ULTRA MINI SIZE METAL OXIDE FILM RESISTORS
1. Applicable Scope:
This standard specification is for use in consumer electronics, computers,
telecommunications, control instruments...etc.
2. Part Number:
It is composed by Type, Rated Wattage, Nominal Resistance, Tolerance and
Package/Terminal Form
. e.g.
RSU
Type
1W
Rated Wattage
1KΩ
Nominal Resistance
J
Tolerance
T/B
Package/Terminal Form
2.1 Type :
Ultra Mini Size Metal Oxide Film Resistors are called "RSU".
2.2 Rated Wattage:
Shown by "W", such as 1W, 2W, 3W.
2.3 Nominal Resistance:
Ω,
KΩ, MΩare its unit, which be in accordance with JIS-C6409 article 6 (EIA
RS-196A) series.
2.4 Tolerance:
It is measured by Bridge-method at room temperature and expressed by a capital
letter.
G＝±2%, J＝±5%.
2.5 Package/Terminal Form:
T/R＝tape & reel; T/B＝tape in box; Nil＝Bulk; MG form; F forms.
Remark : RSU Series Resistors are RoHS Compliant.
3. Rated Power:
Rated power is the value of Max load voltage specified at the ambient temperature of
70℃, and shall meet the functions of electrical and mechanical performance. When
the ambient temperature surpasses above mentioned temperature, the value declines
as per following DERATING CURVE.
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ULTRA MINI SIZE METAL OXIDE FILM RESISTORS
3.1 Rated Voltage:
It is calculated through the following formula:
E
=
P
*
R
where
E: rated voltage (V)
P: rated power (W)
R: nominal resistance value (Ω)
However, in case the voltage calculated exceeds the maximum load voltage, such
the maximum load voltage shall be regarded as its rated voltage, means
whichever less.
4. Dimension and structure:
4.1 Dimension:
Unit: mm
TYPE
L±1
RSU
1W
2W
3W
6.8
9
15
2.6 ± 0.5
3.5
5
28
28
28
0.6
0.8
0.8
0.22Ω~1MΩ
0.22Ω~1MΩ
0.22Ω~1MΩ
D±1
H±3
d ± 0.1
Resistance Range
Max Working
Voltage
350V
500V
750V
4.2 Structure:
4.2.1 Ceramic Rod:
It is made of Forsterite imported from Japan.
4.2.2 Terminal:
Terminal is to be firmly connected with resistors element, both electrically
and mechanically, and allow easy soldering.
4.2.3 Coating:
Coating is done by dark red flameproof paint (resistant to 800℃) which is
solid enough to be free from looseness, crack and easy breakage. It is also
resistant to cleaning and industrial solvents, and the paint shall be limited
within 2mm of lead wires from resistor body.
4.2.4 Marking:
Marking is made on resistors surface, by four color coding.
1st, 2nd, 3rd: nominal resistance
4th: tolerance
5. Operating Temperature Range: -55℃½155℃
6. Mechanical Performance:
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ULTRA MINI SIZE METAL OXIDE FILM RESISTORS
6.1 Terminal tensile:
To fix the resistor body, a static load of 2.5kgs. (under 1W:1kg.)is to be gradually
applied into the terminal for 10 seconds without causing any looseness and fall.
6.2 Twist withstand:
To bend the lead wire at the point of about 6mm from resistor body to 90°, then
catch the wire at 1.2
±0.4mm
apart from the bent point end and turn it (clockwise)
by 360 degrees perpendicular to the resistor axis at speed of 5 seconds per turn,
and do the same counterclockwise again which constitute a whole turn. Repeat
the turn 2 times without causing any break and looseness.
7. Electrical Performance:
7.1 Resistance Temperature Coefficient:
It shall be within
±300ppm/℃.
T.C (ppm/℃) =［(R2－R1)÷R1½×［1÷(T2－T1)½×10
6
R1: resistance value at reference temperature
R2: resistance value at test temp.
T1: reference temp. (usu. 25℃)
T2: test temp. (about 75℃)
7.2 Temperature Cycle:
Following temp. cycles are to be made 5 times and then put at room temp. for one
hour, the resistance value change rate between pre-and-post test shall be within
±1%
Steps
1
st
step
2
nd
step
3
rd
step
4
th
step
Temperature(℃)
-55 ± 3
Room temp.
155 ± 3
Room temp.
Time (minutes)
30
3
30
3
where
7.3 Insulation Character :
Resistors are located in a V-shaped metal trough. Using the DC 500V megger
instrument 2 poles to clutch either side of lead wires and metal trough, measuring
the Insulation Resistance which shall be over 1000MΩ.
7.4 Voltage Withstanding:
Resistors are located in a V-shaped metal trough. Applying AC 350V for one
minute and should find no physical damage to the resistors, such as arc,
char ...etc.
7.5 Load Life:
The resistors arrayed are sent into the 70℃ oven, applying rated voltage at the
cycle of 1.5 hours ON, 0.5 hour OFF for 1000
+48
hours in total. Then, after removing
-0
the voltage, take the resistors out of the oven and left under normal temp. for one
hour cooling. The resistance value change rate between pre-and-post test shall
be within
±5%.
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ULTRA MINI SIZE METAL OXIDE FILM RESISTORS
7.6 Moisture-proof Load Life:
The resistors arrayed are placed into a constant temp./humidity oven at the temp.
of 40
±2℃
and the humidity of 90½95%, then rated power is applied for 1.5 hours
and cut off for 0.5 hour. The similar cycle will be repeated for 500
+24
hours in total
-0
(including cut-off time). Then remove the voltage, taking the resistors out of the
oven and leaving them at room temp. for one hour. The resistance value change
rate between pre-and-post test shall be within
±5%.
There also shall be no
evidence of remarkable change on appearance, and the marking shall not be
illegible.
7.7 Solder-ability:
The leads with flux are dipped in a melted solder of 235
±5℃
for 2 seconds, more
than 95% of the circumference of the lead wires shall be covered with solder.
7.8 Resistance to Soldering Heat:
Two leads are together dipped in a melted solder of 270
±5℃
for 10
±1
seconds,
or 350
±10℃
for 3.5
±0.5
seconds, Then remove the resistors and leaving them at
room temp. for one hour. The resistance value change rate between pre-and-post
test shall be within
±1%.
7.9 Nonflammability:
The resistors are applied the power of 16 times the rated wattage for 5 min. and
shall not get flame.
8. Others:
8.1 MG Form:
Unit: mm
RSU
2W
3W
L±1
9
15
D±1
3.5
5
P
15 ± 1.5
20 ± 2
H
7±1
10 ± 2
h±1
4.5
4.5
A ± 0.02
0.23
0.25
B ± 0.05
0.8
1
C ± 0.2
1.2
1.4
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