DC1049A

DC1049A demonstration circuit is a high-power triple output supply featuring the LTC4264 with the LTC3825. 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 LTC4264 provides IEEE802.3af standard PoE PD interfacing. When the PD is fully powered, the LTC4264 switches power over to the LTC3825 through an on-board high-power MOSFET. The highly integrated LTC3825, small supply utilizes an isolated flyback topology with synchronous rectification that requires no opto-isolator allowing for low parts count. The DC1049 output supplies are 5V at 2A, 11.8V at 0.27A, and 3.3V at 2.5A. DC1049 also demonstrates the use of an auxiliary 24V wall adapter. When present, the auxiliary supply becomes the dominant supply over PoE to provide power to the LT3825.

• PoE input voltage range from 37V to 57V
• 750mA PoE input high current limit at ILIM-EN enabled, nominal current
• 1.45A PoE input high current limit at ILIM-EN disabled, nominal current
• 23.25kohm to 26.00kohm PoE signature resistance at SHDN enabled
• 24V auxiliary input voltage: 22.8V to 57V at in from auxiliary supply
• 250kHz nominal switching frequency
• 1500V DC isolation voltage