© 2017 Littelfuse, Inc.

Specifications are subject to change without notice.

Revised: 03/22/17

Radial Leaded > 250R Series

Protection Application Guide

Region/Specification

Application

Device Selection

South America/Asia/Europe

ITU K.45

*Access network equipment

Remote terminal

Repeaters

WAN equipment

Cross –connect

250R180

250R180T

250R145

250R145T

250R120

250R120T

South America/Asia/Europe

ITU K.21

Customer and IT equipment

Analog modems

ADSL, xDSL

Phone sets, PBX systems

Internet appliances

POS terminals

250R180

250R180T

250R145

250R145T

250R120

250R120T

South America/Asia/Europe

ITU K.20

Central Office

POTS/ISDN linecards

T1/E1/J1 linecards

ADSL/VDSL splitters

CSU/DSU

250R180

250R180T

250R145

250R145T

250R120

250R120T

North America Telcordia

GR-974

*Primary protection modules

MDF modules

Network interface

250R180

250R180T

250R145

250R145T

250R120

250R120T

South America/Asia/Europe

ITU K.20

North America Telcordia

GR-1089

*Intrabuilding communication systems

LAN, VOIP cards

Local loop handsets

250R180

250R180T

250R145

250R145T

250R120

250R120T

South America/Asia/Europe

ITU K.20 and K.21

LAN Intrabuilding power cross

Protection

LAN equipment, IP phone

250R080

*Resistance binned parts are recommended

Agency Specification Selection Guide For Telecom and Networking Applications

Product

Lightning

Power Cross

250R120

250R145

ITU K.20/21/45 – 1.5kV 10/700μs

ITU K.20/21/45 – 4kV 10/700μs*

ITU K.20/21/45 – 230Vac, 10Ω

ITU K.20/21/45 – 600Vac, 600Ω

250R180

ITU K.20/21/45 – 1.5kV 10/700μs

ITU K.20/21/45 – 4kV 10/700μs*

Telcordia GR – 974 – 1.0kV 10/1000μs

ITU K.20/21/45 – 230Vac, 10Ω

ITU K.20/21/45 – 600Vac, 600Ω

Telcordia GR – 974- 283Vac, 10A

*Devices should be independently evaluated and tested for use in any specific application