DC1814A-D Analog Devices

DEMO MANUAL DC1814A LTC4274A ++ Single LTPoE PSE Controller Description Demonstration circuit 1814A features the LTC 4274A, The LTC4274A is configured in the DC1814A as an AUTO single port power sourcing equipment (PSE) controller, pin high, MID pin high, autonomous midspan power injec- ++ capable of delivering up to 90W of LTPoE power to a tor input data from an existing network system is sent out, ++ compatible LTPoE powered device (PD). A proprietary along with power, to a PD. The LTC4274A autonomously detection/classification scheme allows mutual identifica- detects a PD, turns power on to the port, and disconnects ++ ++ tion between an LTPoE PSE and LTPoE PD while port power without the need for a microcontroller. A single remaining compatible and interoperable with existing 55V supply is required to power the DC1814A. A simple Type 1 (13W) and Type2 (25.5W) PDs. The LTC4274A LDO regulator circuit on the board powers the digital sup- feature set is a superset of the popular LTC4274. These ply of the LTC4274A. A SHDN pushbutton shuts down the PSE controllers utilize low R external MOSFETs and port and disables detection. A RESET pushbutton resets ON 0.25 sense resistors which are especially important at the LTC4274A to the AUTO pin high state. ++ the LTPoE current levels to maintain the lowest possible Design files for this circuit board are available at heat dissipation. DEMO MANUAL DC1814A Quick s tart p D ++ Demonstration circuit 1814A is easy to set up for evaluat- 2. Connect an 802.3 Type 1 or Type 2, or LTPoE compat- ing the performance of the LTC4274A. Refer to Figure 1 ible PD to RJ45 connector J1 with an Ethernet cable. for proper test equipment setup and follow the procedure 3. Measure the port output voltage to the PD across below. VPORT+ and VPORT test points. 1. Connect a 55V to 57V power supply across AGND (+) 4. (Optional) Connect a PHY to RJ45 connector J2 with and VEE (). Size the power supply considering the an Ethernet cable for data tests. maximum power delivered to the PD. Figure 1. DC1814A Setup dc1814afe 2 ure roce