The LTC4263 is an autonomous single-channel PSE controller for use in IEEE 802.3af compliant Power over Ethernet systems. It includes an onboard power MOSFET, internal inrush, current limit, and short-circuit control, IEEE 802.3af compliant PD detection and classification circuitry, and selectable AC or DC disconnect sensing. Onboard control algorithms provide complete IEEE 802.3af compliant operation without the need of a microcontroller. The LTC4263 simplifies PSE implementation, needing only a single 48V supply and a small number of passive support components. Programmable onboard power management circuitry permits multiple LTC4263s to allocate and share power in multi-port systems, allowing maximum utilisation of the 48V power supply-all without the intervention of a host processor. The port current limit can be configured to automatically adjust to the detected PD class. Detection backoff timing is configurable for either Endpoint or Midspan operation. Built-in foldback and thermal protection provide comprehensive fault protection. An LED pin indicates the state of the port controlled by the LTC4263. When run from a single 48V supply, the LED pin can operate as a simple switching current source to reduce power dissipation in the LED drive circuitry. The LTC4263 is available in 14-pin 4mm × 3mm DFN and 14-pin SO packages.
