DESCRIPTION
The LTC®9101-2 chipset is a 12/24-port power sourcing
equipment (PSE) controller designed for use in IEEE 802.3bt
Type 3 and 4 compliant Power over Ethernet (PoE) systems.
The LTC9101-2/LTC9102 is designed to power compliant
802.3af, 802.3at, and 802.3bt PDs. The LTC9101-2/LTC9102
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/voltage monitoring, programmable 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 LTC9101-2/LTC9102 includes an
I2C serial interface operable up to 1MHz. The LTC9101-2/
LTC9102 is pin or I2C programmable to negotiate PD delivered
power up to 71.3W.

FEATURES
- Fully Compliant IEEE 802.3bt Type 3 and 4 PSE
- Up to 24 PSE Ports with Two Power Channels per Port
- +80V/–20V Tolerant Port-Facing Pins
- ECC-Protected eFlash and Data RAMs
- Low Power Path Dissipation per Channel
- 100mΩ Sense Resistance
- 30mΩ or Lower MOSFET RDS(ON)
- Chipset Provides Electrical Isolation
- Eliminates Optos and Isolated 3.3V Supply
- Very High Reliability Multipoint PD Detection
- Connection Check Distinguishes Single-
Signature and Dual-Signature PDs
- Continuous Per-Port Voltage and Current Monitoring
- 1MHz I2C Compatible Serial Control Interface
- Pin or I2C Programmable PD Power
- Available in a 24-Lead 4mm × 4mm (LTC9101‑2) and
64-Lead 7mm × 11mm (LTC9102) QFN Packages

APPLICATIONS
- PoE PSE Switches/Routers and Midspans