IEC 61643-321:2001

FOREWORD
1 Scope
2 Normative references
3 Definitions and symbols
4 Basic function and description for ABDs
5 Service conditions
6 Standard test methods and procedures
   6.1 Standard design test criteria
   6.2 Test conditions
   6.3 Clamping voltage V[C] (see figure 2)
   6.4 Rated peak impulse current I[PPM] (see figure 2)
   6.5 Maximum working voltage V[WM] and maximum working
        r.m.s. voltage V[WMrms] (see figure 3)
   6.6 Stand-by current I[D] (see figure 3)
   6.7 Breakdown (avalanche) voltage V[BR] (see figure 4)
   6.8 Capacitance C[j]
   6.9 Rated peak impulse power dissipation P[PPM]
   6.10 Rated forward surge current I[FSM] (see figure 1c)
   6.11 Forward voltage V[FS]
   6.12 Temperature coefficient of breakdown voltage
        (alpha V[BR])
   6.13 Temperature derating (see figure 5)
   6.14 Thermal resistance R[thJA] or R[thJC] or R[thJL]
   6.15 Transient thermal impedance Z[thJA] or Z[thJC] or
        Z[thJL]
   6.16 Rated average power dissipation P[MAV]
   6.17 Peak overshoot voltage V[OS] (see figure 7)
   6.18 Overshoot duration (see figure 7)
   6.19 Response time (see figure 7)
7 Fault and failure modes
   7.1 Degradation fault mode
   7.2 Short-circuit failure mode
   7.3 Open-circuit failure mode
   7.4 'Fail-safe' operation
Figures

Is applicable to avalanche breakdown diodes (ABDs) which represent one type of surge protective device component (hereinafter referred to as SPDC) used in the design and construction of surge protective devices connected to low-voltage power distribution systems, transmission, and signalling networks. Test specifications in this standard are for single ABDs consisting of two terminals. However, multiple ABDs may be assembled within a single package defined as a diode array. Each diode within the array can be tested to this specification. This standard contains a series of test criteria for determining the electrical characteristics of the ABD. From the standard test methods described herein, the performance characteristics and ratings of the ABD can be verified or established for specific packaged designs.