MAX5945 Datasheet, PDF (12/44 Pages) Maxim Integrated Products – Quad Network Power Controller for Power-Over-LAN

Quad Network Power Controller
for Power-Over-LAN
A0
A1
A2
A3
AUTO
MIDSPAN
RESET
INT
AGND
VEE
VDD SCL SDAIN SDAOUT
SHD_
OSC_IN DGND
SERIAL
PORT
INTERFACE
(SPI)
OSCILLATOR
MONITOR
VOLTAGE PROBING
AND
CURRENT-LIMIT
CONTROL
CURRENT SENSING
DET_
REGISTER FILE
PORT
STATE
MACHINE
(SM)
DETECTION/
CLASSIFICATION
SM
ACD_ENABLE
A=3
9-BIT ADC
CONVERTER
VOLTAGE
SENSING
10V
50µA
OUT_
GATE_
CENTRAL LOGIC UNIT
(CLU)
AC DISCONNECT
SIGNAL
(ACD)
PWR_EN
AC
DETECTION
ACD
REFERENCE
CURRENT
FAST
DISCHARGE
CONTROL
100mA _90µA
MAX
13V CLAMP
SENSE_
ANALOG
BIAS/
SUPPLY
MONITOR
+10V ANALOG
+5V DIG
VOLTAGE
REFERENCES
CURRENT
REFERENCES
OPEN CIRCUIT
(OC)
CURRENT
LIMIT (ILIM)
CURRENT-LIMIT
DETECTOR
MAX5945
OVERCURRENT
(OVC)
4mV
182mV
212mV
FOLDBACK
CONTROL
Figure 1. MAX5945 Functional Diagram
Detailed Description
The MAX5945 four-port network power controller con-
trols -32V to -60V negative supply rail systems. Use the
MAX5945, which is compliant with the IEEE 802.3af
standard for PSE in power-over-LAN applications. The
MAX5945 provides PD discovery, classification, current
limit, both DC and AC load disconnect detections, and
other necessary functions for an IEEE 802.3af-compli-
ant PSE. The MAX5945 can be used in either endpoint
PSE (LAN switch/router) or midspan PSE (power injec-
tor) applications.
The MAX5945 is fully software-configurable and pro-
grammable with more than 25 internal registers. The
device features an I²C-compatible, 3-wire serial inter-
face and a class-overcurrent detection. The class-over-
current detection function enables system power man-
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