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126 Revision: 21-Feb-08
NFR25/25H
Vishay BCcomponents
Fusible, Non-Flammable Resistors
A homogenous film of metal alloy is deposited on a high
grade ceramic body. After a helical groove has been cut in
the resistive layer, tinned connecting wires of electrolytic
copper are welded to the end-caps. The resistors are coated
with a grey, flame retardant lacquer which provides
electrical, mechanical, and climatic protection. The
encapsulation is resistant to all cleaning solvents in
accordance with “MIL-STD-202E, method 215”, and
“IEC 60068-2-45”.
FEATURES
•Overload protection without risk of fire
•Wide range of overload currents
(refer Fusing Characteristics graphs)
•Lead (Pb)-free solder contacts
•Pure tin plating provides compatibility with lead (Pb)-free
and lead containing soldering processes
•Compatible with “Restriction of the use of Hazardous
Substances” (RoHS) directive 2002/95/EC (issue 2004)
APPLICATIONS
•Audio
•Video
Notes:
(1) Ohmic values (other than resistance range) are available on request
• R value is measured with probe distance of 24 ± 1 mm using 4-terminal method
12NC INFORMATION
•The resistors have a 12-digit numeric code starting with 23
•The subsequent 7 digits indicate the resistor type and
packaging
•The remaining 3 digits indicate the resistance values:
– The first 2 digits indicate the resistance value
– The last digit indicates the resistance decade
Last Digit of 12NC Indicating Resistance Decade
12NC Example
The 12NC for a NFR25 resistor with value 750 Ω, supplied
on a bandolier of 1000 units in ammopack is:
2322 205 13751.
TECHNICAL SPECIFICATIONS
DESCRIPTION VALUE
NFR25 NFR25H
Resistance Range (1) 0.22 Ωto 15 kΩ
Resistance Tolerance and Series ± 5 %; E24 series
Maximum Dissipation at Tamb =70°C0.33W0.5W
Thermal Resistance Rth 240 K/W 150 K/W
Temperature Coefficient:
0.22 Ω≤R≤4.7 Ω≤ ± 200 x 10-6/K ≤ ± 200 x 10-6/K
4.7 Ω<R≤15 Ω≤ ± 200 x 10-6/K ≤ ± 100 x 10-6/K
15 Ω<R≤15 kΩ≤ ± 100 x 10-6/K ≤ ± 100 x 10-6/K
Maximum Permissible Voltage (DC or RMS) 250 V 350 V
Basic Specifications IEC 60115-1 and 60115-2
Climatic Category (IEC 60068) 55/155/56
Stability After:
Load ΔR max.: ± (1 % R + 0.05 Ω)
Climatic Tests ΔR max.: ± (1 % R +0.05Ω)
Soldering ΔR max.: ± (0.25 % R +0.05Ω)
RESISTANCE DECADE LAST DIGIT
0.22 to 0.91 Ω7
1to9.1Ω8
10 to 91 Ω9
100 to 910 Ω1
1to9.1kΩ2
10 to 15 kΩ3
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Revision: 21-Feb-08 127
NFR25/25H
Fusible, Non-Flammable Resistors Vishay BCcomponents
Notes:
(1) Please refer to table PACKAGING for details.
• The PART NUMBER is shown to facilitate the introduction of a unified part numbering system for ordering products.
12NC - resistor type and packaging
TYPE
ORDERING CODE 23.. ... .....
BANDOLIER IN AMMOPACK BANDOLIER
ON REEL
RADIAL TAPED STRAIGHT LEADS STRAIGHT LEADS
4000
UNITS
1000
UNITS
5000
UNITS
5000
UNITS
NFR25 06 204 03... 22 205 13... 22 205 33... 22 205 23...
NFR25H 06 207 03... 22 207 13... 22 207 33... 22 207 23...
PART NUMBER AND PRODUCT DESCRIPTION
PART NUMBER: NFR2500002207JA100
MODEL/SIZE SPECIAL CHARACTER TCR/MATERIAL VALUE TOLERANCE PA CK AG I N G (1) SPECIAL
NFR2500
NFR25H0
0 = Neutral
Z = Value overflow
(Special)
0 = Standard 3 digit value
1 digit multiplier
MULTIPLIER
7 = *10-3
8 = *10-2
9 = *10-1
0 = *100
1 = *101
2 = *102
J = ± 5 % N4
A5
A1
R5
The 2 digits
are used for
all special
parts.
00 = Standard
PRODUCT DESCRIPTION: NFR25 5 % A1 R22
NFR25 5 % A1 R22
MODEL/SIZE TOLERANCE PACKAGING (1) RESISTANCE VALUE
NFR25
NFR25H
± 5 % N4
A5
A1
R5
1K0 = 1 kΩ
4R7 = 4.7 Ω
PACKAGING
CODE PIECES DESCRIPTION MODEL/SIZE
N4 4000 Bandolier in ammopack radial taped
NFR25, NFR25H
A5 5000 Bandolier in ammopack straight leads
A1 1000 Bandolier in ammopack straight leads
R5 5000 Bandolier on reel straight leads
25RFN00002207JA100
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128 Revision: 21-Feb-08
NFR25/25H
Vishay BCcomponents Fusible, Non-Flammable Resistors
DIMENSIONS
MARKING
The nominal resistance and tolerance are marked on the
resistor using four coloured bands in accordance with
IEC publication 60062 “Color codes for fixed resistors”.
For ease of recognition a fifth ring is added, which is violet for
type NFR25 and white for type NFR25H.
OUTLINES
The length of the body (L1) is measured by inserting the
leads into holes of two identical gauge plates and moving
these plates parallel to each other until the resistor body is
clamped without deformation (“IEC publication 60294”).
FUNCTIONAL PERFORMANCE
PRODUCT CHARACTERIZATION
Standard values of nominal resistance are taken from the
E24 series for resistors with a tolerance of ± 5 %.
The values of the E24 series are in accordance with
“IEC publication 60063”.
Note:
(1) The maximum voltage that may be continuously applied to the resistor element, see “IEC publication 60115-1”.
The maximum permissible hot-spot temperature is 155 °C.
Ø D
L
1
L
2
Ø d
Outline
DIMENSIONS - resistor types and relevant physical dimensions
TYPE Ø Dmax. L1 max. L2 max. Ø d
NFR25
2.5 6.5 7.5 0.58 ± 0.05
NFR25H
MASS PER 100 UNITS
TYPE MASS
(g)
NFR25 20.1
NFR25H 20.1
LIMITING VALUES
TYPE LIMITING VOLTAGE (1)
(V)
LIMITING POWER
(W)
NFR25 250 0.33
NFR25H 350 0.5
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Revision: 21-Feb-08 129
NFR25/25H
Fusible, Non-Flammable Resistors Vishay BCcomponents
The power that the resistor can dissipate depends on the operating
temperature.
The resistors will fuse without the risk of fire and within an indicated
range of overload. Fusing means that the resistive value of the
resistor increases at least 100 times.
The fusing characteristic is measured under constant voltage.
Maximum dissipation (Pmax.) in percentage of rated power as a
function of the ambient temperature (Tamb)
Derating
Fusing Characteristics
70 100 50
0
0
50
100
155
- 55
T
a
m
b
( °C)
P
max.
(%
P
rated
)
10
3
10
2
10
1
10
- 1
12
4 0 8
P
overload
(W)
t
(s)
16 20 24
NFR25 This graph is based on measured data which may deviate
according to the application. Fusing Characteristics: ≤ 1 Ω
10
3
10
2
10
1
124 0 8
P
overload (W)
t
(s)
10
- 1
NFR25 This graph is based on measured data
which may deviate according to the application.
Fusing Characteristics: 1 Ω ≤ R ≤ 15 Ω
10
3
10
2
10
1
10
- 1
12
4 0 8
P
overload
(W)
t
(s)
16 20 24
NFR25H This graph is based on measured data
which may deviate according to the application.
Fusing Characteristics: ≤ 1 Ω
10
3
10
2
10
1
12 4 0 8
P
overload (W)
t
(s)
10
- 1
NFR25 This graph is based on measured data
which may deviate according to the application.
Fusing Characteristics: 15 Ω ≤ R ≤ 15 kΩ
10
3
10
2
10
1
12
40 8
P
overload
(W)
t
(s)
16 20 24
10
- 1
NFR25H This graph is based on measured data
which may deviate according to the application.
Fusing Characteristic: 1 Ω ≤ R ≤ 15 kΩ
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130 Revision: 21-Feb-08
NFR25/25H
Vishay BCcomponents Fusible, Non-Flammable Resistors
Pulse Loading Capabilities
103
103
10
1
10- 1
50
20
10
5
2
P
max.
(W)
i (s)
t
pi
/ = 1000
t
t
10- 6 10- 5 10- 4 10- 3 10- 2 10- 1 1
500
200
100
NFR25 Pulse on a regular basis; maximum permissible peak pulse power (Pmax.) as a function
of pulse duration (ti), 0.22 Ω≤R<15Ω
103
102
10
1
10- 1
i (s)
t
P
max.
(W)
pi
/ = 1000
tt
20
2
100
10- 6 10- 5 10- 4 10- 3 10- 2 10- 1 1
NFR25 Pulse on a regular basis; maximum permissible peak pulse power (Pmax.) as a function
of pulse duration (ti), 15 Ω<R≤15 kΩ
600
01
500
400
300
200
100
V
max.
(V)
i (s)
t
10- 6 10- 5 10- 4 10- 3 10- 2 10- 1
NFR25 Pulse on a regular basis; maximum permissible peak pulse voltage Vmax. as a function
of pulse duration (ti)
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Revision: 21-Feb-08 131
NFR25/25H
Fusible, Non-Flammable Resistors Vishay BCcomponents
Pulse Loading Capabilities
Application Information
103
102
10
12
5
10
20
50
100
200
500
pi
/ = 1000
tt
i (s)
t
P
max.
(W)
10- 1
10- 6 10- 5 10- 4 10- 3 10- 2 10- 1 1
NFR25H Pulse on a regular basis; maximum permissible peak pulse power (Pmax.) as a function
of pulse duration (ti)
1200
0
400
10- 6 10- 5 10- 4 10- 3 10- 2 10- 1 1
800
V
max.
(V)
t
i (s)
NFR25H Pulse on a regular basis; maximum permissible peak pulse voltage (Vmax.) as a function
of pulse duration (ti)
100
0 0.2 0.6
0
0.4
20
40
60
80
P
(W)
∆
T
(K)
NFR25 Hot-spot temperature rise (ΔT)
as a function of dissipated power
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132 Revision: 21-Feb-08
NFR25/25H
Vishay BCcomponents Fusible, Non-Flammable Resistors
TESTS AND REQUIREMENTS
Essentially all tests are carried out in accordance with the
schedule of “IEC publication 60115-1”, category
LCT/UCT/56 (rated temperature range: Lower Category
Temperature, Upper Category Temperature; damp heat,
long term, 56 days). The testing also covers the
requirements specified by EIA and EIAJ.
The tests are carried out in accordance with IEC publication
60068-2, “Recommended basic climatic and mechanical
robustness testing procedure for electronic components” and
under standard atmospheric conditions according to
“IEC 60068-1”, subclause 5.3.
In the Test Procedures and Requirements table the tests and
requirements are listed with reference to the relevant clauses
of “IEC publications 60115-1 and 60068-2”; a short
description of the test procedure is also given. In some
instances deviations from the IEC recommendations were
necessary for our method of specifying. For inflammability
requirements reference is made to “IEC 60115-1” and to
“EN 140000, appendix D”.
All soldering tests are performed with mildly activated flux.
Minimum distance from resistor body to PCB = 1 mm
NFR25 Temperature rise (ΔT) at the lead end (soldering point)
as a function of dissipated power at various lead lengths after
mounting
NFR25H Hot-spot temperature rise (ΔT) as a
function of dissipated power.
Minimum distance from resistor body to PCB = 1 mm
NFR25H Temperature rise (ΔT) at the lead end (soldering point) as a
function of dissipated power at various lead lengths after mounting
Application Information
50
0 0.2 0.6
00.4
10
20
30
40
P
(W)
∆
T
(K)
15 mm
5 mm
10 mm
100
0 0.2 0.6
00.4
20
40
60
80
P
(W)
∆
T
(K)
50
0 0.2 0.6
0
0.4
10
20
30
40
P
(W)
∆
T
(K)
15 mm
5 mm
10 mm
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Revision: 21-Feb-08 133
NFR25/25H
Fusible, Non-Flammable Resistors Vishay BCcomponents
TEST PROCEDURES AND REQUIREMENTS
IEC
60115-1
CLAUSE
IEC
60068-2
TEST
METHOD
TEST PROCEDURE
REQUIREMENTS
NFR25 NFR25H
TESTS IN ACCORDANCE WITH THE SCHEDULE OF IEC PUBLICATION 60115-8
4.4.1 visual examination no holes; clean surface; no damage
4.4.2 dimensions (outline) gauge (mm) see Dimensions Table
4.5
resistance
(refer note on first page for
measuring distance)
applied voltage (+ 0/- 10 %):
R-Rnom: max. ± 5 %
R< 10 Ω: 0.1 V
10 Ω≤R< 100 Ω:0.3V
100 Ω≤R<1kΩ:1V
1kΩ≤R<10kΩ:3V
10 kΩ≤R≤15 kΩ:10V
4.18 20 (Tb) resistance to soldering
heat
thermal shock: 3 s; 350 °C;
3 mm from body ΔR max.: ± (0.25 % R + 0.05 Ω)
4.29 45 (Xa) component solvent
resistance
isopropyl alcohol or H2O followed by
brushing in accordance with
“MIL 202 F
”
no visual damage
4.17 20 (Ta) solderability 2 s; 235 °C good tinning; no damage
4.7 voltage proof on insulation URMS = 500 VRMS during
1 min; metal block method no breakdown or flashover
4.16 21 (U) robustness of terminations:
4.16.2 21 (Ua1) tensile all samples load 10 N; 10 s number of failures < 10 x 10−6
4.16.3 21 (Ub) bending half number of
samples load 5 N; 4 x 90°number of failures < 10 x 10−6
4.16.4 21 (Uc) torsion other half of
samples 3 x 360° in opposite directions no damage
ΔR max.: ± (0.25 % R + 0.05 Ω)
4.20 29 (Eb) bump 3 x 1500 bumps in 3 directions; 40 g no damage
ΔR max.: ± (0.25 % R + 0.05 Ω)
4.22
6 (Fc) vibration
frequency 10 Hz to 500 Hz;
displacement 1.5 mm or acceleration
10 g; 3 directions; total 6 h
(3 x 2 h)
no damage
ΔR max.: ± (0.25 % R+ 0.05 Ω)
4.19 14 (Na) rapid change of
temperature
30 min at LCT and
30 min at UCT; 5 cycles
no visual damage
ΔR max.: ± (0.25 % + 0.05 Ω)
4.23 climatic sequence:
4.23.3 30 (Db) damp heat (accelerated)
1st cycle
4.23.6 30 (Db) damp heat (accelerated)
remaining cycles 6 days; 55 °C; 95 % to 98 % RH Rins min.: 103MW
ΔR max.: ± (1 % R + 0.05 Ω)
4.24.2
3 (Ca) damp heat
(steady state) (IEC)
56 days; 40 °C;90 %to95 %RH;
loaded with 0.01 Pn
(IEC steps: 4 to 100 V)
Rins max.: 1000 MΩ
ΔR max.: ± (1 % R + 0.05 Ω)
4.25.1
endurance (at 70 °C)
1000 h;
loaded with Pn or Vmax.;
1.5 h ON and 0.5 h OFF
ΔR max.: ± (1 % R + 0.05 Ω)
4.25.3 endurance at upper
category temperature
1000 h;
no load ΔR max.: ± (1 % R + 0.05 Ω)
4.8.4.2
temperature coefficient
at 20/LCT/20 °C and
20/UCT/20 °C (TCR x 10−6/K):
0.22 Ω≤R≤4.7 Ω≤ ± 200 x 10-6/K ≤ ± 200 x 10-6/K
4.7 Ω<R≤15 Ω≤ ± 200 x 10-6/K ≤ ± 100 x 10-6/K
15 Ω<R≤15 kΩ≤ ± 100 x 10-6/K ≤ ± 100 x 10-6/K
4.12 noise “IEC publication 60195” < 0.1 µV/V
4.26 accidental overload cheese-cloth nonflammable
OTHER TESTS IN ACCORDANCE WITH IEC 60115 CLAUSES AND IEC 60068 TEST METHOD
4.17
20 (Ta) solderability
(after ageing)
8 h steam or 16 h 155 °C;
leads immersed 6 mm
for 2± 0.5s
in a solder bath at 235 ± 5 °C
good tinning (≥ 95 % covered);
no damage
4.6.1.1 insulation resistance maximum voltage Umax. DC = 500 V
after 1 min; metal block method Rins min.: 104MΩ
see 2nd amendment
to “IEC 60115-1”, Jan.’87 pulse load see the Pulse Loading Capabilities
graphs
Document Number: 91000 www.vishay.com
Revision: 18-Jul-08 1
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Legal Disclaimer Notice
Vishay
All product specifications and data are subject to change without notice.
Vishay Intertechnology, Inc., its affiliates, agents, and employees, and all persons acting on its or their behalf
(collectively, “Vishay”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained herein
or in any other disclosure relating to any product.
Vishay disclaims any and all liability arising out of the use or application of any product described herein or of any
information provided herein to the maximum extent permitted by law. The product specifications do not expand or
otherwise modify Vishay’s terms and conditions of purchase, including but not limited to the warranty expressed
therein, which apply to these products.
No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this
document or by any conduct of Vishay.
The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications unless
otherwise expressly indicated. Customers using or selling Vishay products not expressly indicated for use in such
applications do so entirely at their own risk and agree to fully indemnify Vishay for any damages arising or resulting
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