Quad IEEE 802.3af Power over Ethernet Controller with AC Disconnect Features: Controls Four Independent – 48V Powered Ethernet Ports Each Port Includes: IEEE 802®.3af Compliant PD Detection and Classification Output Current Limit with Foldback Short-Circuit Protection with Fast Gate Pull-Down PD Disconnect Using AC or DC Sensing Power Good Indication Operates Autonomously or Controlled by I2C™ Serial Interface 4-Bit Programmable Digital Address Allows Control of Up to 64 Ports Programmable INT Pin Eliminates Software Polling Current and Duty Cycle Limits Protect External FETs Available in a 36-Pin SSOP Package

Quad IEEE 802.3af Power over Ethernet Controller with AC Disconnect Features: Controls Four Independent – 48V Powered Ethernet Ports Each LTC4259A-1 Port Includes: – IEEE 802®.3af Compliant PD Detection and Classification – Output Current Limit with Foldback – Short-Circuit Protection with Fast Gate Pull-Down – PD Disconnect Using AC or DC Sensing – Improved AC Disconnect – Improved UVLO Operates Autonomously or Controlled by I2C™ Serial Interface 4-Bit Programmable Digital Address Allows Control of Up to 64 Ports Current and Duty Cycle Limits Protect External FETs IMPROVED UVLO

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

Negative Voltage Diode-OR Controller and Monitor Features: Controls N-Channel MOSFETs Replaces Power Schottky Diodes Less Than 1µs Turn-off Time Limits Peak Fault Current 80V Operation Smooth Switchover Without Oscillation No Reverse DC Current Fault Output Selectable Fault Thresholds Available in 8-Pin (3mm × 2mm) DFN and 8-Pin SO Packages

Positive High Voltage Ideal Diode-OR with Input Supply and Fuse Monitors Features: Replaces Power Schottky Diodes Controls N-Channel MOSFETs 0.3μs Turn-Off Time Limits Peak Fault Current Wide Operating Voltage Range: 9V to 80V Smooth Switchover without Oscillation No Reverse DC Current Monitors VIN, Fuse, and MOSFET Diode Available in 14-Lead (4mm × 3mm) DFN, 16-Lead MS and SO Packages