Approval sheet
WK25Z, WK20Z
±
1%,
±
5%
Ultra High Voltage Chip Resistors
Size 2512, 2010
Page 1 of 8
ASC_WKxxZ_V01
Jul. 2011
Approval sheet
FEATURE
1. Special material and design for endurance rush voltage 3,000V
2.
Compatible with flow and reflow soldering
3.
Suitable for lead free soldering.
4. High limiting element voltage up to 2,000V
APPLICATION
•
•
•
•
Power supply
Automotive industry
Measurement instrument
Back light inverter
Medical or Military equipment
•
DESCRIPTION
The resistors are constructed in a high grade ceramic body (aluminum oxide). Internal metal electrodes are
added at each end and connected by a resistive paste that is applied to the top surface of the substrate. The
composition of the paste is adjusted to give the approximate resistance required and the value is trimmed to
nominated value within tolerance which controlled by laser trimming of this resistive layer.
The resistive layer is covered with a protective coat. Finally, the two external end terminations are added. For
ease of soldering the outer layer of these end terminations is a Tin (lead free) alloy.
Fig 1. Construction of Chip-R
Page 2 of 8
ASC_WKxxZ_V01
Jul. 2011
Approval sheet
QUICK REFERENCE DATA
Item
Series No.
Size code
Resistance Tolerance
Resistance Range
TCR (ppm/°C)
Max. Dissipation at T
amb
=70°C
Max. Operation Voltage
(DC or RMS)
Max. Overload Voltage
(DC or RMS)
Operation temperature
Note:
1.
2.
This is the maximum voltage that may be continuously supplied to the resistor element, see “IEC publication
60115-8”
Max. Operation Voltage : So called RCWV (Rated Continuous Working Voltage) is determined by
WK25Z
2512 ( 6432 )
±20%, ±10%, ±5%
(E24)
General Specification
WK20Z
2010 ( 5025 )
4.7MΩ ~ 16MΩ
±200
1W
2,000V
4,000V
-55 ~ +125’C
1.0MΩ ~ 16MΩ
±200
1/2 W
1,500V
3,000V
RCWV
=
Rated Power
×
Resistance Value
or Max. RCWV listed above, whichever is lower.
MECHANICAL DATA (unit : mm)
105
Symbol
L
W
T
Tt
Tb
WK25Z
6.30
±
0.15
3.20
±
0.15
0.55
±
0.15
0.60
±
0.20
0.60
±
0.20
WK20Z
5.00
±
0.15
2.50
±
0.15
0.55
±
0.15
0.50
±
0.20
0.60
±
0.20
Page 3 of 8
ASC_WKxxZ_V01
Jul. 2011
Approval sheet
MARKING
For E24 series, each resistor is marked with a three–digit code on the protective coating to designate the
nominal resistance value.
Example:
105 = 1MΩ
105
FUNCTIONAL DESCRIPTION
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”.
Derating curve
The power that the resistor can dissipate depends on the operating temperature; see Fig.2
Figure 2
Maximum dissipation in percentage of rated power as a
function of the ambient temperature
MOUNTING
Chip placement can be on ceramic substrates and printed-circuit boards (PCBs).
Electrical connection to the circuit is by individual soldering condition.
The end terminations guarantee a reliable contact.
Page 4 of 8
ASC_WKxxZ_V01
Jul. 2011
Approval sheet
SOLDERING CONDITION
The robust construction of chip resistors allows
them to be completely immersed in a solder bath
of 260°C for 10 seconds. Therefore, it is possible
to mount Surface Mount Resistors on one side of
a PCB and other discrete components on the
reverse (mixed PCBs).
Surface Mount Resistors are tested for
solderability at 235°C during 2 seconds. The test
condition for no leaching is 260°C for 30 seconds.
Typical examples of soldering processes that
provide reliable joints without any damage are
given in Fig 3.
Fig 3. Infrared soldering profile
CATALOGUE NUMBERS
The resistors have a catalogue number starting with .
WK25
Size code
WK25
WK20
: 2512
: 2010
Z
Type code
Z :Ultra High
Voltage
105
Resistance code
5%, E24: 2 significant digits
followed by no. of zeros
1MΩ
10MΩ
= 105_
= 106
J
Tolerance
J :
±5%
K :
±10%
M :
±20%
T
Packaging code
T : 7” inch reel
L
Termination code
L
=
Sn base
(lead free)
Tape packaging
WK25；WK20: 12mm width plastic taping 4,000pcs per reel.
Page 5 of 8
ASC_WKxxZ_V01
Jul. 2011
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