The MAX5935 quad network power controller is designed
for use in IEEE 802.3af-compliant power sourcing equipment
(PSE). The device provides power devices (PD) discovery,
classification, current limit, and both DC and AC
load disconnect detections. The MAX5935 can be used
in either endpoint PSE (LAN switches/routers) or midspan
PSE (power injector) applications.
The MAX5935 can operate autonomously or be controlled
by software through an I2C-compatible interface.
Separate input and output data lines (SDAIN and
SDAOUT) allow usage with optocouplers. The
MAX5935 is a slave device. Its four address inputs
allow 16 unique MAX5935 addresses. A separate active-low INT
output and four independent shutdown inputs (active-low SHD_)
allow fast response from a fault to port shutdown. A
active-low RESET input allows hardware reset of the device. A
special Watchdog feature allows the hardware to
gracefully take over control if the software crashes. A
cadence timing feature allows the MAX5935 to be used
in midspan systems.
The MAX5935 is fully software configurable and programmable.
A class-over-current detection function enables
system power management to detect if a PD draws more
current than the allowable amount for its class. Other features
are input under/overvoltage lockout, overtemperature
protection, output voltage slew-rate limit during
startup, power-good, and fault status. The MAX5935's
programmability includes gate charging current, current-limit
threshold, startup timeout, overcurrent timeout,
autorestart duty cycle, PD disconnect AC detection
threshold, and PD disconnect detection timeout.
The MAX5935 is available in a 36-pin SSOP package
and is rated for both extended (-40°C to +85°C) and
commercial (0°C to +70°C) temperature ranges.
Key Features
Applications/Uses
IEEE 802.3af Compliant
Controls Four Independent, -48V-Powered Ethernet Ports in Either Endpoint or Midspan PSE Applications
Wide Digital Power Input, VDIG, Common-Mode Range: VEE to (AGND + 7.7V)
PD Violation of Class Current Protection
PD Detection and Classification
Provides Both DC and AC Load Removal Detections
I²C-Compatible, 3-Wire Serial Interface
Fully Programmable and Configurable Operation Through I²C Interface
Current Foldback and Duty-Cycle-Controlled/Programmable Current Limit
