Pulse Withstanding
Chip Resistors
PWC Series
sExcellent pulse withstand performance
sImproved working voltage
sImproved power rating
sStandard chip sizes (0805 to 2512)
sCustom designs available
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Electrical Data
07. 08
A subsidiary of
TT electronics plc
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Thermal Impedance °C/W 220 160 80 50
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Physical Data
Construction
Thick film resistor material, overglaze and organic protection
are screen printed on a 96% alumina substrate. Wrap-around
terminations have an electroplated nickel barrier and solder
coating, this ensures excellent ‘leach’ resistance properties
and solderability.
Marking
Components are not marked. Reels are marked with type,
value, tolerance, date code and quantity.
Solvent Resitance
The body protection is resistant to all normal industrial
cleaning solvents suitable for printed circuits.
Dimensions of PWC resistors are given below in mm and weight in g
L W T max A B C Wt.
0805 2.0±0.3 1.25±0.2 0.6 0.3±0.15 0.9 min 0.3±0.1 0.009
1206 3.2±0.4 1.6±0.2 0.7 0.4±0.2 1.7 min 0.4±0.15 0.020
2010 5.1±0.3 2.5±0.2 0.8 0.6±0.3 3.0 min 0.6±0.25 0.036
2512 6.5±0.3 3.2±0.2 0.8 0.6±0.3 4.4 min 0.6±0.25 0.055
T
W
A
A
B
L
Wrap-around terminations
(3 faces)
*Recommended minimum pad & adjacent trace area for each termination for rated power dissipation on FR4 PCB
Welwyn Components
12. 08
Pulse Withstanding
Chip Resistors
PWC Series
© Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com 07. 08
Performance Data
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Load at rated power: 1000 hours at 70°C ∆52.01%R
Shelf life test: 12 months at room temperature ∆20.01.0%R
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Overload: 6.25 x rated power for 2 seconds ∆1.01%R
Dry heat: 1000 hours at 155°C ∆2.01%R
Long term damp heat ∆52.01%R
Temperature rapid change ∆50.052.0%R
Resistance to solder heat ∆50.052.0%R
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Note: A 0.01 Ohm addition to be added to the performance of all resistors <10 Ohms.
Welwyn Components
Pulse Performance Data
1.2/50µs Lightning Surge
10
100
1000
10000
1 10 100 1000 10000 100000 1000000 10000000
Value (ohms)
Peak voltage (volts)
0805
1206
2010
2512
10/700µs Lightning Surge
10
100
1000
10000
1 10 100 1000 10000 100000 1000000 10000000
Value (ohms)
Peak Voltage (Volts)
0805
1206
2010
2512
Lightning Surge
lightning surge resistors are tested in
accordance with IEC 60 115-1 using
both 1.2/50µs and 10/700µs pulse shapes.
10 pulses are applied. The limit of
acceptance is a shift in resistance of less
than 1% from the initial value.
12. 08
Pulse Withstanding
Chip Resistors
PWC Series
© Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com 07.08
Pulse Performance Data
Welwyn Components
Single Pulse
1
10
100
1000
10.10.010.0010.0001
Pulse Duration ti (s)
Pulse Power P (W)
0805
1206
2010
2512
Continuous Pulses
0.1
1
10
100
10.10.010.0010.0001
Pulse Duration ti (s)
Pulse Power P (W)
0805
1206
2010
2512
Pulse Voltage
10
100
1000
10000
10.10.010.0010.0001
Pulse Duration ti (s)
Pulse Voltage (Volts)
0805
1206
2010
2512
Single Impulse
The single impulse graph is the result of
50 impulses of rectangular shape
applied at one minute intervals. The
limit of acceptance was a shift in
resistance of less than 1% from the
initial value.
Continuous Load Due to
Repetitive Pulses
The continuous load grpah was
obtained by applying repetitive
rectangular pulses where the pulse
period was adjusted so that the average
power dissipated in the resistor was
equal to its rated power at 70°C. Again
the limit of acceptance was a shift in
resistance of less than 1% from the
initial value.
12. 08
Temperature Derating Curve
125
Ambient Temperature /°C
% of Rated Power
75
50
25
0
100
5510751-
Pulse Withstanding
Chip Resistors
PWC Series
© Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Thermal Performance Data
12. 08
Packaging
0805 and 1206 PWC series resistors are
supplied on 8mm carrier tape and 7 inch
reels as per IEC 286-3, quantity per
reel; 3000.
2010 and 2512 PWC series resistors are
supplied on 12mm carrier tape and 7
inch reels as per IEC 286-3, quantity per
reel; 2010 : 3000pcs; 2512 : 1800pcs.
Reels of 1000pcs are available on
request.
PWC resistors are ideally suited for handling by automatic
methods due to their rectangular shape and the small
dimensional tolerances. Electrical connection to a ceramic
substrate or to a printed circuit board can be made by reflow
or wave soldering of wrap-around terminations.
Wrap-around terminations provide good leach properties and
ensure reliable contact. Due to the robust construction, the
PWC can be immersed in the solder bath for 30 seconds at
260°C. This enables the resistor to be mounted on one side
of a printed circuit board and wire-leaded components
applied on the other side.
PWC resistors themselves can operate at a maximum
temperature of 155°C. For soldered resistors, the joint
temperature should not exceed 110°C. This condition is met
when the stated power levels at 70°C and recommended pad
and trace areas are used. Allowance should be made if
smaller areas of copper are used.
A full Application Note on the PWC Series is available.
Ordering Procedure
Specify type reference etc as shown in this example of
PWC2512 10K ohms 1%.
Temperature Rise Curves
80
Power Dissipation /W
Temperature Rise /°C
60
40
20
0
0 0.5 1 1.5
0805
1206
2010
2512
Application Notes
2.5 ± 0.5
13 ± 0.5
33 ± 1.0
Marking
0.8 ± 0.15
80 ± 2
178 ± 2
9.0
8mm tape: 9mm ± 0.5
12mm tape: 13mm ± 0.5
+ 0.1
- 0.15
P1
A0
B0
D1
D0
P0
P2
G F
W
E
T2
T1
K0
T
Tape dimensions in mm
W P1 P0 P2 D0 D1 E F A0 B0 K0 T T1 T2
±0.3 ±0.1 ±0.1 ±0.05 ±0.1 ±0.2 ±0.1 ±0.05 ±0.1 ±0.1 ±0.1 ±0.05 nom ±0.15
0805 8 4 4 2 1.5 1 1.75 3.5 1.65 2.45 0.8 0.2 0.05 1.1
1206 8 4 4 2 1.5 1 1.75 3.5 1.95 3.55 1.0 0.2 0.05 1.3
2010 12 4 4 2 1.5 1.5 1.75 5.5 2.79 5.89 0.91 0.28 0.06 1.21
2512 12 8 4 2 1.5 1.5 1.75 5.5 3.61 6.96 1.17 0.28 0.06 1.45
Type PWC 2512 - 10K F
Size
Value (use IEC62 code)
Tolerance (use IEC62 code)
D 0.5%
F 1%
J 5%
Welwyn Components
