1268
Vishay Foil Resistors
Bulk Metal® Foil Technology
Precision Trimming Potentiometers,
3/8 Inch Square, RJ24 Style - Industrial Trimmer
FEATURES
• Temperature Coefficient of Resistance (TCR):
± 20 ppm/°C Max2). (- 55 °C to + 150 °C Ref. at 25 °C);
Through the wiper3); ± 50 ppm/°C
• Load Life Stability: 0.1 % Typical ΔR, 1.0 % Maximum
ΔR under Full Rated Power at + 85 °C for 1000 Hours
• Settability: 0.1 %
• Setting Stability: 0.1 % Typical1); 0.5 % Maximum1), ΔSS
• Power Rating4): 0.25 watts at + 85 °C
Product may not be to scale
• Resistance Range: 20 Ω to 5 kΩ
• Resistance Tolerance: ± 10 %
TABLE 1 - MODEL SELECTION†
MODEL
1268
TERMINATION STYLE
W-Edge Mount, Top Adjust
X-Edge Mount, Side Adjust
AVERAGE
WEIGHT (g)
STANDARD RESISTANCE
VALUES (in Ω)
STANDARD
TOLERANCES
POWER RATING
at + 85 °C AMBIENT
NO. OF
TURNS
0.4
20, 50, 100, 200, 500,
1K, 2K, 5K
± 10 %
0.25 W
21 ± 2
NOTES:
ADDITIONAL SPECIFICATIONS:
† See Figure 1, next page.
• Contact Resistance Variation - CRV (noise): 10 Ω Maximum5)
1. Maximum is 1.0 % A.Q.L. standard for all specifications except
TCR. (For TCR information see notes 2 and 3). “Typical” is a
designers reference which represents that 85 % of the lots
supplied, over a long period of time, will be at least the figure
stated or better.
2. Maximum TCR applies to the 3 s (sigma) limit or 99.73 % of a
production lot. (Measured end-to-end with wiper off the element.)
3. Measurements of TCR through the wiper are influenced more by
setting stability and the percentage of the total resistance in use
(at the wiper) than by fundamental resistance change due to
temperature alone. The parameter shown is a 2 s distribution
typifying the behavior of the device when used with 40 % or more
of the total resistance in use.
4. Derated linearly from full power at + 85 °C to zero (0) watts at
+ 150 °C. See Figure 2, next page.
5. Independent of resistance value 3 W maximum available on
special request.
Special Available Options:
Special marking
Burn-in and screening operations
• Hop-off: 0.25 % Typical; 1.0 % Maximum
• Operating Temperature Range: - 55 °C to + 150 °C
• Adjustment Turns: 21 ± 2
• Mechanical Stops: Wiper Idles - No Discontinuity
TABLE 2 - ORDERING INFORMATION - 1268 SERIES PARTS
Please specify Vishay Model 1268 Precision Trimming
Potentiometers as follows:
MODEL
NO.
TERMINATION
STYLE
RESISTANCE
VALUE
TOLERANCE
W
100R
10 %
1268
NOTES:
See Table 1 for details.
See Figure 1, next page for Standard Marking.
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1
For any questions, contact: foil@vishaypg.com
Document Number: 63059
Revision: 24-Mar-10
1268
Vishay Foil Resistors
FIGURE 1 - SCHEMATIC AND DIMENSIONS in inches (millimeters)
1268W
0.081 ± 0.010" (2.08 ± 0.25 mm)
0.080" (2.03 mm)MAXIMUM
MAX
VISHAY
0.420" (10.67 mm) MAXIMUM
MAX
2
CW
0.015" (0.38 mm) MIN
MINIMUM
0.300" (7.62 mm) MINIMUM
MIN
3
1
3 PINS
0.024 ± 0.006" (0.61 ± 0.15 mm) DIAMETER
DIA
STANDARD MARKING
Model No.
Date Code
0.090 ± 0.005"
(2.29 ± 0.13 mm) DIA
Resistance Value
0.170 ± 0.025"
(4.32 ± 0.64 mm)
± 0.010" (± 0.25 mm) C
Tolerance
0.075 ± 0.010"
(1.91 ± 0.25 mm)
0.100 ± 0.005"
(2.54 ± 0.13 mm)
0.375 ± 0.015"
(9.53 ± 0.38 mm)
0.187 ± 0.020"
(4.75 ± 0.51 mm)
NOTES
Adjustment screw 0.090 Inches
1268X
(2.30 mm) diameter with 0.020
0.080" (2.03 mm) MAX
MAXIMUM
Inches (0.51 mm) x 0.031 Inches
(0.80 mm) slot. Model 1268 has
0.081 ± 0.010"
(2.08 ± 0.25 mm)
0.420" (10.67 mm) MAX
VISHAY
solder plated copper terminal
2
pins. 0.024 Inches (0.61 mm)
MAXIMUM
diameter, 0.300 Inches (7.62 mm)
CW
0.015" (0.38 mm) MIN
MINIMUM
0.300" (7.62 mm) MIN
MINIMUM
1
length minimum.
3
3 PINS
0.024 ± 0.006" (0.61 ± 0.15 mm) DIA
DIAMETER
0.075 ± 0.010"
(1.91 ± 0.25 mm)
0.170 ± 0.025"
(4.32 ± 0.64 mm)
± 0.010" (± 0.25 mm) C
0.090 ± 0.005"
(2.29 ± 0.13 mm) DIA
0.100 ± 0.005"
(2.54 ± 0.13 mm)
0.375 ± 0.015"
(9.53 ± 0.38 mm)
0.187 ± 0.020"
(4.75 ± 0.51 mm)
Percent of Rated Power
FIGURE 2 - POWER DERATING CURVE
+ 85 °C
+ 100
+ 75
+ 50
+ 25
0
- 75
- 50
- 25
0
+ 25
+ 50 + 75 + 100 + 125 + 150 + 175
Ambient Temperature °C
Document Number: 63059
Revision: 24-Mar-10
For any questions, contact: foil@vishaypg.com
www.foilresistors.com
2
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Vishay Precision Group, Inc.
Disclaimer
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Copyright Vishay Precision Group, Inc., 2014. All rights reserved.
Document No.: 63999
Revision: 15-Jul-2014
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