L3121B

® L3121B PROGRAMMABLE TRANSIENT VOLTAGE SUPPRESSOR FOR SLIC PROTECTION Application Specific Discretes A.S.D.TM FEATURES BIDIRECTIONAL FUNCTION WITH VOLTAGE PROGRAMMABILITY IN BOTH POSITIVE AND NEGATIVE POLARITIES. PROGRAMMABLE BREAKDOWN VOLTAGE UP TO 100 V. HOLDING CURRENT = 150 mA min. HIGH SURGE CURRENT CAPABILITY. IPP = 100A , 10/1000 µs SIP4 DESCRIPTION This device has been especially designed to protect a subscriber line interface circuit (SLIC) with an integrated ring generator. Used with the recommended application circuit, each line (TIP and RING) is protected against positive and negative surges. In the positive polarity, the breakdown voltage is referenced to the + VB , and in the negative polarity, the breakdown voltage is referenced to the -Vbat . Its high surge current capability makes the L3121B a reliable protectiondevice for very exposed equipment, or when series resistors are very low. SCHEMATIC DIAGRAM Line Gate P Gate N GND CONNECTION DIAGRAM May 1999 - Ed:4A 1/7 L3121B Peak Surge Voltage (V) 4000 4000 4000 level 4 level 4 1500 800 1000 2500 1000 5000 Voltage Waveform (µs) 10/700 10/700 1.2/50 10/700 1.2/50 10/160 10/560 9/720 2/10 10/1000 2/10 Current Waveform (µs) 5/310 5/310 1/20 5/310 8/20 10/160 10/560 5/320 2/10 10/1000 2/10 Admissible Ipp (A) 100 100 100 100 100 200 100 25 250 100 250 Necessary Resistor (Ω) 10 COMPLIES WITH THE FOLLOWING STANDARDS: ITU-T K20 VDE0433 VDE0878 IEC1000-4-5 FCC Part 68, lightning surge type A FCC Part 68, ligh...