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1W 3720W LOW RESISTANCE CHIP RESISTOR
1. Scope
This specification applies to 3.75mm x 2.0mm size 1W, fixed metal film chip
resistors rectangular type for use in electronic equipment.
2. Type Designation
RL3720W
-
-
(1)
(2)
(3)
(4)
Where (1) Series No.
(2) Temperature coefficient of resistanceT.C.R.
(3) Resistance value: refer to paragraph 4-1
For example--
Three digits of number ( R0.1
Ω)
R10 = 0.1
Ω
Four digits of numberR< 0.1
Ω
R022 = 0.022
Ω
The “R” shall be used as a decimal point.
(4) Resistance tolerance: refer to paragraph 4-1.
3. Construction and Physical Dimensions
W
a
a
Code
Letter
L
W
t
a
b
Dimensions(mm)
3720
3.75
0.3
2.00
0.2
0.45 + 0.15/-0.1
0.40
0.2
0.40
0.2
L
b
t
Resistive element : Ni film
(under protection film)
Electrode : Solder (Sn : Pb = 9 :1)
Protection film : Epoxy resin
Substrate : Alumina
Figure 1. Construction and Dimensions
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4. Ratings
4-1 Specification
Power Rating*
1W
Resistance Value
0.01
Ω1.0 Ω
1%(F) ,
2%(G) ,
5%(J)
Resistance Tolerance
Note*:
Power Rating is based on continuous full load operation at rated ambient
temperature of 70°C. For resistors operated at ambient temperature in
excess of 70°C, the maximum load shall be derated in accordance with the
following curve.
%
Rated
dissipation
ratio
100
50
0
-55
70
125
°C
Ambient temperature
Figure 2 Derating Curve
4-2 Rated Voltage
The rated voltage shall be determined by the following expression.
=
×
Where VRated voltage (V)
RNominal resistance value (Ω)
PRated dissipation (W)
4-3 Operating and Storage Temperature Range
-55 to +125°C
5. Marking
Resistance value mark on a top surface use four or three digits by JIS.
White bars are Cyntec internal use only.
Example
0.47
0.022
R022
R47
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6. Characteristics
6-1 Electrical
6-1-1 Resistance
Resistance value shall be within the tolerance specified
in paragraph 4-1
Refer to JIS C 5202 5.1
6-1-2 Temperature Coefficient of Resistance
Not exceed the temperature coefficient of resistance specified in
paragraph 4-1
Room temperature
→
Room temperature +100
Refer to JIS C 5202 5.2
6-1-3 Insulation Resistance
(1) Between Electrode and Protection Film
100MΩ or over
(2) Between Electrode and Substrate
1,000MΩ or over
The resistor shall be cramped in the metal block and tested , as shown
below.
Test voltage : 100V
DC
for 1 minute
Refer to JIS C 5202 5.6 Mounting condition G.
Insulation Prate
Pressure Rod
(Metal)
Measurement Point A
Substrate
Protection Film
Spring
R0.5
Test Sample
Metal Block
Measurement Point B
6-1-4 Voltage Proof
Resistance change :
(0.5%)
Without damage by flashover, fire or breakdown, as shown below.
The resistor shall be tested as shown in paragraph 6-1-3
The voltage : 100V
AC
(rms.) for 1 minute
Refer to JIS C 5202 5.7
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6-2 Mechanical
6-2-1 Terminal Strength
Resistance Change :
(0.5%)
Without mechanical damage such as breaks.
Electrical characteristics shall be satisfied.
Bending Amplitude : 3 mm 30 seconds
Refer to JIS C 5202 6.1.4.
Pressure
20
Press Jig
R230
50
Amplitude
3 mm
Test PC Board
Sample
Refer to EIAJ RC-2530
Solder
Supports
Within
2mm
45
45
Unit : mm
6-2-2 Body Strength
Resistance Change :
(0.5%)
Without mechanical damage such as breaks.
A load of 10N using a R0.5 pressure rod shall be applied to the center
in the direction of the arrow and held for 10 seconds.
Refer to JIS C 5202 6.2
Pressure rod
R0.5
Resistor
1/2L
L
Unit : mm
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6-2-3 Solderability
A new uniform coating of solder shall cover minimum of 95% of the
surface being immersed.
Temperature of solder : 235
±
5
°C
Immersion duration : 2
±
0.5 seconds
Refer to JIS C 5202 6.5
6-2-4 Resistance to Soldering Heat
Resistance change :
±
(0.5%)
Electrical characteristics shall be satisfied.
Without distinct deformation in appearance.
(1) Solder bath method
Pre-heat : 100 to 110 30 seconds
Temperature : 260
5 10
1seconds
(2) Reflow Soldering method
Peak temperature : 240
5 Under 5 seconds
Temperature : 220
5 40 seconds
The heating apparatus shall be the upper-heated oven and
temperature shall be the board surface temperature.
(3) Soldering iron method
Bit temperature : 350
5 Under 5 seconds
The resistor shall be stored at standard atmospheric conditions
for 1 hour, after which the measurements shall be made.
Refer to JIS C 5202 6.4
6-2-5 Resistance to Solvent
Without mechanical damage and distinct damage in appearance.
Immersion cleaning
At normal temperature 300 seconds in Isopropyl Alcohol.
Refer to JIS C 5202 6.9
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