DC1249A

DC1249A demonstration circuit is a PoE to 3.3V at 3.0A Isolated Converter featuring the LTC4267CDHC-3. The board provides a complete IEEE 802.3af power device (PD) interface and isolated 3.3V power supply solution for use in Power-over Ethernet (PoE) applications in a very small printed circuit board footprint. The LTC4267-3 integrates the 25kΩ signature resistor, classification current source, thermal overload protection, signature disable and power good signal along with an undervoltage lockout optimized for use with the IEEE required diode bridge. The precision dual level input current limit allows the LTC4267-3 to charge load capacitors and interface with legacy PoE systems. The LTC4267-3 combines the above features with a current mode switching controller designed for driving a N-channel MOSFET. It features programmable slope compensation, soft-start, and constant frequency operation, minimizing electrical noise even with light loads.

• Power converter input operating range from -37V to -57V (VOUT = 3.3V, IOUT = 0 to 3.0A)
• 375mA (typical) maximum input current
• 3.0A maximum output current (VOUT = 3.3V )
• 3.3V typical output voltage