www.littelfuse.com

©2006 Littelfuse

250R Series

Specifications are subject to change without notice.



Electronics Designers Guide

Radial Leaded

• The 250R series is designed to protect against short

duration high voltage fault currents (power cross or

power induction surge) typically found in telecom

applications (250Vrms). The series can be used to help

telecom networking equipment meet the protection

requirements specified in ITU K.20 and K.21.

Electrical Characteristics

Part Number

I

hold

(A)

I

trip

(A)

V

max

V

I

max

(A)

P

d

max.

(W)

Maximum Time

To Trip

Resistance

Agency

Approvals

Current

(A)

Time

(Sec.)

R

min

(

Ω)

R

typ

(

Ω)

R

1max

(

Ω)

250R080T

0.08

0.16

250/60

3

1

0.35

3

15

22

33

X

X

250R080

0.08

0.16

250/60

3

1

0.35

3

14

22

33

X

X

250R120

0.12

0.24

250/60

3

1

1

1.5

4

8

16

X

X

250R120-RA

0.12

0.24

250/60

3

1

1

1.0

7

9

16

X

X

250R120-RC

0.12

0.24

250/60

3

1

1

0.85

5.4

7.5

14

X

X

250R120-RF

0.12

0.24

250/60

3

1

1

0.7

6

10.5

16

X

X

250R120-R1

0.12

0.24

250/60

3

1

1

0.8

6

9

16

X

X

250R120-R2

0.12

0.24

250/60

3

1

1

0.7

8

10.5

16

X

X

250R120-R3

0.12

0.24

250/60

3

1

1

1

8

10

16

X

X

250R120T

0.12

0.24

250/60

3

1

1

1.2

7

12

16

X

X

250R145

0.145

0.29

250/60

3

1

1

2.5

3

6

14

X

X

250R145-RA

0.145

0.29

250/60

3

1

1

5

3

5.5

12

X

X

250R145-RB

0.145

0.29

250/60

3

1

1

2.5

4.5

6

14

X

X

250R145T

0.145

0.29

250/60

3

1

1

2.0

5.4

7.5

14

X

X

250R180

0.18

0.65

250/60

10

1.8

1

21

0.8

2.2

4

X

X

250R180T

0.18

0.65

250/60

10

1.8

1

20

1.4

3.9

4.5

X

X

*typical value

C: coated device

T: pre-tripped device

Description

Features

Applications

• RoHS compliant and

lead-free

• Fast time-to-trip

• Binned and sorted narrow

resistance ranges available

• 0.08 – 0.18 Hold current

range, 60VDC operating

voltage

• 250VAC interrupt rating

• Customer Premises

Equipment (CPE)

• Central Office (CO)/

Telecom Centers

• LAN/WAN Equipment

• Access equipment

250R Series

Agency Approvals

AGENCY

AGENCY FILE NUMBER

E183209

R50082521