SI3461-KIT Silicon Laboratories Inc, SI3461-KIT Datasheet - Page 5

• 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

5.1. PSE Detection, Classification, Power-Up, and Power Removal
The basic sequence for applying power is shown in Figure 5. The following is a description of the functions that
must be performed in each phase.
5.1.1. Detection
During the detection phase, the PSE probes with limited current and voltage to determine if a 25 k signature is
present. A valid PD must present between 23.75 and 26.25 k in the range of 2.8 to 10 V with an offset (due to the
bridge diodes) of up to 1.9 V and a parallel capacitance of between 0.05 and 0.12 µF.
The Si3461-EVB uses a robust 3-point detection sequence to avoid inadvertently powering and damaging a
non-PoE-enabled device.
For endpoint applications, detection must be completed within 500 ms of applying a valid signature. When
configured as a midspan, there is a possibility that the PSE circuit will compete with an endpoint PSE, and, as
required by the IEEE specifications, the Si3461 waits at least two seconds after an unsuccessful detection cycle to
repeat the detection process.
20.5 V
15.5 V
2.8 V
57 V
10 V
44 V
Figure 5. Detection, Classification, Power-Up, and Disconnect Sequence
t
DET_CYCLE
t
CLASS_CYCLE
Rev. 0.5
t
PWRUP
Si3461-EVB
(msec)
Time
5