General DescriptionThe MAX5971A is a single-port, power-sourcing equipment (PSE) power controller designed for use in IEEE® 802.3af/at-compliant PSE. This device provides powered device (PD) discovery, classification, current limit, and DC and AC load-disconnect detections. The MAX5971A operates automatically without the need for any software programming and features an integrated power MOSFET and sense resistor. The device also supports new Class 5 and 2-event classification for detection and classification of high-power PDs. The MAX5971A provides up to 40W to a single port (Class 5 enabled) and still provides highcapacitance detection for legacy PDs.

Features♦ IEEE 802.3af/at Compliant
♦ Up to 40W for Single-Port PSE Applications
♦ Integrated 0.5I Power MOSFET and Sense Resistor
♦ PD Detection and Classification
♦ Programmable Current Limit for Class 5 PDs
♦ High-Capacitance Detection for Legacy Devices
♦ Supports Both DC and AC Load Removal Detections
♦ Current Foldback and Duty Cycle-Controlled Current Limit
♦ LED Indicator for Port Status
♦ Direct Fast-Shutdown Control Capability
♦ Space-Saving, 28-Pin TQFN (5mm x 5mm) Package

Applications Single-Port PSE End-Point Applications
Single-Port PSE Power Injectors (Midspan Applications)
Switches/Routers
Industrial Automation Equipment
Wireless LAN Access Point/WiMAX™ Base Station

Manufacturer	Maxim Integrated
Product Category	AC DC Converters, Offline Switchers
Series	MAX5975
Packaging	Tube Alternate Packaging
Package-Case	16-WFQFN Exposed Pad
Operating-Temperature	-40°C ~ 150°C (TJ)
Mounting-Type	Surface Mount
Supplier-Device-Package	16-TQFN (3x3)
Watt	-
Output-Isolation	Either
Internal-Switch-s	No
Voltage-Breakdown	-
Topology	Flyback, Forward
Voltage-Start-Up	20V
Voltage-Supply-Vcc-Vdd	20 V ~ 26 V
Duty-Cycle	82.50%
Frequency-Switching	100kHz ~ 600kHz
Fault-Protection	Over Temperature
Control-Features	EN, Frequency Control, Soft Start, Sync
Part-#-Aliases	MAX5975