The MAX5945 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 MAX5945 can be used
in either endpoint PSE (LAN switches/routers) or midspan
PSE (power injector) applications.
The MAX5945 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
MAX5945 is a slave device. Its four address inputs
allow 16 unique MAX5945 addresses. A separate active-low INT
output and four independent shutdown inputs (active-low SHD_)
allow fast response from a fault to port shutdown. An
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 MAX5945 to be used
in midspan systems.
The MAX5945 is fully software configurable and programmable.
A class-overcurrent 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 MAX5945'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 MAX5945 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.
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