12-Port PoE/PoE+/LTPoE++ PSE Analog Controller

The LTC4270/LTC4271 chipset is a 12-port power sourcing equipment (PSE) controller designed for use in IEEE 802.3at Type 1 and Type 2 (high power) compliant Power over Ethernet (PoE) systems. Transformer-isolated communication protocol replaces expensive opto-couplers and complex isolated 3.3V supply resulting in significant BOM cost savings. The LTC4270/LTC4271 chipset delivers lowest-in-industry heat dissipation by utilizing low-RDS(ON) external MOSFETs and 0.25Ω sense resistors.

Advanced power management features include per-port 12‑bit current monitoring ADCs, DAC-programmable current limit, and versatile fast shut-down of preselected ports. Advanced power management host software is available under a no-cost license. PD discovery uses a proprietary dual-mode 4-point detection mechanism ensuring excellent immunity from false PD detection. Midspan PSEs are supported with 2-event classification and a 2 second backoff timer. The LTC4270/LTC4271 includes an I2C serial interface operable up to 1MHz.

The LTC4270/LTC4271 is available in multiple power grades allowing delivered PD power up to 90W.

APPLICATIONS

* PoE PSE Switches/Routers

* PoE PSE Midspans

* 12 Independent PSE Channels

* Compliant with IEEE 802.3at Type 1 and 2

* Chipset Provides Electrical Isolation

* Reduced BOM Cost

* Eliminates up to 6 High Speed Opto-Couplers

* Eliminates Isolated 3.3V Power Supply

* Low Power Dissipation

* 0.25Ω Sense Resistance Per Channel

* Very High Reliability 4-Point PD Detection

* 2-Point Forced Voltage

* 2-Point Forced Current