Surface Mounted
Thermistors
PTCR Series
Welwyn Components
•
TCR’s up to +3500 ppm
•
Custom designs available
•
Solder terminations have a nickel barrier layer
•
Resistance range 10 ohms to 800 ohms
•
Tolerances down to 2%
•
Available in 0805 and 1206 sizes
Electrical Data
Commercial
Power rating at 70°C
Resistance range
Limiting element voltage
TCR -55°C to 155°C
Resistance tolerance at 20°C
Ambient temperature range
Values
Thermal impedance
watts
ohms
volts
ppm/°C
%
°C
ohms
°C/watt
360
2, 5, 10
-55 to 155
E24 & E96 preferred
200
Any value to order
For 10 devices
mounted on a
50 x 25mm p.c.b. area
PTCR 0805
0.1
10R to 400R
100
PTCR 1206
0.25
10R to 800R
200
See table below
Notes
Variation of TCR within Value Range
Value range (ohms)
10 to <25
25 to <50
50 to <100
10 to <200
200 to <400
400 to <800
TCR (ppm/°C)
3500 ± 10%
3100 ± 10%
2900 ± 10%
2700 ± 15%
2400 ± 15%
2200 ± 15%
Resistance (ohms)
10000
1000
800R
100
10
1
-55
10R
-15
25
65
105
Temperature
°C
145
Physical Data
Dimensions (mm) and weight (g)
Style
0805
1206
L
W
T max
0.6
0.7
A
B*
Wt nom
0.009
A
Wrap-around terminations
(3 faces)
T
B
L
2.0 ± 0.3 1.25 ± 0.2
3.2 ± 0.4 1.6 ± 0.2
0.3 ± 0.15 0.9 min
0.4 ± 0.2
1.7 min
0.0090
A
W
*This dimension determines the number of conductors which may pass under the surface mounted device.
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.
A subsidiary of
TT electronics plc
Issue C · 08.04
© 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
37
Surface Mounted
Thermistors
PTCR Series
Construction
Thick film resistor material, overglaze and organic protection
are screen printed on a 96% alumina substrate.
Welwyn Components
Marking
All relevant information recorded on the primary package or
reel.
Terminations
Wrap-around terminations are suitable for soldering.
Solderability
Wrap-around terminations have an electroplated nickel barrier
and solder coating. This ensures excellent leach resistance
properties and solderability. They will withstand immersion in
solder at 260°C for 10 seconds.
Solvent Resistance
The chips are resistant to all normal industrial cleaning fluids
suitable for printed circuits.
Performance Data
Maximum
Load at rated power: 1000 hours at 70°C
Shelf life: 12 months at room temperature
Derating from rated power at 70°C
Dry heat: 1000 hours at 155°C
Climatic category
Long term damp heat
Temperature rapid change
Resistance to solder heat
Voltage proof
∆R%
∆R%
∆R%
volts
3
2
2
500
∆R%
2.5
55 / 155 / 56
1
0.5
0.5
∆R%
∆R%
5
3
Zero at 155°C
1
Typical
1
0.5
Application Notes
Operating Temperature Range
The chips themselves can operate at a maximum
temperature of 155°C (see performance claims above). For
soldered chips, the joint temperature should not exceed
110°C. This condition is met when the stated power levels
at 70°C are used.
Packing
As standard 3000 chips are supplied taped and reeled on
8mm tape to IEC 286-3.
Ordering Procedure
Specify type reference, value and tolerance as shown in
this example of PTCR1206 400R 2%:
Type
Resistance value
(IEC62 code)
Tolerance
(IEC62 code)
F
G
J
1%
2%
5%
Mounting
This chips resistor is ideally suited for handling by
automatic methods due to its rectangular shape and small
dimensional tolerances. Electrical connection to a ceramic
substrate or to a printed circuit board can be made by flow
or reflow soldering of wraparound terminations. The
terminations provide good ‘leach’ properties and ensure
reliable contact. Due to the robust construction the resistor
chip can be immersed in a solder bath for 10 seconds at
260°C. This enables the resistor to be mounted on one
side of a printed circuit board and wire-leaded components
on the other side.
1206
400R
G
© 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
38
Issue C · 08.04
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