The LTC9101-1 from Analog Devices is a 48-Port IEEE 802.3bt PoE PSE Controller that has been designed for use in IEEE 802.3at Type 2, 802.3bt Type 3, and 4 compliant Power over Ethernet (PoE) systems. It requires an input voltage of 51 - 57 V. This controller integrates MOSFETs, transformers, diodes, and other discrete components such as capacitors and resistors. It is built to be power-compliant with 802.3af, 802.3at, and 802.3bt Power Delivery (PD) devices and delivers the lowest-in-industry heat dissipation by utilizing low drain-source on-resistance external MOSFETs along with a 0.1 Ω sensing resistor per power channel. This controller has a transformer-based isolation communication protocol that replaces expensive optocouplers and complex isolated 3.3 V power supplies, thereby significantly saving Bill of Materials (BOM) costs.

The LTC9101-1 is equipped with advanced power management capabilities such as per-port 14-bit current and power monitoring, programmable current and power limits, versatile fast shut-down of preselected ports, and a host software layer. This PSE controller supports PD detection that uses a proprietary multipoint detection mechanism, ensuring excellent immunity against false PD identification. It includes an I²C serial interface operable up to 1 MHz and is I²C programmable to negotiate PD-delivered power up to 71.3 W. This controller IC is available in a surface-mount package that measures 4 x 4 mm and is ideal for PoE PSE switches/routers and midspans applications.