1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T K.103 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2015) SERIES K: PROTECTION AGAINST INTERFERENCE Surge protective component application guide Silicon PN junction components Recommendation ITU-T K.103 Rec. ITU-T K.1
2、03 (03/2015) i Recommendation ITU-T K.103 Surge protective component application guide Silicon PN junction components Summary Recommendation ITU-T K.103 describes the construction, characteristics, ratings and application examples of surge protective components (SPCs), having one or two silicon PN j
3、unctions, intended for the protection of exchange and outdoor equipment, subscriber or customer equipment and telecommunication lines from surges. The PN junction technologies covered are: Zener breakdown, avalanche breakdown, fold-back, punch-through and rectification. History Edition Recommendatio
4、n Approval Study Group Unique ID* 1.0 ITU-T K.103 2015-03-01 5 11.1002/1000/12423 Keywords Application circuits, array, avalanche, electrical characteristics, electrical ratings, fold-back, punch-through, rectification, Zener. _ * To access the Recommendation, type the URL http:/handle.itu.int/ in t
5、he address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T K.103 (03/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications
6、, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications o
7、n a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid d
8、own in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunicatio
9、n administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandato
10、ry provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws atte
11、ntion to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or other
12、s outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent
13、the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T K.103 (03/2015) ii
14、i Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 3 6 Construction 3 6.1 Packaging . 3 6.2 Semiconductor junction structure and electrical properties . 4 7 Char
15、acteristics . 10 7.1 Stand-off or maximum reverse working voltage, VRWM . 11 7.2 Breakdown voltage, V(BR) . 11 7.3 Clamping voltage, VC 12 7.4 Punch-through voltage V(PT) . 13 7.5 Snap back voltage V(SB) 13 7.6 Forward biased PN junction voltage, VF . 13 7.7 Junction capacitance, CJ . 15 7.8 Package
16、 inductance 17 8 Ratings 17 8.1 Peak pulse current, IPP . 17 8.2 Maximum peak pulse power, PPPM 19 8.3 Power dissipation, PD 19 9 Application examples . 20 9.1 Series connection 20 9.2 Parallel connection . 21 9.3 DC supply protection 21 9.4 Power frequency protection 23 9.5 Signal protection . 24 B
17、ibliography. 29 Rec. ITU-T K.103 (03/2015) 1 Recommendation ITU-T K.103 Surge protective component application guide Silicon PN junction components 1 Scope This Recommendation in the surge protective component application guide series covers voltage limiting components, having one or two silicon PN
18、junctions. These surge protective components (SPCs) are clamping type overvoltage protectors b-ITU-T K.96. Components covered in this Recommendation use the following PN junction technologies: Zener breakdown, avalanche breakdown, fold-back, punch-through and rectification. Guidance is given on cons
19、truction, characteristics, ratings and application examples. 2 References This Recommendation does not contain any normative references. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 avalanche breakdown (of a PN junction) b-IEC 60050-
20、521: Breakdown that is caused by the cumulative multiplication of charge carriers in a semiconductor under the action of a strong electric field, which causes some carriers to gain enough energy to liberate new hole-electron pairs by ionization. 3.1.2 bidirectional transistor b-IEC 60050-521: Transi
21、stor, which has substantially the same electrical characteristics when the terminals normally designated as emitter and collector are interchanged. 3.1.3 bipolar junction transistor b-IEC 60050-521: Transistor having at least two junctions and whose functioning depends on both majority carriers and
22、minority carriers. 3.1.4 breakdown (of a reverse-biased PN junction) b-IEC 60050-521: Phenomenon, the initiation of which is observed as a transition from a state of high dynamic resistance to a state of substantially lower dynamic resistance for increasing magnitude of reverse current. 3.1.5 common
23、 mode conversion b-ITU-T K.96: Process by which a differential mode electrical signal is produced in response to a common mode electrical signal. 3.1.6 common mode surge b-ITU-T K.96: Surge appearing equally on all conductors of a group at a given location. NOTE 1 The reference point for common mode
24、 surge voltage measurement can be a chassis terminal, or a local earth/ground point. NOTE 2 Common mode surge is also known as longitudinal surge or asymmetrical surge. 3.1.7 differential mode surge b-ITU-T K.96: Surge occurring between any two conductors or two groups of conductors at a given locat
25、ion. NOTE 1 The surge source maybe be floating, without a reference point or connected to reference point, such as a chassis terminal, or a local earth/ground point. NOTE 2 Differential mode surge is also known as metallic surge or transverse surge or symmetrical surge or normal surge. 3.1.8 diode (
26、semiconductor) b-IEC 60050-521: Two-terminal semiconductor device having an asymmetrical voltage-current characteristic. 2 Rec. ITU-T K.103 (03/2015) NOTE Unless otherwise qualified, this term usually means a device with the voltage-current characteristic typical of a single PN junction. 3.1.9 fold-
27、back breakdown (of a bidirectional transistor) b-ITU-T K.96: Re-entrant breakdown characteristic caused by transistor action producing a region of negative dynamic resistance before reverting back to a low positive dynamic resistance condition. NOTE In transistor terms, the initial breakdown is in t
28、he BVCBO mode, which changes to the lower voltage BVCEO mode as the breakdown current increases. 3.1.10 overcurrent b-ITU-T K.96: Any current having a peak value exceeding the corresponding peak value of maximum steady-state current at normal operating conditions. 3.1.11 overvoltage b-IEC 60664-2-1:
29、 Any voltage having a peak value exceeding the corresponding peak value of maximum steady-state voltage at normal operating conditions. 3.1.12 power fault b-ITU-T K.96: Abnormal fault condition, when the local AC power service is in electrical contact (power contact) or is magnetically coupled (powe
30、r induction) to another service. 3.1.13 PN junction b-IEC 61836: Junction between a P-type semiconductor and an N-type semiconductor. 3.1.14 punch-through (between two PN junctions) b-IEC 60050-521: Contact between the space charge regions of two PN junctions as a result of widening of one or both o
31、f them. 3.1.15 surge b-ITU-T K.96: Temporary disturbance on the conductors of an electrical service caused by an electrical event not related to the service. NOTE For non-linear SPCs a surge event is defined as an overvoltage or overcurrent or both. 3.1.16 surge protective component (SPC) b-ITU-T K.
32、96: Component specifically included in a device or equipment for the mitigation of the onward propagation of overvoltages or overcurrents or both. 3.1.17 surge protective device (SPD) b-ITU-T K.96: Device that mitigates the onward propagation of overvoltages or overcurrents or both. 3.1.18 Zener bre
33、akdown (of a PN junction) b-IEC 60050-521: Breakdown caused by the transition of electrons from the valence band to the conduction band due to tunnel action under the influence of a strong electric field in a PN junction. 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms Th
34、is Recommendation uses the following abbreviations and acronyms: AC Alternating Current DC Direct Current HDSL High-bit-rate Digital Subscriber Line HFE Hybrid model Forward current gain in common Emitter IC Integrated Circuit ICT Information and Communications Technology IPP Peak Pulse current IPPM
35、 Maximum Peak Pulse current IR Reverse current Rec. ITU-T K.103 (03/2015) 3 MOV Metal-Oxide Varistor NASA National Aeronautics and Space Administration PD Powered Device PHY Physical Layer (usually Ethernet transceiver) PLC Power Line Communication PPPM Maximum Peak Pulse Power PSE Power Sourcing Eq
36、uipment SDSL Symmetrical Digital Subscriber Line SELV Safety Extra Low Voltage SPC Surge Protective Component SPD Surge Protective Device USB Universal Serial Bus V(BR) Breakdown Voltage VC Clamping Voltage VCM Maximum Clamping Voltage VF Forward Voltage V(PT) Punch-Through Voltage VR Reverse Voltag
37、e VRWM Maximum Reverse Working Voltage V(SB) Snapback Voltage 5 Conventions None. 6 Construction 6.1 Packaging There are two types of component packaging used with printed circuit boards: through-hole or surface-mount. Through-hole packaging is typically axial lead or side leaded. Surface-mount pack
38、aging may be leaded or with solderable pads. Figure 1 shows examples of these four package types. 4 Rec. ITU-T K.103 (03/2015) Figure 1 Example component packages (left to right): through-hole, axial and side leaded, surface-mount, leaded and pad 6.2 Semiconductor junction structure and electrical p
39、roperties This clause describes in simple terms the semiconductor chip structure, operation, circuit symbol and basic characteristics. For in depth information on these topics, text books on this subject, such as b-Lindmayer or b-Baliga, should be referenced. 6.2.1 Single PN junction structure and e
40、lectrical characteristic Figure 2 shows a diagram of a simple PN junction structure. Metallization is applied to the top and bottom of the structure for electrical contact. The N-type silicon region has negative carriers (electrons) and the P-type silicon region effectively has positive carriers (ho
41、les). The junction is formed where the material changes from N-type to P-type. A depletion layer is formed at the junction. The depletion region presents a threshold voltage that must be overcome before current can flow. If a voltage is applied with a positive polarity to the P region and negative p
42、olarity to the N region, for voltages above about 0.3 V, current will start to flow. Under these bias conditions the PN junction is termed as being forward biased. Voltages that exceed the threshold voltage will be limited to the forward voltage (VF) characteristic value for the level of available c
43、urrent from the source of the voltage. The Figure 2 graph shows an example of a PN junction forward biased characteristic plotted as forward current, IF, against forward voltage, VF over six decades of current. Above 1 A the voltage starts to increase rapidly as the material starts to run out of inh
44、erent current carriers. The symbol shown next to the structure is for a general purpose rectifier diode. Rec. ITU-T K.103 (03/2015) 5 Figure 2 Forward biased PN junction structure, rectifier diode circuit symbol and electrical forward characteristic Single PN junction voltage limiting can only be us
45、ed where either the signal is a few hundred millivolts or the signal or direct current (DC) supply is in the opposite polarity. The range of applications can be extended by using multiple diodes, either connecting the diodes in series or placing other diodes in the opposite polarity in parallel or b
46、oth; see Figure 3. Four diodes can be used to create a bridge rectifier, useful to make unidirectional breakdown voltage (V(BR) limiters into bidirectional voltage limiters. A commercial example of the eight diode array has a total forward voltage of 2.4 V at 1 mA and 3.9 V at 1 A. Connecting four d
47、iodes in series reduces the array capacitance to 13 pF. The array has a 30 A 10/1000 rating. 6 Rec. ITU-T K.103 (03/2015) Figure 3 Rectifier diode arrays In Figure 4 the battery voltage is reversed compared with Figure 2. A negative polarity voltage is applied to the P region and a positive polarity
48、 voltage to the N region. The battery voltage adds to the natural depletion layer voltage and the depletion layer width expands to support the applied reverse voltage (VR). Under these bias conditions, the PN junction is termed as being reverse biased. The Figure 4 graph shows an example of a PN jun
49、ction reverse biased characteristic plotted as reverse current (IR) against reverse voltage, VR, over seven decades of current. The three characteristics shown are for breakdown diodes with nominal breakdown voltages of 3.6 V, 8.2 V and 15 V. The differences among these characteristics are discussed in clause 7. Voltages that exceed the characteristic voltage will be limited to the VR characteristic value for the level of available current from the source of the voltage. The symbol sh
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