SI3452A-B01-IM Silicon Laboratories Inc, SI3452A-B01-IM Datasheet - Page 18

• Manufacturer Part Number: SI3452A-B01-IM
• Description: IC POE CONTROLLER MIDSPAN 40QFN
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3452A-B01-IM

• 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
• Other names: 336-1832-5

Si3452/3
The three detect status bits indicate the last detection result for that port. If a detection has not been done or if the
port is shut down with no new detection result, the detection status is reported as unknown.
5.4. Port Configuration (Registers 0x0A–0x11)
These registers indicate the port configuration; they are read/write registers.
The port priority bit is set if the port is not high priority. Low-priority ports are shut down when the shutdown low-
priority ports command is issued.
The “PoE+“ bit specifies the dc current limit at either 425 mA or 850 mA nominal*.
*Note: The PoE+ mode should be set correctly according to the electrical design of the PSE circuit (transformer and conductor
“Disconnect enable“ must be set for power to be removed if there is a disconnect. The disconnect type (based on
dc disconnect or Silicon Labs’ proprietary dV/dt disconnect) is determined by the ordering part number.
“Port mode“ is set according to Table 17.
I
can be set with 3.2 mA resolution. The accuracy of current measurement is approximately 5%; so, I
set 7% higher than the supported current level. I
PoE+ mode. The automatically-set I
0–3 and for a 51 V minimum power supply for PoE+ mode. This feature is classification policing.
If the Si3452/3 is in the semi-auto mode, I
that if it is desired to set I
Once a port is turned on, I
port turn-on because inrush can trigger the I
the automatic I
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.
18
CUT
Port Mode Setting
is the nominal current level at which the port will automatically power down if I
current carrying capacity). The PoE+ port mode can safely be changed prior to port turn-on, but changes after port turn-
on do not have an immediate effect and are not recommended.
B1, B0
00b
01b
10b
11b
CUT
setting and then later change this value after port current has stabilized and also if the PD and
CUT
CUT
Shutdown
Semiauto
Manual
Mode
Auto
at port turn-on, this should be done before the port is turned on.
can be changed dynamically. It is often undesirable to use a low value of I
CUT
CUT
Table 17. Port Mode Selection
level is appropriate for a 45 V minimum system power supply for classes
value based on the PoE L2 power negotiation protocol (LLDP).
The power is shut down with no detection pulses. A command to manu-
ally power the port is ignored.
The port can be powered by the manual power command.
Detection is done and classification is done for Rgood, but the port does
not power.
Detection classification and port powering are all automatic with no host
intervention required. I
the PoE+ mode and classification result.
CUT
CUT
will not be updated according to the classification result. This means
event. For this reason, it is normal to allow the port to turn on with
CUT
Rev. 0.47
is automatically set based on the classification result and
CUT
and I
Description
LIM
are automatically set according to
CUT
is exceeded for 60 msec. It
CUT
is normally
CUT
during