Document Number: 30256 For technical questions, contact: filmresistors.leaded@vishay.com
www.vishay.com
Revision: 06-Dec-07 5
NFR01, NFR02, NFR03
Fusible Power Metal Film Leaded
Resistors
Vishay BCcomponents
NFR03
FUSING CHARACTERISTIC
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.
TESTS AND REQUIREMENTS
Essentially all tests are carried out in accordance with the schedule of IEC 60115-1, category 55/155/56 (rated temperature range
- 55 to + 155 °C; damp heat, long term, 56 days) and along the lines of IEC 60068-2; “Recommended basic climatic and
mechanical robustness testing procedure for electronic components” and under standard atmosphere conditions according to
IEC 60068-1 subclause 5.3, unless otherwise specified. In some instances deviations from IEC applications were necessary for
our specified method.
Hot Spot Solder Spot
Hot spot temperature rise (ΔT) as a function
of dissipated power
Temperature rise (ΔT) at the lead end (soldering
point) as a function of dissipated power at various leads
lengths after mounting
Resistance Range Power Overload Fusing Time
0.47 Ω - 10 Ω≥ 20 x maximum dissipation at 70 °C (Pn)
≤ 60 s
10.1 Ω - 1 kΩ≥ 16 x maximum dissipation at 70 °C (Pn)
0
20
40
60
80
0100
120
140
160
180
0 0.5 1.0 1.5 2.0 2.5 3.0
(W)
Δ
(°C)
T
Ø 0.80 mm Cu
P
0
20
40
60
80
100
0 0.5 1.0 1.5 2.0
Δ
(°C)
T
Ø 0.80 mm Cu
2.5 3.0
25 mm
15 mm
20 mm
(W)
P
PERFORMANCE
IEC
60115-1
CLAUSE
IEC
60068-2
TEST
METHOD
TEST PROCEDURE
REQUIREMENTS
PERMISSIBLE CHANGE (ΔR)
NFR01 NFR02 NFR03
4.8 -
Temperature
coefficient
Between
- 55 °C and + 155 °C
± 200 ppm/K
4.25.1 - Endurance at 70 °C
1000 h;
loaded with Pn or V
max.
;
1.5 h ON; 0.5 h OFF
± (5 % R + 0.1 Ω)
4.26 - Accidental overload
Overload of 5, 10, 16, 25, 40, 63
and 100 times the rated power,
but the applied voltage shall not
exceed four times the limiting
voltage.
Non-flammable
