SI01-06 Surging Ideas TVS Diode Application Note PROTECTION PRODUCTS LC03-3.3 Testing to derived current waveform has a duration of 2/10µs. Since this is a test using a voltage source, the impedance of the unit under test can decrease the amount of current actually seen by the circuit. The test performed on Semtech’s LC03-3.3 is a current source test. The purpose of using a current source tester is to insure that the current through the device is actually 100A. This provides for a worse case scenario and insures that the part will operate under worse case conditions. In addition, the test performed is an 8x20µs surge. The 8/20µs pulse is longer in duration than the 2/10µs. This means the test performed on the devices is actually a higher energy pulse than required by the Bellcore intra-building standard. Figure 1 shows the test setup for common mode. Figure 2 shows the test setup for differential mode. Bellcore 1089 Intra-building Test Setup The intra-building lightning surge required by Bellcore 1089 is defined by a double exponential waveform. For testing purposes this is achieved with a voltage source and a resistor/capacitor network. The lines are tested in both metallic (line-to-line) and longitudinal (line-to-ground) configuration. For metallic mode, the standard calls for an 800V (open circuit voltage) surge with a 100A minimum (short circuit current) coming out of the tester. For a longitudinal mode, it calls for a 1500V (open circuit voltage) surge with a 100A (short circuit current) minimum coming out of the tester. The 8x20 us Current Source tester 1 8 2 7 3 6 4 5 Figure 1 . Common Mode 8x20 us Current Source tester 1 8 2 7 3 6 4 5 Figure 2 . Differential Mode Revision 2/4/2002 1 www.semtech.com SI01-06 Surging Ideas TVS Diode Application Note PROTECTION PRODUCTS Test Results voltage of the LC03-3.3 from pin 1 to 2 during a 100A 8/20µs surge. The part is electrically tested after each surge to verify that the device is still operative. Figure 4 shows the typical clamping curve of the LC03-3.3 during an 8/20µs surge from 1 to 100A. Two curves are shown, line to line (differential mode) and line to ground (common mode). An oscilloscope was used to display the voltage across the LC03-3.3 during a 100A 8/20µs double exponential pulse. Figure 1 is the configuration of the test performed. The current output by the tester is monitored on Ch1. The current ratio is 20A/100mV. The voltage between pin 1 and 2 of the LC03-3.3 is monitored on Ch2. Figure 3 shows the clamping Figure 3. LC03-3.3 Clamping Voltage During 100A 8x20µs Surge 20 Clamping Voltage (V) Line-To-Line 15 10 Line-To-Ground Waveform Parameters: tr = 8µs td = 20µs 5 0 0 20 40 60 80 100 Peak Pulse Current (A) Figure 4. LC03-3.3 Typical Clamping Voltage vs. Peak Pulse Current 2002 Semtech Corp. 2 www.semtech.com