ITAxxB3 Bidirectional Transil™ array for data line protection Features ■ High surge capability Transil array: IPP = 40 A (8/20 µs) ■ Peak pulse power: 300 W (8/20 µs) ■ Separated Input - Output ■ Up to 9 bidirectional Transil functions ■ Low clamping factor (VCL/VBR) at high current level ■ Low leakage current ■ ESD protection up to 15 kV Complies with the following standards ■ ■ IEC 61000-4-2 level 4 – 15 kV (air discharge) – 8 kV (contact discharge) MIL STD 883G- Method 3015-7: class 3B – 25 kV (human body model) Applications Differential data transmission lines protection, such as : ■ RS-232 ■ RS-423 ■ RS-422 ■ RS-485 SO-20 Description Transil diode arrays provide high overvoltage protection by clamping action. Their instantaneous response to transient overvoltages makes them particularly suited to protect voltage sensitive devices such as MOS technology and low voltage supplied IC’s. The ITA series combines high surge capability against energetic pulses with high voltage performance against ESD. The separated input/output configuration of the device ensures improved protection against very fast transient overvoltage like ESD by elimination of the spikes induced by parasitic inductances created by external wiring. Figure 1. GND 1 20 GND INPUT 2 19 OUTPUT INPUT 3 18 OUTPUT INPUT 4 17 OUTPUT INPUT 5 16 OUTPUT INPUT 6 15 OUTPUT INPUT 7 14 OUTPUT INPUT 8 13 OUTPUT INPUT 9 12 OUTPUT GND 10 TM: Transil is a trademark of STMicroelectronics November 2007 Functional diagram Rev 2 11 GND 1/8 www.st.com 8 Characteristics ITAxxB3 1 Characteristics Table 1. Absolute ratings (Tamb = 25 °C) Symbol PPP IPP Parameter Peak pulse power (8/20 µs)(1) Peak pulse current (8/20 µs) Unit Tj initial = Tamb 300 W Tj initial = Tamb 40 A 2 I t Wire I t value 0.6 A2s Tj Maximum operating junction temperature 125 °C -55 to +150 °C 260 °C Tstg TL 2 (1) Value (1) Storage temperature range Maximum lead temperature for soldering during 10 s 1. For surges greater than the specified maximum value, the I/O will first present a short-circuit and after an open circuit caused by the wire melting. Table 2. Electrical characteristics (Tamb = 25 °C) Symbol Parameter I IPP VRM Stand-off voltage VBR Breakdown voltage VCL Clamping voltage IRM Leakage current IPP Peak pulse current αT Voltage temperature coefficient VF Forward voltage drop C Capacitance VBR Order code IRM VRM @ IR min. IRM @ VCL max. @ IPP 8/20 µs (1) (1) VCL max. @ IPP 8/20 µs V αT C max. max. (1) (2) V mA µA V V A V A 10-4/°C pF ITA6V5B3 6.5 1 10 5 9.5 10 121 25 4 1100 ITA18B3 18 1 4 15 21 10 26 25 9 500 ITA25B3 25 1 4 24 31 10 36 25 12 420 1. Between I/O pin and ground. 2. Between two input pins at 0 V Bias, F = 1 MHz. 2/8 VRM VCL VBR ITAxxB3 Characteristics Figure 2. Pulse waveform Figure 3. Typical peak pulse power versus exponential pulse duration PPP(W) %IPP 1E+04 Tj initial=25°C ITA25B3 8 µs 100 ITA18B3 1E+03 Pulse waveform 8/20 µs ITA6V5B3 50 1E+02 0 t 20 µs tP(ms) expo 1E+01 1E-03 Figure 4. Clamping voltage versus peak pulse current (exponential waveform 8/20 µs) Figure 5. VCL(V) 1E-02 1E-01 1E+00 1E+01 1E+02 Peak current IDC inducing open circuit of the wire for one input/output versus pulse duration (typical values) IDC(A) 1E+03 1E+03 %IPP Tj initial=25°C Exponential waveform 100 50 0 1E+02 tr t tp 1E+02 ITA25B3 ITA18B3 1E+01 1E+01 ITA6V5B3 IPP(A) 1E+00 1E-01 Figure 6. 1E+00 tP(ms) 1E+00 1E+01 1E-02 1E+02 Junction capacitance versus reverse applied voltage for one input/output (typical values) Figure 7. 1E-01 1E+00 1E+01 Relative variation of leakage current versus junction temperature IR(Tj) IR(Tj=25°C) C(pF) 1E+03 ITA6V5B3 Tj=25°C F=1MHz 5E+3 1E+3 VR=VRM 1E+2 ITA18B3 1E+1 ITA25B3 1E+0 Tj(°C) VR(V) 1E+02 1E+00 1E+01 1E+02 1E-1 0 25 50 75 100 125 150 3/8 Application information 2 ITAxxB3 Application information This monolithic Transil Array is based on 610 unidirectional Transils with a common cathode and can be configurated to offer up to 9 bidirectional functions. This imposes a maximum differential voltage between 2 input pins (see Table 3). Table 3. Maximum differential voltages Order code Maximum differential voltage between two input pins at 25°C ITA6V5B3 ± 3.5 v ITA18B3 ± 9.0 v ITA25B3 ± 12.5 v Figure 8. RS-232 junction (typical application) TX RX RTS CTS DTR DSR CARRIER DET. AUX GND 2.1 Design advantage of ITAxxB3 used with 4-point structure The ITAxxxB3 has been designed with a 4-point structure Figure 9. The 4 point structure (separated Input/output) to efficiently protect against disturbances with very high di/dt rates, such as ESD. Chip The purpose of this 4-point structure is to eliminate the Output 1 Input 1 overvoltage introduced by the parasitic inductances of the BE di/dt wiring (Ldi/dt). U TO ED T CE EC I V T GND GND Efficient protection depends not only on the component DE RO P itself, but also on the circuit layout. The drawing given in figure 9 shows the layout to be used in order to take advantage of the 4-point structure of the ITAxxxB3. With this layout, each line to be protected passes through the protection device. In this way, it realizes an interface between the data line and the circuit to be protected, guaranteeing an isolation between its inputs and outputs. 4/8 ITAxxB3 3 Ordering information scheme Ordering information scheme Figure 10. Ordering information scheme ITA 25 B 3 RL Integrated Transil Array Breakdown Voltage (min) 25 = 25 Volt Type of lines protected B = Bidirectional Package 3 = SO-20 Packaging RL = Tape and reel Blank = Tube 5/8 Package information 4 ITAxxB3 Package information ● Epoxy meets UL94, V0 In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. Table 4. SO-20 dimensions Dimensions Ref. Millimeters Min. D hx45° A K B e L A1 E H C Typ. Inches Max. Min. Max. A 2.35 2.65 0.092 0.104 A1 0.10 0.30 0.004 0.008 B 0.33 0.51 0.013 0.020 C 0.23 0.32 0.009 0.013 D 12.6 13.0 0.484 0.512 E 7.40 7.60 0.291 0.299 e 1.27 0.050 H 10.0 10.65 0.394 0.419 h 0.25 0.75 0.010 0.029 L 0.40 1.27 0.016 0.050 K 8° (max) Figure 11. SO-20 footprint (dimensions in mm) 11.2 8.5 1.27 6/8 Typ. 0.6 ITAxxB3 5 Ordering Information Ordering Information Table 5. 6 Ordering information Order code Marking ITA6V5B3 Package Base qty Delivery mode ITA6V5B3 1000 Tube ITA18B3 ITA18B3 1000 Tube ITA18B3RL ITA18B3 1000 Tape and reel ITA25B3 ITA25B3 1000 Tube ITA25B3RL ITA25B3 1000 Tape and reel SO-20 Weight 0.55 g Revision history Table 6. Document revision history Date Revision Changes 13-Dec-2004 1 Initial release. 07-Nov-2007 2 Reformatted to current standards. Updated leakage current values in Table 2 Updated pulse waveform parameters in Figure 2. 7/8 ITAxxB3 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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