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Quad PSE controller rolls for high-power PoE apps

Posted: 27 Sep 2007 ?? ?Print Version ?Bookmark and Share

Keywords:quad PSE controller? PoE? Ethernet?


Maxim Integrated Products has released the MAX5952 a quad power-sourcing-equipment (PSE) controller for high-power (PoE+) and IEEE 802.3af-compliant PoE applications. The device allows multiport, high-power PoE+ systems to deliver up to 45W of power over the standard Ethernet cable to power devices such as IP phones with color LCD displays, WLAN access nodes, and IP cameras.

Today's PoE applications require more than 15W of power, the maximum power limit mandated for PSE by the IEEE 802.3af specification. Specifically, the IEEE 802.3af specification mandates that a PSE device can deliver a maximum of 15W of power per RJ-45 port, and that an 802.3af-compliant powered-device (PD) can draw a maximum of 12.95W of power. There are now, however, many power-hungry PDs that require more than the 12.95W 802.3af limit. Customers thus need a PSE controller that supports higher power.

While the MAX5952 meets the 802.3af standard, this new PSE controller is particularly designed for the more demanding, high-power (up to 45W) PoE+ applications. The MAX5952 operates from 32V to 60V, and provides 802.3af PD discovery and classification. It also supports both DC and AC load-disconnect detection methods.

In addition, the controller incorporates Class 4 and Class 5 classification for high-power PDs. An integrated 9bit ADC and with an I2C-compatible, 3-wire serial interface monitors and reports the current drawn by each of the four ports.

Also, numerous programming and configuration options give the MAX5952 unmatched design flexibility. The device can be controlled with a system microcontroller like the MAXQ2000, or configured to operate autonomously in manual or semi-automatic modes. The device can be configured for both endpoint (LAN switches/routers) and midspan (power injectors) PSE applications. The controller's gate-charging current, current-limit threshold, startup timeout, overcurrent timeout, and autorestart duty cycle are all programmable.

To ensure unmatched applications flexibility, the MAX5952 is pin compatible with the MAX5945 PSE controller and other 802.3af PSE controllers on the market. The MAX5952 is thus backwards compatible with 802.3af-compliant systems. With minimal external component modifications or added cost, designers can upgrade existing systems for higher power.

The MAX5952 also has the standard features expected of a PSE controller including input undervoltage lockout detection, load-stability safety check during detection, overtemperature protection, output voltage slew-rate limit during startup, power-good and fault status.

Reference designs for both endpoint PSE and midspan PSE applications are available. The midspan reference design supports up to 192 ports and includes the MAXQ2000 MCU and supporting software. Production samples and evaluation kits are also available.

The MAX5952 is packaged in a 36-pin SSOP and rated to operate in the upper commercial temperature range (0C to 85C). Pricing starts at $6.33 (1000-up FOB USA).

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