4.5
1.3
8.8
Ø 0.8
10.1
13.7
12.5
5.08
15
Ø 3.6
2.5
4.5
1.3
8.8
10.1
12.5
5.08
15
Ø 3.6
0,3
1.8 32
Two versions of this thick film resistors are available :
– a radial lead version for PCB mounting,
– a flat lead version for surface mounting.
The well know TO 220 package is tight and easy to mount.
The main features of this product are :
●A HIGH DENSITY OF POWER DISSIPATION (THE RATIO POWER
DISSIPATION VOLUME IS HIGH)
●A LARGE RANGE OF OHMIC VALUE
●A NEGLIGEABLE INDUCTANCE
●AN EASY MOUNTING
20 W at 25°C
mounted heatsink
MECHANICAL
MECHANICAL PROTECTION... insulated case
RESISTIVE ELEMENT... thick film
END CONNECTIONS... tinned copper
WEIGHT... 2 g max.
DIMENSIONAL
PACKAGE...
standard... TO 220
on request... D2 pack
DD pack
please consult Sfernice
ENVIRONMENTAL
TEMPERATURE RANGE... –55°C +155°C
CLIMATIC CATEGORY... 55 / 155 / 56
SEALED... sealed container
solder immersion
ELECTRICAL
RESISTOR RANGE... 0,046 Ωto 1 MΩ
TOLERANCES standard... ±1% ... ±10%
DISSIPATION AND ASSOCIATED... onto a heatsink
THERMAL RESISTANCE... 20 W at +25°C
Rth (j-c) : 6,5°C/W
free air :
2 W at +25°C
TEMPERATURE COEFFICIENT... see table 1
standard...
±150 ppm/°C
on request...
±50 ppm/°C
LIMITING ELEMENT VOLTAGE... 250 V
DIELECTRIC STRENGTH... 2000 V* RMS
INSULATION RESISTANCE... ≥106MΩ
INDUCTANCE... ≤0,1 µH
CRITICAL RESISTANCE... 3,12 kΩ
* (between leads and case)
Dimensions in mm
Tolerance unless otherwise specified : ± 0,4 mm.
Fig. 2Fig. 1
RTO 20F RTO 20C
SPECIFICATIONS
power resistor
– thick film technology
RTO20
Data sheet E 4/1.718 - 09198
45iV
SERIE
RTO
STYLE
20
CONNECTIONS
F
F : radial leads
C : surface mounting
OHMIC VALUE
100 kΩ
TOLERANCE
±10%
± 1 %
± 2 %
± 5 %
±10 %
SPECIAL DESIGN
xxx
Optional
on request :
special TCR
shape, etc.
ORDERING PROCEDURE
PERFORMANCES
Table 1
TESTS
SHORT TIME OVERLOAD
LOAD LIFE
CLIMATIC SEQUENCE
HUMIDITY (steady state)
HIGH TEMPERATURE EXPOSURE
2 Pr / 5 s
Us < 1,5 UL
56 days H.R. 95%
1000 h - 40% Pr at +100°C
1000 hours Pr at + 25°C
5 cycles
Nominal power Pn – 55°C +155°C
≤± (0,25 % ± 0,05 Ω)
≤± (0,5 % ± 0,05 Ω)
≤± (1 % ± 0,05 Ω)
≤± (0,5 % ± 0,05 Ω)
≤± (0,5 % ± 0,05 Ω)
CONDITIONS TYPICAL DRIFTS
MARKING
Series, style, ohmic value (in Ω), tolerance (in %), manu-
facturing date, SFERNICE trademark.
CONDITIONING
Tube of 50 units.
Table 2
Fig. 4
PARTICULAR FEATURES
ENERGY CURVE
≥0,046 Ω
±300ppm/°C ±250ppm/°C ±150ppm/°C
for R ≥0,1 Ω±50 ppm/°C
±1% at ±10%
≥0,5 Ω≥ 0,1 Ω
Ohmic values
Temperature
coefficient
standard
on request
Tolerances
10
1
0,1
0,01
Fig. 3
AMBIENT TEMPERATURE IN DEGREES CELSIUS
% RATED POWER
100
75
50
25
00 20 25 40 60 80 100 120 140 155
10-6 10-5 10-4 10-3 10-2
POWER RATING CHART
The temperature of the heater should maintained in the
limit specified.
To improve the thermal conductivity, surfaces in contact
should be laid on with a silicone grease and the torque
applied on the screw for tightening should be around
1 Nn.
In any case the applied voltage must be lower than the
maximum overload voltage of 375 V.
Power versus ambient temperature derating factor :
From 25°C (ambient temperature) for a temperature in-
crease of 1,55° the overload power must be reduced by
1%. The corresponding derating factor is obtained by the
formule : θ ambient –25°C
R= 1 –
155°C
Non repetitive overload ≤1s
The acceptable power is obtained by the formula :
E (J)
Pa = x R
T (s)
E : being the energy (fig. 4)
T : duration of overload
R: power derating factor
i.e.: duration of overload 10 ms
ambient temperature 45°
energy : 2 J (fig. 4).
45 –25
R= 1 – = 0,87
155
E 2
Pa = x R= x 0,87 = 174 W
T 0,01
OVERLOADS
Impulsional train of overload :
Taking into account the average power the power accep-
table is : Pn
Pa = x R
K
with Pn : nominal power
K : ratio between the duration of overload impulse
and the period between 2 pulses
R: being the power reduction factor.
OVERLOAD DURATION IN SECOND
ENERGY IN JOULE
VISHAY S.A.
International Department
199, Boulevard de la Madeleine
B.P. 1159
F 06003 NICE CEDEX 1
Tél. : (33) 04 93 37 27 27
Fax : (33) 04 93 37 27 26
45iV
