SOURCE: Maxim Integrated Products

October 19, 2007 12:16 ET

Maxim Introduces the Industry's First, Quad PSE Controller for High-Power (PoE+) and IEEE 802.3af Applications

SUNNYVALE, CA--(Marketwire - October 19, 2007) - Maxim Integrated Products (PINKSHEETS: MXIM) introduces the MAX5952, a quad Power-Sourcing-Equipment (PSE) controller for high-power (PoE+) and IEEE 802.3af-compliant Power-over-Ethernet (PoE) applications.

Synopsis for Investor:
--  The device enables network switch/routers or midspan power injectors
    to deliver up to 45W of power per RJ-45 port to powered devices (PDs).
    Ideal applications are PDs that require more than the 15W limit set by
    the IEEE 802.3af standard. Examples include IP phones, wireless LAN
    access nodes, and security cameras.
--  Numerous programming and configuration options give unmatched design
    flexibility. Featuring an I2C, 3-wire serial interface, the MAX5952 can
    be controlled with a microcontroller or configured to operate
    autonomously in manual or semi-automatic modes.
--  For more applications flexibility, the MAX5952 is backwards-compatible
    with the IEEE 802.3af standard. It also allows detection of high-
    capacitance, legacy (non-IEEE 802.3af-compliant) powered devices.
--  The MAX5952 is also pin-compatible with the MAX5945 PSE controller and
    the LTC4258/LTC4259A devices for IEEE 802.3af-PSE-compliant systems.
    With minimal extra component changes or added cost, customers can now
    upgrade their existing 802.3af PSE designs for higher power.

The MAX5952 controller allows multiport, high-power PoE+ systems to deliver up to 45W of power over the standard Ethernet cable to power devices (PDs) such as IP phones with color LCD displays, wireless LAN access nodes, and IP cameras.

Overcoming the Power Limits of 802.3af

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 PD device 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.

Meeting the Emerging High-Power PoE+ System Requirements

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

The MAX5952 incorporates Class 4 and Class 5 classification for high-power PDs. An integrated 9-bit analog-to-digital converter (ADC) and with an I2C-compatible, 3-wire serial interface monitors and reports the current drawn by each of the four ports.

Numerous programming and configuration options give the MAX5952 unmatched design flexibility. The device can be controlled with a system microcontroller, 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.

PoE Reference Designs, Samples, and EV Kits Available Now

The MAX5952 has the standard features expected of a PSE controller: input undervoltage lockout detection (UVLO), 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 now. The midspan reference design supports up to 192 ports and includes the MAXQ2000 microcontroller and supporting software. Production samples and evaluation (EV) kits are also available. Contact the factory for more information.

The MAX5952 is packaged in a 36-pin SSOP and rated to operate in the upper commerical temperature range (0 degrees Celsius to +85 degrees Celsius). Pricing starts at $6.33 (1000-up FOB USA). For more information please visit: http://www.maxim-ic.com/PoE-plus

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