LCP1521S Programmable transient voltage suppressor for SLIC protection Features Programmable transient suppressor Wide negative firing voltage range: VGn = -175 V max. Low dynamic switching voltages: VFP and VDGL Low gate triggering current: IGT = 5 mA max. Peak pulse current: IPP = 30 A (10/1000 s) Holding current: IH = 150 mA min. SO-8 LCP1521S Figure 1. Functional diagram Benefits A TrisilTM is not subject to ageing and provides a fail safe mode in short circuit for a better level of protection. Trisils are used to ensure equipment meets various standards such as UL60950, IEC 950 / CSA C22.2, UL1459 and FCC part 68. Trisils have UL94 V0 approved resin (Trisils are UL497B approved [file: E136224]). TIP 1 TIP Gn GND NC GND RING RING Description These devices have been especially designed to protect new high voltage, as well as classical SLICs, against transient overvoltages. Positive overvoltages are clamped by 2 diodes. Negative surges are suppressed by 2 thyristors, their breakdown voltage being referenced to -VBAT through the gate. These components present a very low gate triggering current (IGT) in order to reduce the current consumption on printed circuit board during the firing phase. TM: Trisil is a trademark of STMicroelectronics February 2012 Doc ID 16804 Rev 2 1/9 www.st.com 9 Characteristics 1 LCP1521S Characteristics Table 1. Standards compliance Standard Peak surge voltage Voltage waveform (V) Current waveform Minimum serial resistor to meet standard () (A) 2500 1000 2/10 s 10/1000 s 500 100 2/10 s 10/1000 s 12 24 5000 2/10 s 500 2/10 s 24 1500 2/10 s 100 2/10 s 0 ITU-T-K20/K21 6000 1500 10/700 s 150 37.5 5/310 s 110 0 ITU-T-K20 (IEC 61000-4-2) 8000 15000 1/60 ns IEC 61000-4-5 4000 4000 10/700 s 1.2/50 s 100 100 5/310 s 8/20 s 60 0 1500 800 10/160 s 10/560 s 200 100 10/160 s 10/560 s 22.5 15 1000 9/720 s 25 5/320 s 0 GR-1089 Core First level GR-1089 Core Second level GR-1089 Core Intra-building TIA-968-A, lightning surge type A TIA-968-A, lightning surge type B Table 2. Rth(j-a) ESD contact discharge ESD air discharge 0 0 Thermal resistances Symbol 2/9 Required peak current Parameter Junction to ambient Doc ID 16804 Rev 2 Value Unit 120 C/W LCP1521S Characteristics Table 3. Absolute ratings (Tamb = 25 C) Symbol Value Unit 10/1000 s 8/20 s 10/560 s 5/310 s 10/160 s 1/20 s 2/10 s 30 100 35 40 50 100 150 A ITSM t = 20 ms Non repetitive surge peak on-state current t = 200 ms (50 Hz sinusoidal) t=1s 18 10 7 A VGn Negative battery voltage range -175 V Tstg Tj Storage temperature range Operating junction temperature range -55 to +150 -40 to +150 C 260 C Peak pulse current IPP TL -40 C < Tamb < +85 C Maximum lead temperature for soldering during 10 s. Figure 2. Symbol IGT VFP VGT VF IRG IH VRG VDGL IPP IR VF C Parameter = = = = = = = = = = = = Electrical characteristics (definitions) I Parameter Gate triggering current Peak forward voltage LINE / GND Gate triggering voltage Forward drop voltage LINE /GND Reverse leakage current GATE / LINE Holding current Reverse voltage GATE / LINE Dynamic switching voltage GATE / LINE Peak pulse current Breakdown current Forward drop voltage LINE / GND Capacitance LINE /GND VR VF IR V IH IPP Figure 3. Pulse waveform % IPP Pulse waveform 10/1000 s: tr = 10 s tp = 1000 s 100 50 0 tr tp Doc ID 16804 Rev 2 3/9 Characteristics LCP1521S Table 4. Parameters related to the diode LINE / GND (Tamb = 25 C) Symbol Test conditions VF IF = 5 A VFP 10/700 s 1.2/50 s 2/10 s Table 5. 1.5 kV 1.5 kV 2.5 kV Max. Unit t = 500 s 3 V RS = 10 RS = 10 RS = 62 5 9 30 V Parameters related to the protection thyristors (Tamb = 25 C) Symbol Test conditions Min. Max. Unit 5 mA IGT VLINE = -48 V 0.1 IH VGn = -48 V 150 VGT at IGT IRG VRG = -175 V VRG = -175 V mA 2.5 V Tj = 25 C Tj = 85 C 5 50 A IPP = 30 A IPP = 30 A IPP = 38 A 7 10 25 V VGn = -48 V(1) VDGL 10/700 s 1.2/50 s 2/10 s 1.5 kV 1.5 kV 2.5 kV RS = 10 RS = 10 RS = 62 1. The oscillations with a time duration lower than 50 ns are not taken into account. Table 6. Parameters related to diode and protection thyristors (Tamb = 25 C) Symbol IR VGn / LINE = -1 V VGn / LINE = -1 V C VLINE = -50 V, VRMS = 1 V, F = 1 MHz VLINE = -2 V, VRMS = 1 V, F = 1 MHz Table 7. Symbol CG 4/9 Test conditions VLINE = -175 V VLINE = -175 V Typ. Tj = 25 C Tj = 85 C Max. Unit 5 50 A 15 35 pF Recommended gate capacitance Component Gate decoupling capacitance Doc ID 16804 Rev 2 Min. Typ. 100 220 Max. Unit nF LCP1521S Technical information Figure 4. LCP concept behavior Rs1 L1 TIP GND -Vbat V Tip ID1 IG T1 Th1 D1 Gn GND C Rs2 VRing RING L2 Figure 4 shows the classical protection circuit using the LCP crowbar concept. This topology has been developed to protect the new high voltage SLICs. It allows to program the negative firing threshold while the positive clamping value is fixed at GND. When a negative surge occurs on one wire (L1 for example) a current IG flows through the base of the transistor T1 and then injects a current in the gate of the thyristor Th1. Th1 fires and all the surge current flows through the ground. After the surge when the current flowing through Th1 becomes less negative than the holding current IH, then Th1 switches off. When a positive surge occurs on one wire (L1 for example) the diode D1 conducts and the surge current flows through the ground. Figure 5. Example of PCB layout based on LCP1521S protection 220 nF 2 Technical information To line side GND To SLIC side Figure 5 shows the classical PCB layout used to optimize line protection. The capacitor C is used to speed up the crowbar structure firing during the fast surge edges. This allows minimization of the dynamic breakover voltage at the SLIC Tip and Ring inputs during fast strikes. Note that this capacitor is generally present around the SLIC - Vbat pin. So to be efficient it has to be as close as possible from the LCP Gate pin and from the reference ground track (or plan) (see Figure 5). The optimized value for C is 220 nF. The series resistors Rs1 and Rs2 designed in Figure 4 represent the fuse resistors or the PTC which are mandatory to withstand the power contact or the power induction tests Doc ID 16804 Rev 2 5/9 Technical information LCP1521S imposed by the various country standards. Taking into account this fact the actual lightning surge current flowing through the LCP is equal to: I surge = V surge / (Rg + Rs) With: V surge = peak surge voltage imposed by the standard. Rg = series resistor of the surge generator Rs = series resistor of the line card (e.g. PTC) e.g. For a line card with 30 of series resistors which has to be qualified under GR1089 Core 1000V 10/1000 s surge, the actual current through the LCP is equal to: I surge = 1000 / (10 + 30) = 25 A The LCP is particularly optimized for the new telecom applications such as the fiber in the loop, the WLL, the remote central office. In this case, the operating voltages are smaller than in the classical system. This makes the high voltage SLICs particularly suitable. The schematics of Figure 6 give the most frequent topology used for these applications. Figure 6. Protection of high voltage SLIC -Vbat Rs (*) TIP TIP Gn GND 220nF GND GND Line SLIC RING Rs (*) RING LCP1521S Line card Rs (*) = PTC or fuse resistor Figure 7. Surge peak current versus overload Figure 8. duration Relative variation of holding current versus junction temperature ITSM(A) 24 IH[Tj] / IH[Tj=25C] F=50Hz Tj initial=25C 1.3 20 1.2 16 1.1 12 1 8 0.9 0.8 4 Tj(C) t(s) 0.7 -40 0 1.E-02 6/9 1.E-01 1.E+00 1.E+01 1.E+02 -30 1.E+03 Doc ID 16804 Rev 2 -20 -10 0 10 20 30 40 50 60 70 80 90 LCP1521S 3 Package information Package information Epoxy meets UL94,V0 Lead-free package In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK(R) packages, depending on their level of environmental compliance. ECOPACK(R) specifications, grade definitions and product status are available at: www.st.com. ECOPACK(R) is an ST trademark. Table 8. SO-8 dimensions Dimensions Ref. Millimeters Min. Typ. A C (Seating Plane) ccc C A2 0.25mm (Gage Plane) C 1 0.1 Max. 0.069 0.25 0.004 A2 1.25 b k 0.28 0.48 0.011 0.019 C 0.17 0.23 0.007 0.009 0.010 D 4.80 5.00 0.189 0.193 0.197 0.049 E 4.90 E 5.80 6.00 6.20 0.228 0.236 0.244 E1 3.80 3.90 4.00 0.150 0.154 0.157 5 e 4 1.27 h 0.25 L 0.40 L1 k ccc Figure 9. Typ. 1.75 A1 D E1 Min. h x 45 L1 8 Max. L A1 e b A Inches 0.050 0.50 0.010 1.27 0.016 1.04 0.020 0.050 0.041 0 8 0.10 0 8 0.004 Foot print recommendations 6.8 (0.268) 0.6 (0.024) 4.2 (0.165) 1.27 (0.050) Doc ID 16804 Rev 2 7/9 Ordering information 4 LCP1521S Ordering information Table 9. Ordering information Order code Marking LCP1521S CP152S LCP1521SRL (1) Package Weight SO-8 0.078 g Base qty Delivery mode 100 Tube 2500 Tape and reel CP152S 1. Preferred device 5 Revision history Table 10. 8/9 Document revision history Date Revision Changes 20-Nov-2009 1 First issue. 23-Feb-2012 2 Standardized nomenclature for Gn. Doc ID 16804 Rev 2 LCP1521S Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries ("ST") reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST's terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. 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