protection products 1 www.semtech.com protection products si01-15 surging ideas tvs diode application note revision 02/04/2002 DVI protection the industry?s demand for high-resolution flat panels requires more complex digital and analog solutions in a dense area. the small geometry?s of the digital-visual interface (DVI) graphic chip makes it more susceptible to electrostatic discharges (esd) and cable discharge events (cde). the industry esd standard is iec61000- 4-2. it requires the system to withstand 8kv contact and 15kv air esd. transient protection of a DVI port can be challenging. digital-visual interfaces can often transmit and receive at a rate equal to or above 1gbps. the high-speed data transmission requires the protection device to have low capacitance to maintain signal integrity and low clamping voltage to reduce stress on the protected ic. the srv05-4 tvs array is specifically designed for this application. the srv05-4 has a low capacitance of 3pf from any i/o pin (pin 1,3,4 or 6) to ground (pin 2) or 1.5pf from any i/o pin to i/o pin. the insertion loss characteristic of the srv05-4 is shown in figure 2. the graph shows that the device has a low insertion loss of 0.4db at 1ghz (i/o to ground). the srv05-4 is also designed to withstand the energy of a 15kv air and 8kv contact esd event. figure 3 shows that the srv05-4 clamps an 8kv contact esd surge to less than 20v. the srv05-4 will also protect the DVI graphic chip against cde. figure 4 shows how to design the srv05-4 into the DVI circuit on the flat panel display and in a pc graphic card. the srv05-4 is configured to provide common mode and differential mode protection. the internal tvs of the srv05-4 acts as a 5 volt reference. the power pin of the DVI circuit does not come out through the connector and is not subjected to external esd pulse; therefore, pin 5 should be left unconnected. connecting pin 5 to vcc of the DVI circuit may result in damage to the chip from esd current. figure 1 - srv05-4 schematic 3 db/ ch1 s21 log ref 0 db start .030 000 mhz stop 3 000 . 000 000 mhz figure 2 - srv05-4 insertion loss figure 3 - srv05-4 8kv contact esd response
2 ? 2002 semtech corp. www.semtech.com protection products protection products si01-15 surging ideas tvs diode application note figure 4 - DVI protection
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