mΩ N-Channel MOSFET Guaranteed Safe Operating Area: 20ms at 70V, 1A Low Quiescent Current: 6μA Operating Operates Through Automobile Cold Crank Wide Operating Voltage Range: 4V to 72V No Input TVS Needed Overcurrent Protection Selectable Internal 28.5V/47V or Adjustable Output Clamp Voltage Reverse Input Protection to –60V Adjustable Turn-On Threshold Adjustable Fault Timer with MOSFET Stress Acceleration Latchoff and Retry Options Low Retry Duty Cycle During Faults 32-Lead DFN (7mm × 5mm) Package

Low Quiescent Current eFuse with Surge Protection Features: Withstands Surge Voltages Up to 100V Internal 9mΩ N-Channel MOSFET Guaranteed Safe Operating Area: 20ms at 70V, 1A Low Quiescent Current: 6μA Operating Operates Through Automobile Cold Crank Wide Operating Voltage Range: 4V to 72V No Input TVS Needed Overcurrent Protection Selectable Internal 28.5V/47V or Adjustable Output Clamp Voltage Reverse Input Protection to –60V Adjustable Turn-On Threshold Adjustable Fault Timer with MOSFET Stress Acceleration Latchoff and Retry Options Low Retry Duty Cycle During Faults 32-Lead DFN (7mm × 5mm) Package

Prioritized PowerPath Controller Features:Selects Highest Priority Supply from Three InputsBlocks Reverse and Cross Conduction CurrentsWide Operating Voltage Range: 2.5V to 36V–42V Protection Against Reverse Battery ConnectionFast Switchover Minimizes Output Voltage DroopLow 28μA Operating Current<1μA Current Draw from Supplies Less than VOUT1.5% Input Overvoltage/Undervoltage ProtectionAdjustable Overvoltage/Undervoltage HysteresisP-Channel MOSFET Gate Protection ClampCascadable for Additional Input Supplies24-Lead Narrow SSOP and 4mm × 4mm QFN Packages