SI3453C-B01-GM Silicon Laboratories Inc, SI3453C-B01-GM Datasheet - Page 19

• Manufacturer Part Number: SI3453C-B01-GM
• Description: IC POE CONTROLLER MIDSPAN 40QFN
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3453C-B01-GM

• Package / Case: 40-QFN
• Controller Type: Power over Ethernet Controller (POE)
• Interface: I²C
• Voltage - Supply: 3 V ~ 3.6 V
• Current - Supply: 14mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Maximum Power Dissipation: 1.2 W
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Product: Ethernet Controllers
• Standard Supported: IEEE 802.3at, IEEE 802.3af
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 3 V
• Supply Current (max): 14 mA
• Maximum Operating Temperature: + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 336-1840-5

Once a port is turned on, I
during port turn on because inrush can trigger the I
on with the automatic I
PD and PSE have negotiated for a different I
The Si3452/3 supports 2-Event classification as defined in the IEEE 802.3at draft. 2-event classification is an
alternative to L2 power management where the PSE advertises it is capable of PoE powering by generating two
classification pulses. 2-Event classification is only supported for auto mode. If the Si3452/3 is in auto mode and the
first event classification result is class 4, the mark, second event and second mark are performed. Power is applied
only if the second event is also class 4. If the second event is not class 4, the classification error is reported and the
port will not power.
If the port is in manual mode, classification is done prior to turning on the port. It is not possible to turn on a port
that gives classification overload or gives unequal results for 2-Event classification.
5.5. Command and Return Registers (Registers 0x12–0x1C)
The global command register enables manual port turn on or turn off, chip reset, port reset and measurement of
port current and V
If the command results in a numerical return value, that value is stored in the measurement registers which are
read only. Each of the five possible measurements results in a 2 byte return value and that value is stored in a
unique register. V
full scale is 6.5535 A.
The data for the return value is only updated after a command. This means, that the numerical value of the port
current or V
port turns off due to an overload or disconnect the port current register contents will not be set to zero. If a
command to read port current is issued and the port is off, the return value will be zero.
5.6. Device Status Register (0x1D)
The device event bits are listed in Table 17.
The Device status register is RO. The V
or temperature is out of range and reset if the V
there is a change in the overtemp status (bit 6 of 0x1D), and bit 5 of the Interrupt register is set if there is a change
in the V
not clear the device status register.
In addition, bit B0 indicates whether or not detection back off is used. For PSEs that are wired as Alternative B
(power on the spare pair, typically used for midspans), the time between detection pulses is increased to slightly
over two seconds to avoid interference with Alternative A (power on the data pair, typically used for endpoints). Bit
B0 can be toggled using the command code 0x10.
B6 - OverTemp
B5 - V
EE
UVLO status (bit 5 of 0x1D). Reading register 0x1D clears these bits of the Interrupt register but does
Bit
EE
EE
UVLO
voltage in the measurement register will be the value at the time the command was issued. If the
EE
EE
. It is a Write only register. See Table 23 on page 23 for a list of all available commands.
is encoded in mV units so the full scale is 65.535 V and Iport is encoded in 100 µA units so the
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The Si3452/3 has per port thermal shutdown sensors as well a global thermal shutdown
at a slightly higher temperature. The global thermal shutdown bit of the device event
register is set if this occurs.
V
setting and then later change this value after port current has stabilized and also if the
EE
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UVLO. The part is put in it’s reset state if V
can be changed dynamically. It is often un-desirable to use a low value of I
EE
Table 17. Device Status Bits
, UVLO, and overtemp bits reflect the device status. They are set if V
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EE
value based on the PoE L2 power negotiation protocol (LLDP).
or temperature is in range. Bit 6 of the Interrupt register is set if
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Rev. 0.42
event. For this reason, it is normal to allow the port to turn
Description
EE
is not in a valid range.
Si3452/3
CUT
EE
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