SI3461-KIT Silicon Laboratories Inc, SI3461-KIT Datasheet - Page 9

• Manufacturer Part Number: SI3461-KIT
• Description: BOARD EVAL FOR SI3461
• Manufacturer: Silicon Laboratories Inc
• Type: Controllers & Processorsr

Specifications of SI3461-KIT

• Main Purpose: Special Purpose DC/DC, Power Over Ethernet
• Board Type: Fully Populated
• Utilized Ic / Part: Si3461
• Ethernet Connection Type: 10/100 Base-T, IEEE 802.3
• Interface Type: Ethernet
• Operating Voltage: 12 V to 15 V
• Operating Current: 10 mA
• Product: Modules
• For Use With/related Products: Si3460
• Lead Free Status / RoHS Status: Lead free / RoHS non-compliant
• Current - Output: -
• Voltage - Output: -
• Voltage - Input: -
• Power - Output: -
• Frequency - Switching: -
• Outputs And Type: -
• Regulator Topology: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1843

one-event result. If the first event ended with a Class 4 result, then the second event is generated, and a valid
Class 4 PD is only recognized if Class 4 is detected during the second event as well.
For less than 30 W of available power, only the one-event method is used. In this case, if a Class 4 PD is detected,
only 15.4 W of power is granted.
If the class level of the PD is not within the supported level as set by the initial voltage on the Si3461's STATUS pin
(refer to the Operating Mode Configuration section above), an error is declared, and the LED blinks rapidly at a rate
of 10 Hz for two seconds before the Si3461 goes back to the detection cycle. This is referred to as
classification-based power denial. If the class level is in the supported range, the Si3461 proceeds to powerup.
This is referred to as classification-based power granting. Classification level is determined according to the
current measured at the ISENSE input as shown in Table 3.
6.4. Power-Up
After successful classification, the pass FET is turned on with a current limit corresponding to the classification
results as indicated in Table 3. After powerup, power is applied to V
disconnect, or input under-voltage (UVLO) or over-voltage condition. The STATUS LED is continuously lit when
power is applied.
If the output power exceeds the level of the power requested during classification, the Si3461 will declare an error
and shut down the port, flashing the LED rapidly to indicate the error (for either two seconds or until an open-circuit
condition is detected as determined by the initial voltage on the STATUS pin).
The Si3461-EVB implements two levels of overload protection:


If the Si3461 was configured to operate in the automatic retry mode, it will retry detection and power up after an
overload. In this case, the status LED will flash rapidly for two seconds to show the error condition, and then the
Si3461 will automatically initiate a new detection cycle while the status LED flashes at a rate of 1.5 Hz.
Alternatively, the Si3461 can be programmed to signal that an error condition has occurred, in which case the user
must disconnect the Ethernet cable and plug it in again (or push the reset switch on the Si3461-EVB) to start a new
detection and powerup cycle. In this case, the status LED flashes rapidly until an open-circuit is detected and then
flashes at a rate of 1.5 Hz to show that a new detection cycle is in progress. Power is provided again only after
successful detection and classification. The Si3461-EVB does not regulate the output voltage during the power-on
state. Input voltage changes will be transmitted to the output directly.
ISENSE Current
(Nominal)
< 6.5 mA
6.5 mA to 14.5 mA
14.5 mA to 23 mA
23 mA to 33 mA
33 mA to 48 mA
*Note: The I
The output current is limited to the ILIM value corresponding to the classification level detected (refer to
Table 3). During the powerup transient, phase output current is limited to 425 mA, independent of the
classification level.
If the output current exceeds I
values). Additionally, for Class 4 devices, if current limitation persists longer than 15 ms, power will also be shut
down to protect the pass FET.
effective output voltage.
CUT
overload thresholds are dynamically calculated as a function of the granted power and the
Classification
Class 0
Class 1
Class 2
Class 3
Class 4
Level
CUT
for longer than 60 ms, the output is shut down (refer to Table 3 for the I
Table 3. Classification Levels
Type
PSE
1
1
1
1
2
Power Level
Minimum
Rev. 0.5
15.4 W
15.4 W
26.4 W
4 W
7 W
Threshold I
OUT
Overload Current
16,500/Vout
16,500/Vout
33,200/Vout
as long as there is no overcurrent fault,
4,300/Vout
7,500/Vout
[mA]*
CUT
(Typ)
Si3461-EVB
Overload Current
Limit I
[mA]
425
425
425
425
885
LIM
(Typ)
CUT
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