MAXIM, represented by Arrow Electronics , has introduced the MAX5922, the industry's first fully integrated IEEE802.3af-compliant 48V power switch for Power-over-Ethernet (LAN) systems.
This highly integrated and robust solution simplifies design while reducing external component count and board space.
The MAX5922 is used in IEEE802.3af-compliant network switches and routers, or midspan power-insertion units that deliver power to network ports.
This device allows IP phones, wireless LAN access nodes, and IP security cameras to be remotely powered over the network without causing glitches on the system power-supply rail.
Rated for 32V to 60V operation, the MAX5922 is fully compliant with the IEEE802.3af standard.
Before applying power to a device (load), the MAX5922 detects the presence of a valid 25kΩ discovery signature and one of the valid classification characteristics specified in the IEEE802.3af standard.
An internal 0.45Ω power MOSFET limits the inrush current drawn by the power device during startup. After startup, the device provides short-circuit protection.
Other features include input undervoltage lockout (UVLO), thermal shutdown, and zero-current load disconnect.
Error flag outputs monitor four fault conditions: UVLO, power-not-good, zero-current detection, and thermal shutdown. If any fault condition occurs, the error flag outputs are asserted low to alert the system microprocessor.
The MAX5922 is available in a surface-mount, 20-pin TSSOP package specified for the extended temperature range (-40°C to +85°C).