Isolated four-port PoE PSE controller conforms to IEEE 802.3bt 

Believed to be the first of its kind to pass a series of IEEE 802.3bt (PoE++) power over Ethernet (PoE) conformance test, the LTC4291 and LTC2492 are available from Analog Devices.

The Power by Linear isolated four-port power source equipment (PSE) controller chipset passes conformance tests administered by Sifos Technologies.

PoE presents PSE evaluation challenges in somuchas PSEs are multi-channel, intelligent DC power sources that are activated and deactivated through standardised processes without disrupting traditional Ethernet data transmission. At the same time, compliance testing is complicated by requirements to operate over several delivery and polarity configurations, reports Analog Devices (ADI).

The Sifos 24-port PSA-3000 PowerSync analyser equipped with multiple two-port PSA-3202 test blades provides complete automated testing and analysis of LTC4291/92-based PSEs. Rigorous compliance test suites augmented by specialised analysis features validated the LTC4291/92 to the IEEE 802.3at (PoE+) standard, the upcoming 802.3bt standard, and other proprietary specifications.

These devices can reduce time-to-market and enable deployment of IEEE 802.3bt PoE networks which is due to be ratified this year.

In testing performed by Analog Devices, the LTC4291/92 PSE chipset passed a variety of tests as the PSA-3000/3202 emulated a variety of IEEE 802.3bt powered devices (PDs). Continuous 90W four-pair PSE loading capability ensures that the PSE could handle 802.3bt’s 71.3W maximum PD power level in either single- signature or dual-signature PD configurations.  The LTC4291/92 correctly identified all physical layer classes (up to five events) as required by the new Type 3 and Type 4 PDs, as well as the backward compatible Type 1 and Type 2 PDs. For PSEs that use the link layer discovery protocol (LLDP), the PSA-3000/3202 can also emulate and analyse this type of power negotiation.

Customers configure and interact with the devices using provided graphical user interfaces (GUIs) and scripting environments. The LTC4291/92 is supported with lab-tested schematics, complete reference designs, the QuikEval GUI and example code, while the PSA-3000/3202 is extended with the PSA interactive GUI and PowerShell PSA scripting environment.

The LTC4291/92 chipset is offered in commercial and industrial temperature ranges.  The LTC4291 digital controller is offered in a RoHS-compliant 24-pin 4.0 x 4.0mm QFN package. The LTC4292 analogue controller is in a 40-pin 6.0 x 6.0mm QFN package. The LTC4291/92 is Analog Devices’ first 802.3bt PSE controller and provides an upgrade path for its LTC4266 4-port 802.3at PSE controller.

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