MAX5980GTJ+T Maxim Integrated, MAX5980GTJ+T Datasheet - Page 15

• Manufacturer Part Number: MAX5980GTJ+T
• Description: Power Switch ICs - POE / LAN 0-16V Hot-Swap Controller
• Manufacturer: Maxim Integrated

Specifications of MAX5980GTJ+T

• Rohs: yes
• Number Of Switches: Quad
• Off Time (max): 0.1 ms
• Operating Supply Voltage: 32 V to 60 V
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• Maximum Power Dissipation: 2758.6 mW
• Minimum Operating Temperature: - 40 C
• Operating Supply Current: 5 mA

The MAX5980 is a quad PSE power controller designed
for use in IEEE 802.3at/af-compliant PSE. This device
provides PD discovery, classification, current limit, and
load disconnect detections. The device supports both
fully automatic operation and software programmability.
The device also supports new 2-event classification and
Class 5 for detection and classification of high-power
PDs. The device supports single-supply operation, pro-
vides up to 70W to each port (Class 5 enabled), and still
provides high-capacitance detection for legacy PDs.
The device features an I
interface, and is fully software configurable and pro-
grammable. The device provides instantaneous readout
of port current and voltage through the I
The device provides input undervoltage lockout (UVLO),
input overvoltage lockout (OVLO), overtemperature pro-
tection, and output voltage slew-rate limit during startup.
The device is reset by any of the following conditions:
1) Power-up/down. Reset condition is asserted once
2) Hardware reset. To initiate a hardware reset, pull
3) Software reset. To initiate a software reset, write a
4) Thermal shutdown. The device enters thermal shut-
During normal operation, changes to the address inputs,
MIDSPAN, EN_CL5, and AUTO are ignored, and they
can be changed at any time prior to a reset state. At the
end of a reset event, the device latches in the state of
these inputs.
Set RESET_P_ (R1Ah[3:0]) high anytime during normal
powered operation to turn off port_, disable detection
and classification, and clear the Port_ Event and Status
registers. If a port is not powered, setting RESET_P_ high
for that port has no effect. Individual port reset does not
initiate a global device reset.
V
EN low to DGND for at least 100Fs. Hardware reset
clears once, EN returns high to V
are set to their default states.
logical 1 to the RESET_IC register (R1Ah[4]) any time
after power-up. Reset clears automatically, and all
registers are set to their default states.
down at +140NC. The device exits thermal shutdown
and is reset once the temperature drops below
120NC.
EE
falls below the UVLO threshold.
Detailed Description
Quad, IEEE 802.3at/af PSE Controller
2
C-compatible, 3-wire serial
DD
, and all registers
Port Reset
2
C interface.
Reset
for Power-over-Ethernet
In midspan mode, the device adopts cadence timing
during the detection phase. When cadence timing is
enabled and a failed detection occurs, the ports wait
at least 2s before attempting to detect again. Midspan
mode is activated by setting MIDSPAN high and then
powering or resetting the device. Alternatively, midspan
mode can be software programmed individually for
each port by setting MIDSPAN_ (R15h[3:0], Table 23) to
a logical 1. By default, the MIDSPAN input is internally
pulled high, enabling cadence timing. Force MIDSPAN
low to disable this function.
The device provides four operating modes to suit differ-
ent system requirements. By default, auto mode allows
the device to operate automatically at its default settings
without any software. Semiautomatic mode automatically
detects and classifies devices connected to the ports,
but does not power a port until instructed to by software.
Manual mode allows total software control of the device
and is useful for system diagnostics. Shutdown mode
terminates all activities and securely turns off power to
the ports.
Switching between auto, semiautomatic, and manual
mode does not interfere with the operation of an out-
put port. When a port is set into shutdown mode, all
port operations are immediately stopped and the port
remains idle until shutdown mode is exited.
By default, when the auto input is unconnected, the
device enters auto mode after power-up or when the
reset condition is cleared. To manually place a port into
auto mode from any other mode, set the corresponding
port mode bits (R12h[7:0]) to [11] (Table 19).
In auto mode, the device performs detection, classifica-
tion, and powers up the port automatically if a valid PD
is connected to the port. If a valid PD is not connected
at the port, the device repeats the detection routine con-
tinuously until a valid PD is connected.
When entering auto mode after a reset condi-
tion (state of AUTO input), the DET_EN_ and
CLASS_EN_ bits (R14h[7:0], Table 22) are set to high
and stay high, unless changed by software. When enter-
ing auto mode from any other mode due to a software
command (programmed with R12h[7:0], Table 19, the
DET_EN_ and CLASS_EN_ bits retain their previous state.
Auto (Automatic) Mode
Operation Modes
Midspan Mode
15