MARCH 1994 - REVISED SEPTEMBER 2008

Specifications are subject to change without notice.

Customers should verify actual device performance in their specific applications.

The electrical characteristics of a TISP® device are strongly dependent on junction temperature, TJ. Hence, a characteristic value will depend

on the junction temperature at the instant of measurement. The values given in this data sheet were measured on commercial testers, which

generally minimize the temperature rise caused by testing. Application values may be calculated from the parameters’ temperature coefficient,

the power dissipated and the thermal response curve, Zθ (see M. J. Maytum, “Transient Suppressor Dynamic Parameters.” TI Technical

Journal, vol. 6, No. 4, pp.63-70, July-August 1989).

Electrical Characteristics

Lightning Surge

Wave Shape Notation

Generators

Current Rating

APPLICATIONS INFORMATION

TISP30xxF3 (LV) Overvoltage Protector Series

Most lightning tests, used for equipment verification, specify a unidirectional sawtooth waveform which has an exponential rise and an

exponential decay. Wave shapes are classified in terms of peak amplitude (voltage or current), rise time and a decay time to 50 % of the

maximum amplitude. The notation used for the wave shape is

amplitude, rise time/decay time. A 50 A, 5/310 µs wave shape would have a

peak current value of 50 A, a rise time of 5 µs and a decay time of 310 µs. The TISP® device surge current graph comprehends the wave

shapes of commonly used surges.

There are three categories of surge generator type, single wave shape, combination wave shape and circuit defined. Single wave shape

generators have essentially the same wave shape for the open circuit voltage and short circuit current (e.g., 10/1000 µs open circuit voltage

and short circuit current). Combination generators have two wave shapes, one for the open circuit voltage and the other for the short circuit

current (e.g., 1.2/50 µs open circuit voltage and 8/20 µs short circuit current). Circuit specified generators usually equate to a combination

generator, although typically only the open circuit voltage waveshape is referenced (e.g. a 10/700 µs open circuit voltage generator typically

produces a 5/310 µs short circuit current). If the combination or circuit defined generators operate into a finite resistance, the wave shape

produced is intermediate between the open circuit and short circuit values.

When the TISP® deviceswitches into the on-state, it has a very low impedance. As a result, although the surge wave shape may be defined in

terms of open circuit voltage, it is the current wave shape that must be used to assess the required TISP® surge capability. As an example, the

ITU-T K.21 1.5 kV, 10/700 µs open circuit voltage surge is changed to a 38 A, 5/310 µs current waveshape when driving into a short circuit.

Thus, the TISP® surge current capability, when directly connected to the generator, will be found for the ITU-T K.21 waveform at 310 µs on the

surge graph and not 700 µs. Some common short circuit equivalents are tabulated below:

Standard

Open Circuit Voltage Short Circuit Current

ITU-T K.21

1.5 kV, 10/700 µs

37.5 A, 5/310 µs

ITU-T K.20

1 kV, 10/700 µs

25 A, 5/310 µs

IEC 61000-4-5, combination wave generator

1.0 kV, 1.2/50 µs

500 A, 8/20 µs

Telcordia GR-1089-CORE

1.0 kV, 10/1000 µs

100 A, 10/1000 µs

Telcordia GR-1089-CORE

2.5 kV, 2/10 µs

500 A, 2/10 µs

FCC Part 68, Type A

1.5 kV, <10/>160 µs

200 A,<10/>160 µs

FCC Part 68,Type A

800 V, <10/>560 µs

100 A,<10/>160 µs

FCC Part 68, Type B

1.5 kV, 9/720 µs

37.5 A, 5/320 µs

Any series resistance in the protected equipment will reduce the peak circuit current to less than the generators’ short circuit value. A 1 kV

open circuit voltage, 100 A short circuit current generator has an effective output impedance of 10 Ω (1000/100). If the equipment has a series

resistance of 25 Ω, then the surge current requirement of the TISP® device becomes 29 A (1000/35) and not 100 A.