LC04-12

Dual Low Capacitance TVS Array for Telecom Line-Card Applications PROTECTION PROTECTION PRODUCTS Description The LC04-12 has been specifically designed to protect sensitive components which are connected to highspeed telecommunications lines from over voltages caused by lightning, ESD (electrostatic discharge), and EFT (electrical fast transients). The device is in a JEDEC SO-16 NB package. It is designed to provide metallic (Tip to Ring) or common mode (Tip to Ground & Ring to Ground) surge protection for up to two Tip and Ring pairs. The low capacitance topology means signal integrity is preserved on high-speed lines. The high surge capability (600W, tp=10/1000µs) makes the LC04-12 suitable for telecommunications systems operating in harsh transient environments. The LC04-12 is designed to meet the lightning surge requirements of Bellcore GR1089(intra-building), ITU K.20, and IEC 61000-4-5. The features of the LC04-12 are ideal for protecting ADSL, RS-232, RS-423, RS-422, and V.90 interfaces. LC04-12 Features u Transient protection for high-speed data lines to Bellcore GR 1089 IPP=100A (2/10µs) ITU K.20 IPP=100A (5/310µs) IEC 61000-4-2 (ESD) 15kV (air), 8kV (contact) IEC 61000-4-5 (Lightning) IPP=100A (8/20µs) Protects two tip and ring line pairs Low capacitance for high-speed interfaces High surge capability Low clamping voltage Solid-state silicon avalanche technology u u u u u Mechanical Characteristics u u u u u u u u u JEDEC SO-16 package Molding compound flammability rating: UL 94V-0 Marking : Part number, date code, logo Packaging : Tube or Tape and Reel per EIA 481 Applications ADSL/HDSL RS-232 & RS-423 V.90 WAN/LAN Equipment Cable Modems Circuit Diagram Schematic & PIN Configuration TIP RING SO-16 (Top View) Revision 9/2000 1 www.semtech.com LC04-12 PROTECTION PRODUCTS Absolute Maximum Rating R ating Peak Pulse Pow er (tp = 10/1000µs) Peak Pulse Current (tp = 10/1000 µ s) Peak Pulse Current (tp = 8/20µs) Lead Soldering Temp erature Op erating Temp erature Storage Temp erature Symbo l Pp k I PP I PP TL TJ TSTG Value 600 25 100 260 (10 sec.) -55 to +125 -55 to +150 Units Watts A A °C °C °C Electrical Characteristics LC04-12 Par ame te r Reverse Stand-Off Voltage Reverse Breakdow n Voltage Reverse Leakage Current Clamp ing Voltage Clamp ing Voltage Junction Cap acitance Symbo l VRWM V BR IR VC VC Cj It = 1mA VRWM = 12V, T=25°C IPP = 10A, tp = 10/1000µs IPP = 25A, tp = 10/1000µs Each Line V R = 0V, f = 1MHz 13.3 2 19.5 24 15 Co nd itio ns Minimum Typ ical Maximum 12 Units V V µA V V pF ã 2000 Semtech Corp. 2 www.semtech.com LC04-12 PROTECTION PRODUCTS Typical Characteristics Non-Repetitive Peak Pulse Power vs. Pulse Time 100 110 100 Power Derating Curve 90 % of Rated Power or IPP 80 70 60 50 40 30 20 10 Peak Pulse Power - PPP (kW) 10 1 0.1 0.1 1 10 Pulse Duration - tp (µs) 100 1000 0 0 25 50 75 100 o 125 150 Ambient Temperature - TA ( C) Pulse Waveform 110 100 90 80 Percent of IPP 70 60 50 40 30 20 10 0 0 5 10 15 Time (µs) 20 25 30 0 25 Clamping Voltage vs. Peak Pulse Current (tp=8/20ms) e -t Clamping Voltage - Vc (V) Waveform Parameters: tr = 8µs td = 20µs 20 15 td = IPP/2 10 Waveform Parameters: tr = 8µs td = 20µs 0 20 40 60 80 100 120 140 160 5 Peak Pulse Current - Ipp (A) 30 25 20 15 10 5 0 0 Clamping Voltage vs. Peak Pulse Current (tp=10/1000m s) Clamping Voltage - Vc (V) Waveform Parameters: tr = 10µs td = 1000µs 5 10 15 20 25 30 Peak Pulse Current - Ipp (A) ã 2000 Semtech Corp. 3 www.semtech.com LC04-12 PROTECTION PRODUCTS Applications Information Figure 1 - Connection for Differential (Line-to-Line) Protection of two Tip/Ring Line Pairs Device Connection Options The LC04-12 is designed to protect up to four highspeed data lines (two differential pairs) from transient over-voltages which result from lightning and ESD. Differential protection of two line pairs is achieved by connecting the device as follows (Figure 1): Pins 1-4 are connected to line 1 of the first pair (i.e. Tip 1) and pins 13-16 are connected to line 2 of the first pair (i.e. Ring 1). Pins 5-8 are connected to line 1 of the second pair (i.e. Tip 2) and pins 9-12 are connected to line two of the second pair (i.e. Ring 2). Common mode protection of one line pair is achieved by connecting the device as shown in Figure 2. The protected lines are connected at pins 1-4 and pins 912. connection to ground is made at pins 5-8 and 1316. optionally, the lines may be connected at pins 1-4 and 5-8 with pins 9-16 being connected to ground. All pins should be connected for best results. Minimize parasitic inductance in the protection circuit path by keeping the trace length between the protected line and the LC04-12 as short as possible. Ground connections should be made directly to the ground plane. ADSL Protection Configuring The LC04-12 for Remote Terminal ADSL Applications A typical ADSL protection circuit for remote terminals is shown in Figure 3. The LC04-12 is connected between Tip & Ring on the transmit and receive line pairs. It provides protection to common mode (line-to-ground) lightning and ESD surges. It is designed to meet the intra-building requirements of Bellcore GR-1089. To complete the protection circuit, the LCDA12C-1 is employed as the IC side protection element. This device helps prevent the transceiver from latching up by providing fine clamping of transients that are coupled through the transformer. TIP 1 RING 1 TIP 2 RING 2 Figure 2 - Connection for Common Mode (Line-toGround) Protection of one Tip/Ring Line Pair TIP GND GND RING ã 2000 Semtech Corp. 4 www.semtech.com LC04-12 PROTECTION PRODUCTS Applications Information (Continued) Configuring The LC04-12 for Central Office ADSL Applications For Central Office applications, the LC04-12 can be configured for operation to 24V with the addition of two external steering diodes. This is accomplished by connecting two adjacent legs of the LC04-12 in series and adding the steering diodes as shown in Figure 4. Each of the TVS diodes has a working voltage of 12V. Since the voltages are additive when series connected, the device will have a working voltage of 24V. The power rating of the device is effectively doubled since the surge current capability remains unchanged. During positive duration transients, the internal TVS diodes of the LC04-12 will be reversed biased when the line voltage exceeds 24V. Transient current will flow through the LC04-12 to ground. For negative duration transient, the external steering diodes (D1 & D2) will be forward biased when the voltage exceeds the forward voltage (VF) of the device. The steering diodes are required to insure that the internal compensation diodes of the LC04-12 are not reverse biased as this would result in their destruction. The ES1A ultrafast rectifiers have been found to work well in this application. These devices will survive the Bellcore 1089 (intra-building) and ITU K.20/K.21 surges and have a repetitive reverse voltage rating of 50V, and a typical junction capacitance of 10pF. The total capacitance seen by the line will typically be