DEMO MANUAL DC1567B LTC4274 Single Port IEEE802.3at PSE DESCRIPTION Demonstration circuit 1567B features the LTC 4274, a The LTC4274 delivers low heat dissipation by utilizing a single power sourcing equipment (PSE) controller designed low R external MOSFET and a 0.25 sense resistor, ON for use in IEEE 802.3 Type 1 and Type 2 (high power) com- eliminating the need for expensive heat sinks. An external pliant Power over Ethernet (PoE) systems. The LTC4274 MOSFET also provide a more robust solution compared is configured in the DC1567B as a midspan power injector to an integrated MOSFET. where data comes in from an existing network system Power controlled by the LTC4274 is connected to the center and out, along with power, to a powered device (PD). The taps on the cable side of the Ethernet transformers for data LTC4274 autonomously detects and classifies a PD, turns pairs 4/5 and 7/8. An integrated RJ45 connector includes power on to the port, and disconnects port power without the Ethernet transformer, common mode termination, the need for a microcontroller. A two second backoff timer and LEDs. One LED is also controlled by the LTC4274 supports the midspan configuration. to indicate the port is powered. Test turrets provide test Only a single 55V supply is required to power the DC1567B. points for port power measurements. A simple regulator circuit on the board powers the digital The DC1567B has increased surge protection from the supply of the LTC4274. DC1567A. The DC1567B is Ethernet Alliance certified. Design files for this circuit board are available. All registered trademarks and trademarks are the property of their respective owners. www.analog.com Rev B 1DEMO MANUAL DC1567B TYPICAL PERFORMANCE Table 1. Typical DC1567B Performance Summary (T = 25C) A PARAMETER CONDITION VALUE Input Voltage GND V , Typical Voltage, IEEE Type 1 and Type 2 Complaint 51V to 57V EE Output V Supply Voltage V DGND, Generated on Demo Board from V 3.4V to 3.8V DD DD EE Powered Pairs PoE Power at RJ45 Connector Alternative-B (Positive on Pins 4/5, Negative on 7/8) PSE Operation Mode AUTO Pin Logic High IEEE802.3at Mode Midspan Backoff MID Pin Logic High, Backoff Time After Detection 2.5s Detection Type 25k Signature Detection 4-Point PD Detection Class 4 2-Event Classification RJ45 Amber LED Indicator PD Detected and Port Power is On LED On Port Power is Off LED Off Port Output Voltage V = 55.0V, R = 0.25, MOSFET = PHT6NQ10T, 54.7V EE SENSE + Port Load = 600mA, VPORT VPORT Disconnect Current DC Disconnect, Maintain Power Signature, Typical Disconnect <7.8mA Current at the Port for 350ms, R = 0.25 SENSE AUTO Pin High Mode R = 0.25, Class 0 or Class 3 376mA SENSE Overcurrent Sense R = 0.25, Class 1 112mA SENSE R = 0.25, Class 2 208mA SENSE R = 0.25, Class 4 636mA SENSE Rev B 2