Power over Ethernet protection PEP01-5841 A new Transil array to protect power supplies Power over Ethernet eliminates the need for external power supplies on the customer’s side as they are included in routers and are able to deliver up to 30 W under 48 V (POE+) according to IEEE 802.3af. Power is transported using two pairs in an Ethernet cable. As for all cables, they are subject to surges and must be protected against electrostatic discharge (ESD) and electrical overstress (EOS). Key features PEP01-5841 The PEP01-5841 embeds 4 protection units that are fine tuned in voltage and current for POE applications, and 4 capacitances to filter high-frequency disturbances. Temperature capability The PEP01-5841 is specified with IRmax= 1 µA at 85 °C (telecommunication temperature) and 0.2 µA at 25 °C. TJmax is compliant with the industrial standard for tough environments: 150 °C Surge capability To be compliant with IEC 61000-4-5 level 2 (1 kV), the PEP01-5841 is specified at 24 A 8/20 µs and the VCL has been improved to be compatible with 100 V PMOS and PSE controller technologies. VBRmin has been defined to take into account tolerance on power supply voltage and can be calculated whatever the temperature is using (aT): VBRmin @ TJ = VBRmin @ 25°C x (1 + aT x (TJ – 25)) Dynamic resistance (RD) is given to calculate VCLmax at other current surge values, for instance at 12 A (IEC 61000-4-5 level 1,500 V): VCLmax = RD x IPP + VBRmax VCLmax = 85.6 V The PEP01-5841 is able to protect against ESD up to 30 kV according to IEC 61000-4-2. www.st.com/protection Key benefits Compliant with IEC 61000-4-5 level 2 (1 kV – 24 A 8/20 µs) Compatible with PMOS and PSE controller voltages (maximum clamping voltage: 100 V) Low leakage current in telecommunication temperature range 4 protection units/filtering in 1 S0-8 package (55% space saving) Target applications Power over Ethernet (POE and POE+) Package The PEP01-5841 is packaged in an SO8 (28 mm²) which provides 55% space saving versus 4 x SMA (Transils) + 4 x 0306 capacitances. Relevant standards As an Ethernet cable is a dataline, the impedance of the IEC 61000-4-5 surge generator is 42 W. Surge level is either 500 V or 1 kV, leading to surge currents of 12 A or 24 A respectively (8/20 µs). The second standard is IEC 61000-4-2, which defines ESD surges. State-of-the-art protection Protection is achieved using the SMAJ58A and SMBJ58A Transils specified with VCLmax = 121 V, which is higher than the maximum admissible voltage of PMOS and PSE controllers. Application schematic PSE controller - 48 V PEP01-5841 © STMicroelectronics - April 2009 - Printed in Italy - All rights reserved The STMicroelectronics corporate logo is a registered trademark of the STMicroelectronics group of companies. Transil, Trisil and Transky are trademarks of STMicroelectronics. All other names are the property of their respective owners. For more information on ST products and solutions, visit www.st.com Order code: FLPEP010409