IEEE Std C62.42.3 pdf free download

IEEE Std C62.42.3 pdf free download.Application of Surge Protective Components in Surge Protective Devices and Equi pment Ports-Part 3: Silicon PN-Junction.
4.2 Semiconductor junction structure and electrical properties This subclause describes in simple terms the semiconductor chip structure, operation, circuit symbol and basic characteristics. For in depth information on these topics, text books in this subject, such as Lindmayer and Wrigley [B11] or Baliga [B1], should be referenced. 4.2.1 Single PN-junction structure and electrical 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 (holes). 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 polarity 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 Vp characteristic value for the level of available current from the source of the voltage. The Figure 2 graph shows an example of a PN-junction forward biased characteristic plotted as forward curent, Ip, against forward voltage, V; over six decades of current. Above l A the voltage starts to increase rapidly as the material starts to run out of inherent current carriers. The symbol shown next to the structure is for a general purpose rectifier diode.
Single PN-junction voltage limiting can only be used where either the signal is a few hundred millivolts or the signal or de 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 both, see Figure 3. Four diodes can be used to create a bridge rectifier, useful to make unidirectional breakdown voltage limiters into bidirectional voltage limiters. A commercial example of the eight diode array has a total forward voltage of2.4 V at 1 mA and 3.9 V at 1 A. Connecting four diodes in series reduces the array capacitance to 13 pF. This array has a 30 A 10/1000 rating.
The symbol shown next to the structure is for a PN-junction component designed to be used in the reverse breakdown region. The small hook at the end of the diode symbol bar indicates a reverse breakdown characteristic. This structure has a breakdown characteristic in one voltage polarity and forward diode characteristic in the opposite voltage polarity. These voltage limiting unidirectional diodes are available with breakdown voltages in the range of5 V to 500 V and peak power ratings of 400 W to 5 kW. In restricted voltage ranges, higher power components of 30 kW are available. Lower capacitance components can be produced by incorporating series and shunt rectifier diodes, see Figure 5. The unidirectional array is formed with series and shunt rectifiers. The bidirectional array uses two arms each with a breakdown diode and rectifier. The bridged array uses four rectifier diodes in bridge connection and a breakdown diode. Further bridges can be added. For example, 4 bridges can be used to protect eight digital IC signal connections. The bridged array has direct connections to the breakdown diode so that it can also protect a dc supply.
IEEE Std C62.42.3 pdf download.