MAX5984 MAXIM [Maxim Integrated Products], MAX5984 Datasheet - Page 13

• Manufacturer Part Number: MAX5984
• Description: Single-Port, 40W, IEEE 802.3af/at PSE Controller with Integrated MOSFET
• Manufacturer: MAXIM [Maxim Integrated Products]

The MAX5984 is a single-port, PSE power controller
designed for use in IEEE 802.3af/IEEE 802.3at-compliant
PSE. This device provides PD discovery, classification,
current limit, and DC and AC load-disconnect detec-
tions. The MAX5984 operates automatically without the
need for any software programming and features an inte-
grated 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
MAX5984 provides up to 40W to a single port (Class 5
enabled) and still provides high-capacitance detection
for legacy PDs.
MIDSPAN
LEGACY
AGND
LED
V
EN
EE
Single-Port, 40W, IEEE 802.3af/802.3at PSE
BIAS AND
MONITOR
REGISTER FILE
ANALOG
SUPPLY
______________________________________________________________________________________
Detailed Description
CENTRAL LOGIC
UNIT (CLU)
INTERNAL
SUPPLIES
VOLTAGE
REFERENCES
CURRENT
REFERENCES
2-EVENT/PWMEN/LSCEN
Controller with Integrated MOSFET
MACHINE (SM)
PORT STATE
OSC STATUS
MONITOR
2-EVENT/PWMEN/LSCEN
OSC
AC DISCONNECT
SIGNAL (ACD)
GENERATOR
TRIANGLE
WAVE
MAX5984
The MAX5984 provides input UVLO, input overvoltage
lockout, overtemperature detection, output voltage slew-
rate limit during startup, and LED status indication.
The MAX5984 is reset by any of the following conditions:
1) Power-up. Reset condition is cleared once V
2) Hardware reset. Reset occurs once the EN input is
3) Thermal shutdown. The device enters thermal shut-
CLASSIFICATION
DETECTION AND
CURRENT-LIMIT
above the UVLO threshold.
driven low (> 40µs typ) any time after power-up. The
device exits the reset condition once the EN input is
driven high again.
down at +150NC. The device exits thermal shutdown
and is reset once the temperature drops below 130NC.
PROBING AND
CONTROL
VOLTAGE
CONTROL
THRESHOLD
SETTINGS
AC DETECTOR
A = 1
ACD
REFERENCE
CURRENT
OVERCURRENT, AND OPEN-
CLASS 5 ENABLE/DISABLE,
AND FOLDBACK CONTROL
CURRENT LIMIT CONTROL
OVERCURRENT AND
CIRCUIT SENSING,
9-BIT ADC
CURRENT LIMIT,
AC DISCONNECT
ILIM1
CURRENT SENSING
DRIVE
GATE
ENABLE
Simplified Diagram
ILIM2
VOLTAGE
SENSING
FOLDBACK
CONTROL
INTERNAL
INTERNAL
MOSFET
R
SENSE
AGND
EE
Reset
DET
OUTP
OUT
rises
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