DEMO MANUAL DC1567B LTC4274 Single Port IEEE802.3at PSE Description Demonstration circuit 1567B features the LTC®4274, a single power sourcing equipment (PSE) controller designed for use in IEEE 802.3 Type 1 and Type 2 (high power) compliant Power over Ethernet (PoE) systems. The LTC4274 is configured in the DC1567B as a midspan power injector where data comes in from an existing network system and out, along with power, to a powered device (PD). The LTC4274 autonomously detects and classifies a PD, turns power on to the port, and disconnects port power without the need for a microcontroller. A two second backoff timer supports the midspan configuration. Only a single 55V supply is required to power the DC1567B. A simple regulator circuit on the board powers the digital supply of the LTC4274. The LTC4274 delivers low heat dissipation by utilizing a low RON external MOSFET and a 0.25Ω sense resistor, eliminating the need for expensive heat sinks. An external MOSFET also provide a more robust solution compared to an integrated MOSFET. Power controlled by the LTC4274 is connected to the center taps on the cable side of the Ethernet transformers for data pairs 4/5 and 7/8. An integrated RJ45 connector includes the Ethernet transformer, common mode termination, and LEDs. One LED is also controlled by the LTC4274 to indicate the port is powered. Test turrets provide test points for port power measurements. The DC1567B has increased surge protection from the DC1567A. Design files for this circuit board are available at http://www.linear.com/demo/DC1567B L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. dc1567bfa 1 DEMO MANUAL DC1567B Typical Performance Table 1. Typical DC1567B Performance Summary (TA = 25°C) PARAMETER CONDITION VALUE Input Voltage GND – VEE, Typical Voltage, IEEE Type 1 and Type 2 Complaint Output 51V to 57V VDD Supply Voltage VDD – DGND, Generated on Demo Board from VEE 3.4V to 3.8V 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 PD Detected and Port Power is On LED On Port Power is Off LED Off Port Output Voltage VEE = –55.0V, RSENSE = 0.25Ω, MOSFET = PHT6NQ10T, Port Load = 600mA, VPORT+ – VPORT– –54.7V Disconnect Current DC Disconnect, Maintain Power Signature, Typical Disconnect Current at the Port for 350ms, RSENSE = 0.25Ω <7.8mA AUTO Pin High Mode Overcurrent Sense RSENSE = 0.25Ω, Class 0 or Class 3 376mA RSENSE = 0.25Ω, Class 1 112mA RSENSE = 0.25Ω, Class 2 208mA RSENSE = 0.25Ω, Class 4 636mA RJ45 Amber LED Indicator 2 dc1567bfa DEMO MANUAL DC1567B Quick Start Procedure (Figure 1) 1.Connect a 55V power supply across AGND and VEE as shown in Figure 1. 2.Connect probes across VPORT+ and VPORT– for measurements. 3.Connect with a CAT5 cable to a PD at J1. 4.Connect a PHY with a CAT5 cable to J2 for data testing (optional). 55V +– Data in from PHY VPORT V RJ45 RJ45 Data and Power Out to PD DC1567B F01 Figure 1. DC1567B Setup dc1567bfa 3 DEMO MANUAL DC1567B Operation DC1567B provides a simple single port IEEE 802.3at Type 1 and Type 2 PSE solution with the LTC4274. It runs fully autonomously and only requires a supply at VEE. Detection, classification, port power on and disconnect is all performed without the need of a microcontroller. The voltage drop to the port is minimized with the LTC4274 solution because of the low RON external MOSFET and a 0.25Ω sense resistor, thus reducing power consumption. Input Supply IEEE 802.3at requires that a Type 2 PSE output at the port between 50V to 57V. To meet this requirement, it is recommended to supply a nominal 55V across AGND and VEE on the DC1567B as shown in Figure 1. Main PS LED indicates the input power supply is powering the LTC4274. VDD Supply DC1567B generates a VDD supply from VEE using just three components allowing for VEE to be the only required supply. VDD is tied to AGND and DGND is a negative voltage below AGND. AUTO Pin High Mode The AUTO pin on the LTC4274 is tied logic high on the DC1567B to set the device to AUTO pin high mode. In AUTO pin high mode, the LTC4274 autonomously detects, classifies, powers on a valid detected PD, and disconnects power to the port when the PD is removed. An LED in the integrated RJ45 connector displays if the port is powered. Midspan The LTC4274 on the DC1567B, the MID pin is tied logic high to set the device to midspan mode. In midspan mode, port detection occurs every midspan backoff time of 2.5s. 4 Detection and Classification The LTC4274 performs 4-point PD detection with 2-point forced voltage and 2-point forced current for higher reliability of valid PD detection. Once a valid PD is detected, classification is carried out. The LTC4274 in AUTO pin high mode detects and classifies class 0 through class 4 PDs and sets the port current limits according to the PD class. In the event a class 4 is detected, the LTC4274 outputs a 2-Event classification to signal to the PD that it is a valid IEEE 802.3at PSE and can supply the high power. Disconnect The LTC4274 performs DC disconnect. In order for a PD to remain on, it must display a maintain power signature by drawing more than 10mA. If the port load is less than 5mA for 350ms (typ), then the LTC4274 will remove power from the port. Overcurrent The LTC4274 in AUTO pin high mode detects, classifies and sets the current limits according to the classification results. Refer to Table 1 for the overcurrent limits with a 0.25Ω sense resistor. SHDN and RESET Pushbuttons The DC1567B has pushbuttons to the LTC4274 SHDN, RESET and DGND pins. Momentarily tying SHDN to DGND will shut down the port if it is on and disable detection preventing the port from turning on again. Momentarily tying RESET to DGND will reset the LTC4274 to its AUTO pin high mode state without having to cycle power. dc1567bfa DEMO MANUAL DC1567B Surge Protection Ethernet ports can be subject to significant cable surge events. To keep PoE voltages below a safe level and protect the application against damage, protection components are required at the main supply, at the LTC4274 supply pins and at the port. The LTC4274 requires a 10Ω, 0805 resistor (R10) in series from supply AGND to the LTC4274 AGND pin. Across the LTC4274 AGND pin and VEE pin are an SMAJ58A, 58V TVS (D3) and a 1μF, 100V bypass capacitor (C4). These components must be placed close to the LTC4266 pins. Bulk transient voltage suppression devices and bulk capacitance are required across the main PoE supply and should be sized to accommodate system level surge requirements. The DC1567B diode D2 and capacitor C2 are example components for this protection at the main PoE supply. The port requires a pair of S1B clamp diodes: one from OUT to supply AGND and one from OUT to supply VEE. The diodes at the ports steer harmful surges into the supply rails where they are absorbed by the surge suppressors and the VEE bypass capacitance. The layout of these paths must be low impedance. dc1567bfa 5 A B C E2 D2 SMBJ58A VEE _ 55V + 1 2 E1 5 + VEE C2 4.7uF 100V R5 750k 1 CMHZ4687-4.3V D1 AGND 2 1 R10 10 0805 1 2 2 3 MAIN PS INPUTS R17 10k R18 10k Q2 CMPTA92 ORANGE MAIN PS D6 R13 1k 1 2 2 R14 0 10 15 16 17 36 4 DGND DGND DGND DGND MID AUTO D3 SMAJ58A TP1 DGND C1 0.1uF R11 0 VDD 13 VDD R12 0 33 U1 SHDN SW1 RESET TP2 R15 0 C4 1uF 100V R16 0 1 RS2 RS3 1 1 1 RS1 RS4 TP3 SDAOUT SW2 LTC4274CUHF 1 2 14 18 MSD 34 SHDN AGND 35 RESET 7 INT INT 38 SCL 37 19 22 25 26 27 39 VEE VEE VEE VEE VEE VEE 3 SDAIN 1 SDAOUT SENSE 4 2 8 2 9 11 12 20 21 23 24 28 29 J2 1 2 3 4 5 6 7 8 R8 100k VEE 1 D5 S1B D4 S1B 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. E3 VPORT- E4 C3 1000pF 2kV R3 75 R4 75 R2 75 R1 75 ECO 20 19 17 18 16 15 13 14 9 7 8 2 1 3 5 6 4 10 12 11 1 2 SCALE = NONE DATE: N/A SIZE DESCRIPTION REBUILD WITH CHANGE 1 DILIAN R. SHIELD2 SHIELD1 8 7 5 4 6 3 2 1 22 IC NO. Thursday, July 09, 2015 1 DEMO CIRCUIT 1567B SHEET 1 OF SINGLE PORT IEEE 802.3at PSE LTC4274CUHF 1 1 REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only J1 0838-1X1T-W7 1000pF 2kV 4 X 12nF 100V 4 X 75 Ohms TECHNOLOGY LED2Y LED2X LED1C LED1A VC2B VC2A VC1A VC1B TRD4- TRCT4 TRD4+ TRD3- TRCT3 TRD3+ TRD2- TRCT2 TRD2+ TRD1- TRCT1 TRD1+ 21 DATE 07-09-15 APPROVED REVISION HISTORY DATA AND POWER TO PD REV DILIAN R. TITLE: SCHEMATIC KIM T. APPROVALS VEE VPORT+ FB2 Q10 CMPTA42 RLED 12k 1/4W 2 FB1 C5 0.22uF 100V SS-7188S-A-NF 10 9 CUSTOMER NOTICE Q1 PHT6NQ10T 3 DNC NC NC NC NC NC NC NC NC NC NC DATA FROM PHY LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED APP ENG. CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 30 6 AD0 1 AD2 4 AD3 5 AD1 GATE 31 1 OUT 32 3 1 2 1 2 4 3 6 2 D 5 A B C D DEMO MANUAL DC1567B Schematic Diagram dc1567bfa DEMO MANUAL DC1567B PCB Layout and Film Top Assembly Top Side dc1567bfa 7 DEMO MANUAL DC1567B pcb layout and film Inner Layer 2 Inner Layer 3 8 dc1567bfa DEMO MANUAL DC1567B pcb layout and film Bottom Side Assembly Bottom dc1567bfa Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 9 DEMO MANUAL DC1567B DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. 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For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation 10 Linear Technology Corporation dc1567bfa LT 0915 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2010