AUGUST 1999 - REVISED FEBRUARY 2005

Specifications are subject to change without notice.

Customers should verify actual device performance in their specific applications.

From 2001, the registrations for FCC equipment changed from the FCC to ACTA, Administrative Council for Terminal Attachments. For this

function, ACTA needed to adopt a US National standard specifying terminal equipment requirements. The TIA, Telecommunications Industry

Association, in conjunction with the EIA, Electronic Industries Alliance, created TIA/EIA-IS-968 for this purpose. The first issue of TIA/EIA-IS-968

is essentially a renumbered version of the FCC Part 68 requirement. Clause and figure changes are shown in the table.

FCC Part 68, ACTA, TIA and EIA

To verify the withstand capability and safety of the equipment, standards require that the equipment is tested with various impulse wave forms.

The table below shows values for the TIA/EIA-IS-968 and ITU-T recommendation K.21.

TISP4xxxL3BJ Overvoltage Protector Series

APPLICATIONS INFORMATION

TIA/EIA-IS-968 (FCC Part 68) Impulse Testing

Item

FCC Part 68

TIA/EIA-IS-968

Telephone Line Surge – Type A

Clause 68.302 (b)

Clause 4.2.2

Telephone Line Surge – Type B

Clause 68.302 (c)

Clause 4.2.3

Simplified Surge Generator

Fig. 68.302 (a)

Figure 4.1

Open Circuit voltage Wave shape

Fig. 68.302 (b)

Figure 4.2

Short Circuit Current Wave shape

Fig. 68.302 (c)

Figure 4.3

Standard

Test

Condition

V

Peak

Voltage

V

Voltage

Wave Form

µs

Peak

Current

A

Current

Wave Form

µs

Fictive

Impedance

Ω

TISP4xxxL3

Rating

A

Series

Resistance

Ω

TIA/EIA-IS-968

(F CC Part 68)

Longitudinal

1500

10/160

200

10/160

7.5

50

2 x 24

Metallic

800

10/560

100

10/560

8

30

19

Longitudinal

1500

9/720 †

37.5

5/320 †

40

40

0

Metallic

1000

9/720 †

25

5/320 †

40

40

0

ITU-T K.21 ‡

Basic Level

Transverse

1500

4000

10/700

37.5

100

5/310

40

30

0

10

ITU-T K.21 ‡

Enhanced Level

Transverse

1500

6000

10/700

37.5

125

5/310

40

30

0

10

† TIA/EIA-IS-968 terminology for the wave forms produced by the ITU-T recommendation K.21 10/700 impulse generator

‡ Values assume the TISP4xxxL3 is connected inter-conductor and a 400 V primary is used

If the impulse generator current exceeds the protector’s current rating then a series resistance can be used to reduce the current to the

protector’s rated value to prevent possible failure. The required value of series resistance for a given wave form is given by the following

calculations. First, the minimum total circuit impedance is found by dividing the impulse generator’s peak voltage by the protector’s rated

current. The impulse generator’s fictive impedance (generator’s peak voltage divided by peak short circuit current) is then subtracted from the

minimum total circuit impedance to give the required value of series resistance.

For the TIA/EIA-IS-968 10/560 wave form the following values result. The minimum total circuit impedance is 800/30 = 26.7 Ω and the

generator’s fictive impedance is 800/100 = 8 Ω. For an inter-conductor connected TISP4xxxL3, this gives a minimum series resistance value of

26.7 - 8 = 18.7 Ω. After allowing for tolerance, a 20 Ω ±5 % resistor would be suitable. The 10/160 wave form only needs to be considered if

the TISP4350L3 is connected from the conductor to ground. In this case, the conductor series resistance is 24 Ω ±5 % per conductor.

These electrical safety standards for IT (Information Technology) equipment at the customer premise use the IEC (International Electro-

technical Commission) 60950 standard as the core document. The IEC 60950 covers fundamental safety criteria such as creepage and

isolation. The connection to a telecommunication network voltage (TNV) is covered in clause 6.

Europe is harmonized by CENELEC (Comité Européen de Normalization Electro-technique) under EN 60950 (included in the Low Voltage

Directive, CE mark). Up to the end of 2000, the US had UL (Underwriters Laboratories) 1950 and Canada CSA (Canadian Standards Authority)

C22.2 No. 950. The US and Canadian standards include regional changes and additions to the IEC 60950. A major addition is the inclusion of

clause 6.6, power cross withstand containing the flowchart Figure 18b and annex NAC covering testing. Remarks made for UL 1950 will

generally be true for CSA 22.2 No. 950.

IEC 60950, UL 1950/60950, CSA C22.2 No. 950/60950 and EN 60950