Austin, Tex.Silicon Laboratories Inc. has introduced the Si345x family of Power over Ethernet (PoE) Power Sourcing Equipment (PSE) controllers that are capable of supporting four independent PoE (IEEE 802.3af) and PoE+ (IEEE 802.3at) PSE ports.
The Si345x controllers offer real-time power measurement capabilities, energy-efficient powered device (PD) detection and disconnect algorithms, and low on-resistance power field-effect transistors (FETs) and sense resistors. These features enable smaller, highly energy-efficient and lower-cost PoE/PoE+ Ethernet switches and midspans designed to power multi-radio wireless access points, industrial automation systems, VoIP phones, and building security and surveillance systems.
The Si345x controllers incorporate high-precision current and voltage monitoring capability to measure the power consumed by each port in real-time, enabling systems to maintain tighter control of power allocation. This approach enables smaller power supplies and lower supply overhead and gives system administrators visibility into how much power is allocated to and consumed by each port in their network.
By employing a method called dV/dt disconnect, an Si345x controller is able to detect the absence of a connected powered device through proprietary measurement techniques, avoiding the use of dc disconnect or power-hungry series diodes and extra BOM components associated with ac disconnect. The dV/dt disconnect feature helps eliminate expensive thermal management components, such as heat sinks and fans.
For example, compared to a PoE+ PSE system implemented with an ac disconnect-based PSE controller, a product using the Si345x's dV/dt disconnect algorithm, integrated low on-resistance FETs and current sense resistors saves nearly 500 mW per port in power consumption or approximately 24 W in a 48-port system, according to the company.
Each Si3452 supports four PoE or PoE+ PSE ports, with proprietary support for power levels up to 40 W per port. A 0.3 ohm power MOSFET, current sense resistor and a proprietary transient voltage surge suppressor are integrated on each port, simplifying the bill of materials to a single capacitor, reducing per port costs by up to $0.20 and saving up to 55 percent in PCB space, according to the company.
The Si345x family is supported by a complete set of development tools, including a Power Manager Software Development Kit and 8-port midspan evaluation system (Si3452MS8-KIT).
Fully compliant with the IEEE 802.3at standard, the environmentally friendly Si3452/3 controllers are available in RoHS-compliant, 6 x 6 mm QFN packaging.
Pricing: $3.40 in 10K quantities; the Si3452MS8-KIT costs $345.
Availability: Samples and production quantities are available now. Industrial temperature range devices are also available now.
Datasheets: click here
Silicon Laboratories Inc., www.silabs.com