DC1080A

DC1080A demonstration circuit features the LTC®4268-1 high-power triple output high efficiency POE power device. This board acts as a pre-standard high-power Power-over Ethernet (PoE) Powered Device (PD) and connects at the RJ45 to a compatible high-power Power Sourcing Equipment (PSE) device. The LTC4268-1 provides IEEE802.3af standard PoE PD interfacing. When the PD is fully powered, the PD interface switches power over to the switcher through an on-board high-power MOSFET. The highly integrated LTC4268-1, small supply utilizes an isolated flyback topology with synchronous rectification that requires no opto-isolator allowing for low-parts count. The DC1080A output supplies are 5V at 2.4A, 11.8V at 0.27A, and 3.3V at 2.5A. DC1080A also demonstrates the use of an auxiliary 24V wall adapter. When present, the auxiliary supply becomes the dominant supply over PoE to provide power.

• PoE input voltage range from 37V to 57V
• 750mA PoE input high current limit at ILIM-EN enabled, nominal current, TA = 25°C
• PoE signature resistance: 23.25kohm to 26.00kohm at SHDN enabled
• 24V auxiliary input voltage: 22.8V to 57V (in from auxiliary supply)
• 250kHz nominal switching frequency
• 1500V DC isolation voltage