The LTC9101-1/LTC9102/LTC9103 chipset is a 48-port power sourcing equipment (PSE) controller designed for use in IEEE 802.3at Type 2, 802.3bt Type 3 and 4 compliant Power over Ethernet (PoE) systems. The LTC9101-1/LTC9102/LTC9103 is designed to power compliant 802.3af, 802.3at, and 802.3bt PDs. The LTC9101-1/LTC9102/LTC9103 chipset delivers lowest-in-industry heat dissipation by utilizing low-RDS(ON)external MOSFETs and 0.1Ω sense resistance per power channel. A transformer-isolated communication protocol replaces expensive opto-couplers and complex isolated 3.3V supply, resulting in significant BOM cost savings.Advanced power management features include per-port 14‑bit current/power monitoring, programmable current/power limits, and versatile fast shut-down of preselected ports. An advanced power management host software layer is available. PD detection uses a proprietary multipoint detection mechanism ensuring excellent immunity from false PD identification. Autoclass and 5-event physical classification are supported. The LTC9101-1/LTC9102/LTC9103 includes an I2C serial interface operable up to 1MHz. The LTC9101-1/LTC9102/LTC9103 is pin or I2C programmable to negotiate PD delivered power up to 71.3W.APPLICATIONSPoE PSE Switches/Routers and Midspans