SI3452D-B01-GM Silicon Laboratories Inc, SI3452D-B01-GM Datasheet - Page 12

• Manufacturer Part Number: SI3452D-B01-GM
• Description: IC POE CONTROLLER MIDSPAN 40QFN
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3452D-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: 336-1835-5

Si3452
4. Functional Description
Integrating four independent, high-voltage PSE port interfaces, the Si3452 high-voltage port controller enables an
extremely flexible solution for virtually any PoE or PoE+ PSE application. The Si3452 provides all of the high-
voltage Power over Ethernet PSE functions.
Each port of the Si3452 integrates all high-voltage PSE controller functions needed for a quad-port PoE design,
including the power MOSFET, efficient current-sensing circuitry, transient voltage surge suppressor, and multiple
detect and disconnect circuits. The external BOM is typically only a single filter capacitor on each high-voltage port.
When a PD device has been properly detected and classified, the port is powered by a –54 V nominal supply with
continuous monitoring of voltage and current for feedback to the host system.
In addition to the required IEEE features, the Si3452 includes many additional features:
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4.1. Detection
The Si3452 has per-port signature detection that satisfies the IEEE Std 802.3™-2005 specifications. However, by
utilizing a 3-point voltage-forced detection method, the Si3452 yields robust recognition of valid and invalid
powered device (PD) signatures, properly identifying signatures often mischaracterized by other detection
techniques.
The detection circuitry performs the function of setting the output voltage on any channel to the proper value for
detection or classification and then measuring the resulting line current.
A typical detection cycle consists of applying 4 V, then 8 V, then 4 V again with the current limit set to 3 mA. The
current is measured after an appropriate settling time. For a valid PD, the detection signature must be compliant
with the detection voltage both increasing and decreasing.
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Figure 4. PSE Sequencing (3-Point Detection Followed by 2-Event Classification and Powerup)
Per port current / voltage monitoring and measurement
Support for 1-Event and 2-Event classification algorithms
Start up in shutdown or auto mode
Alternative A (typically used for endpoint systems) or Alternative B (typically used for midspan systems)
detection timing
Vport Relative to GND
detection
3 point
Rev. 1.2
classification
Port powerup
2 event