Document
POLYFUSE® Resettable PTCs
Radial Leaded
250R Series
Description • 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. Features • RoHS compliant and lead-free • Fast time-to-trip • Binned and sorted narrow resistance ranges available Applications • Customer Premises Equipment (CPE) • Central Office (CO)/ Telecom Centers
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Agency Approvals
AGENCY AGENCY FILE NUMBER E183209 R50082521
• 0.08 – 0.18 Hold current range, 60VDC operating voltage • 250VAC interrupt rating
• LAN/WAN Equipment • Access equipment
Electrical Characteristics
I hold (A) 0.08 0.08 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.145 0.145 0.145 0.145 0.18 0.18
C: coated device
Part Number
I trip (A) 0.16 0.16 0.24 0.24 0.24 0.24 0.24 0.24 0.24 0.24 0.29 0.29 0.29 0.29 0.65 0.65
Vmax Vint / Vop 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60 250/60
I max (A) 3 3 3 3 3 3 3 3 3 3 3 3 3 3 10 10
Pd max. (W) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1.8 1.8
Maximum Time To Trip Current (A) 0.35 0.35 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Time (Sec.) 3 3 1.5 1.0 0.85 0.7 0.8 0.7 1 1.2 2.5 5 2.5 2.0 21 20 R min (Ω) 15 14 4 7 5.4 6 6 8 8 7 3 3 4.5 5.4 0.8 1.4
Resistance R typ (Ω) 22 22 8 9 7.5 10.5 9 10.5 10 12 6 5.5 6 7.5 2.2 3.9 R 1max (Ω) 33 33 16 16 14 16 16 16 16 16 14 12 14 14 4 4.5
Agency Approvals
250R080T 250R080 250R120 250R120-RA 250R120-RC 250R120-RF 250R120-R1 250R120-R2 250R120-R3 250R120T 250R145 250R145-RA 250R145-RB 250R145T 250R180 250R180T
*typical value
X X X X X X X X X X X X X X X X
X X X X X X X X X X X X X X X X
T: pre-tripped device
250R Series Specifications are subject to change without notice.
Electronics Designers Guide
www.littelfuse.com ©2006 Littelfuse
POLYFUSE® Resettable PTCs
Radial Leaded
Temperature Rerating
Ambient Operation Temperature -40°C Part Number 250R080 250R080T 250R120 250R120T 250R145 250R145T 250R180 250R180T 0.12 0.12 0.18 0.18 0.26 0.26 0.28 0.28
250R Series
-20°C
0°C
23°C
40°C Hold Current (A)
50°C
60°C
70°C
85°C
0.11 0.11 0.16 0.16 0.20 0.20 0.23 0.23
0.09 0.09 0.14 0.14 0.17 0.17 0.21 0.21
0.08 0.08 0.12 0.12 0.145 0.145 0.18 0.18
0.06 0.06 0.10 0.10 0.12 0.12 0.16 0.16
0.05 0.05 0.09 0.09 0.11 0.11 0.13 0.13
0.05 0.05 0.08 0.08 0.09 0.09 0.10 0.10
0.04 0.04 0.06 0.06 0.08 0.08 0.11 0.11
0.03 0.03 0.05 0.05 0.06 0.06 0.083 0.083
Average Time Current Curves
0.120A 0.145A 0.080A 0.180A
Temperature Rerating Curve
170% 150% Percentage of Rated Current 130% 110% 90% 70% 50% 30% 10%
100000
10000
1000
TIME IN SECONDS
100
10
-40 -30 -20
-10
0
10
20 30 40 Temperature (°C)
50
60
70
80
1
0.100
0.010
0.001 0.02 0.100 1 10 100
CURRENT IN AMPERES
Specifications are subject to change without notice.
Note: 1.00 means the number one with two decimal places. AKL V3.9 06.05.18
The average time current curves and temperature rerating curve performance is affected by a number or variables, and these curves provided as guidance only. Customer must verify the performance in their application.
250R Series Specifications are subject to change without notice.
Electronics Designers Guide
www.littelfuse.com ©2006 Littelfuse
POLYFUSE® Resettable PTCs
Radial Leaded
Agency Specification Selection Guide For Telecom and Networking Applications
Product 250R120 250R145 250R180 Lightning ITU K.20/21/45 – 1.5kV 10/700μs ITU K.20/21/45 – 4kV 10/700μs* ITU K.20/21/45 – 1.5kV 10/700μs ITU K.20/21/45 – 4kV 10/700μs* Telcordia GR – 974 – 1.0kV 10/1000μs Power Cross ITU K.20/21/45 – 230Vac, 10Ω ITU K.20/21/45 – 600Vac, 600Ω 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
Protection Application Guide
Region/Specification Application *Access network equipment Remote terminal Repeaters WAN equipment Cross –connect Customer and IT equipment Analog modems ADSL, xDSL Phone sets, PBX systems Internet appliances POS terminals Central Office POTS/ISDN linecards T1/E1/J1 linecards ADSL/VDSL splitters CSU/DSU Device Selection 250R180 250R180T 250R145 250R145T 250R120 250R120T 250R180 250R180T 250R145 250R145T 250R120 250R120T 250R180 250R180T 250R145 250R145T 250R120 250R120T 250R180 250R180T 250R145 250R145T 250R120 250R120T 250R180 250R180T 250R145 250R145T 250R120 250R120T 250R080
South America/Asia/Europe ITU K.45
South America/Asia/Europe ITU K.21
South America/Asia/Europe ITU K.20
North America Telcordia GR-974 South America/Asia/Europe ITU K.20 North America Telcordia GR-1089 South America/Asia/Europe ITU K.20 and K.21
*Primary protection modules MDF modules Network interface
*Intrabuilding communication systems LAN, VOIP cards Local lo.