Sunnyvale, Calif. - Maxim Integrated Products bills its
MAX5941/MAX5942 as the industry's first fully integrated power-over-Ethernet (PoE) DC/DC controller. The chip, which includes a current-mode PWM section and interface for powered devices (PDs), is suited to both forward and flyback converters in both isolated (MAX5941) and nonisolated (MAX5942) designs.
Fully compliant to the IEEE802.3af standard, the chip is rated for up to +67-volt operation and more than 15 watts output. Interface circuitry detects the powered device's 25 kilohms signature, classification signature, and provides programmable control of inrush current. The chip also features programmable undervoltage lockout.
The PWM controller features wide input range (18-67 volts), soft-start, leading-edge blanking, and an oscillator internally trimmed to a switching frequency of 275 kHz±10 percent to reduce magnetics and filter components. Other features include over-current shutdown, and thermal shutdown.
The MAX5941/MAX5942 is rated for operation over the commercial (0 to +70°C) and extended (-40 to
+85°C) temperature ranges in a surface-mount, 16-pin
SO package. Prices start at $1.47 each for the MAX5941 and $1.55 for the MAX5942 (1k-and-up quantities).