MAX5980GTJ+T Maxim Integrated, MAX5980GTJ+T Datasheet - Page 17

• 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

Table 2. PSE Classification of a PD (Table 33-9 of the IEEE 802.3at Standard)
To prevent damage to non-PD devices, and to protect
itself from an output short circuit, the device limits the
current into OUT_ to less than 2mA (max) during PD
detection. In midspan mode, after every failed detection
cycle, the device waits at least 2.0s before attempting
another detection cycle.
High-capacitance detection for legacy PDs is soft-
ware programmable. To use the software to enable
high-capacitance detection, set LEG_EN_ (Port GPMD
registers, Table 39) to 1 during normal operation. If high-
capacitance detection is enabled, PD signature capaci-
tances up to 100FF (typ) are accepted.
During PD classification, the device forces a probe volt-
age between 15V and 20V at OUT_ and measures the
current into OUT_. The measured current determines the
class of the PD.
After each classification cycle, the device sets
CLS_ (R04h[7:4] and R05h[7:4], Table 9) to 1 and reports
the classification results in the classification status bits
(see Table 13). The CLS_ bits are reset to 0 when read
through the CoR (clear on read) register (R05h) or after
a reset event.
MEASURED I
Power Device Classification
> 13 and < 16
> 21 and < 25
> 31 and < 35
> 45 and < 51
> 5 and < 8
16 to 21
25 to 31
35 to 45
Quad, IEEE 802.3at/af PSE Controller
8 to 13
High-Capacitance Detection
0 to 5
CLASS
(PD Classification)
(mA)
for Power-over-Ethernet
If EN_CL5 is left unconnected, the device will classify the
PD based on Table 33-9 of the IEEE 802.3at standard
(see Table 2). If the measured current exceeds 51mA,
the device will not power the PD, but will report an over-
current classification result and will return to IDLE state
before attempting a new detection cycle.
The device supports high power beyond the IEEE
802.3at standard by providing an additional classifica-
tion (Class 5) if needed. To enable Class 5, connect
EN_CL5 to V
ware to individually enable Class 5 classification for each
port (R1Ch[3:0], Table 29). Once Class 5 is enabled,
during classification, if the device detects currents in
excess of the Class 4 upper-limit threshold, the PD will
be classified as a Class 5 powered device. The PD is
guaranteed to be classified as a Class 5 device for any
classification current from 51mA up to the classification
current-limit threshold. The Class 5 overcurrent threshold
and current limit will be set automatically with ICUT_[5:0]
and ILIM_ (see Tables 40 and 41). Leave EN_CL5
unconnected to disable Class 5 detection and to be fully
compliant to IEEE 802.3at standard classification.
DD
and initiate a global reset or use the soft-
Either Class 4 or Invalid
May be Class 0 or 1
CLASSIFICATION
Either Class 1 or 2
Either Class 2 or 3
Either Class 3 or 4
Class 0
Class 1
Class 2
Class 3
Class 4
Class 5 PD Classification
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