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PoE PSE controllers deliver 90W of power

Posted: 01 Jul 2011 ?? ?Print Version ?Bookmark and Share

Keywords:power controller? power management? power device discovery?

Linear Technology Corp. has debuted the LTC4266A and LTC4274A, 4-port and single-port Power over Ethernet (PoE) controllers that offers up to 90W of power to powered devices (PDs). The devices address the higher power PoE market using Linear's LTPoE++ signaling scheme, while ensuring backward compatibility and interoperability with equipment based on the existing IEEE PoE standard. Linear offers high power versions, 35W, 45W, 70W and 90W, so that discrete components and magnets can be sized accordingly, minimizing total solution costs. Low power 13W versionsLTC4266C and LTC4274Care also available for fully automatic Type 1 PoE systems.

The LTC4266A and LTC4274A enable a new generation of high power PoE applications, including long range wireless access points (WAP), thin clients and heated surveillance cameras, Linear said.

Key benefits of the devices include extremely low power dissipation across low RDS (ON) MOSFETs and sense resistors (0.34? total per port). Linear Technology LTPoE++ PDs can request up to 90W of power by responding to a proprietary classification mechanism, confirming that the PD is indeed a high power LTPoE++ compliant device. Very high reliability PD discovery is accomplished using a proprietary dual-mode, four-point detection mechanism that ensures the best immunity from false PD detection. Linear added that the PSE controllers offer advanced power management that includes prioritized fast shutdown, accurate 14.5bit per-port voltage and current read back, 8bit programmable current limits and 7bit programmable overload current limits. A 1MHz I2C interface allows a host controller to digitally configure the IC or to query port readings while the firmware is conveniently field upgradable.

The LTC4266A/C and LTC4274A/C offer guaranteed specifications for operation in industrial environments, and are available in a RoHS-compliant 5x7mm QFN-38 package. They are priced at $5 and $4.50 each, respectively, in 1,000 piece quantities and are available in production quantities. Application circuits for both LTPoE++ PSE and PD controllers are also available.

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