The LTC4290/LTC4271 isolated eight-port power source equipment (PSE) controller chipset suits IEEE 802.3at (PoE+) Type 1- and Type 2-compliant PoE systems. The LTC4271 provides a digital interface to the PSE host, and the LTC4290 provides the high-voltage Ethernet interface. The two ICs are bridged by an Ethernet transformer. The transformer-isolated communication protocol replaces up to six optocouplers and an isolated 3.3-V supply.
The PSE controller uses a proprietary dual-mode, four-point detection mechanism that ensures optimum immunity from false PD detection. The controller uses power management techniques that include prioritized fast shutdown, a 12-bit/port voltage and current readback, an 8-bit programmable current limits, and 7-bit programmable overload current limits, and field-upgradeable firmware. An I2 C interface allows a host controller to digitally configure the IC or query port readings. The LTC4290 is offered in three power grades to support power needs from 13 to 90 W. The chipset prices start at $10 each/1,000.
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