USF240 Datasheet, PDF (1/2 Pages) List of Unclassifed Manufacturers – Ultra-Stable Low TC Film Resistors

Page 1 of 2
Type USF Ultra-Stable Low TC Film Resistors
200 Series and 300 Series
New
Zero Nominal TC — Maximum Absolute TC to 2 ppm/°C, -40°C to +85°C ref. to +25°C
Absolute Tol. to ±0.01%, Resistance Range 50 Ohm to 25 Megohm, Voltage Ratings up to 2500 Volts
The USF Ultra-Stable Low TC Ultra-Precision Film Resistors were
developed to meet the requirements for increasing performance for
resistors in high performance analog electronics. Utilizing Caddock
proprietary resistance film systems, the Type USF resistors provide
the Lowest TC with the Widest Resistance Range and the Highest
Voltage Ratings available in the industry.
• Resistance Range 50 ohm to 25 Megohm.
• Temperature Coefficient -40°C to +85°C, referenced to +25°C
200 Series — ZERO Nominal TC — Maximum Absolute TC 2 ppm/°C
300 Series — ZERO Nominal TC — Maximum Absolute TC 5 ppm/°C
• Tolerance: ±0.01% or ±0.10%.
• Specific standard resistance values are available that are most
commonly required in high accuracy analog design. These values
were selected and optimized for produceability and performance.
• 300 Series “matched pairs” are available with ratio TC as tight as
0.5 ppm/°C. Contact Applications Engineering.
• Ceramic package provides cool operation.
Type USF Ultra-Stable Resistors are offered in standard resistance values
that are most commonly used in precision analog design. These standard
resistance values can be used in precise amplifier gain setting, precise
resistor bridge circuits, precise transducer sense circuits, and precise
voltage dividers with up to 2500 volt input voltage.
Type USF 200 Series Ultra-Stable Resistors
• Constructed with two selected USF 300 Series
Resistors bonded back to back to achieve
outstanding low Absolute Temperature Coefficient
performance. The resistors are to be connected in
parallel on the circuit board.
• ZERO Nominal TC — Max. Absolute TC: 2 ppm/°C,
-40°C to +85°C, referenced to +25°C
Extremely Low Power Coefficient (Wattage Coefficient): Type USF
resistors are constructed with an aluminum oxide ceramic sandwich
which provides great thermal conductivity. The ceramic sandwich
package very effectively minimizes the power coefficient drift. Power
coefficient is the resistance drift due to temperature rise in the element
caused by the power (wattage) dissipation in the resistor where the self-
heating temperature rise of the resistor element results in TC drift (temp.
rise in °C, times the temperature coefficient of the resistor). In the USF
package, heat is pulled away from the resistance material efficiently by
this ceramic sandwich package construction. Plastic molded Low TC foil
resistors cannot provide this outstanding benefit since the plastic impedes
the flow of heat, causing greater temperature rise at the resistor element
and greater self-heating related resistance drift due to power dissipation.
The USF 200 Series resistors provide a new level of performance with
near ZERO TC, very low power coefficient, wide resistance range, and
higher voltage ratings than is offered by other resistor technologies.
Type USF 300 Series Ultra-Stable Resistors
• ZERO Nominal TC — Max. Absolute TC: 5 ppm/°C,
-40°C to +85°C, referenced to +25°C
Model Number
USF240
USF270
USF271
USF340
USF370
USF371
Wattage
@ +85°C
0.33
0.75
0.75
0.33
0.75
0.75
Maximum
Continuous
Oper. Voltage
300
1,400
2,500
300
1,400
2,500
Resistance
Min.
Max.
50 Ω
10 Meg
990 K
5 Meg
9.9 Meg
10 Meg
50 Ω
20 Meg
990 K
10 Meg
19.8 Meg
25 Meg
Temperature
Coefficient
Fig.
A
2 ppm/°C
1
.750 ±.020
(19.05 ±.51)
2 ppm/°C
2 ppm/°C
1
1.500 ±.020
(38.10 ±.51)
1
1.500 ±.020
(38.10 ±.51)
5 ppm/°C
2
.750 ±.020
(19.05 ±.51)
5 ppm/°C
5 ppm/°C
2
1.500 ±.020
(38.10 ±.51)
2
1.500 ±.020
(38.10 ±.51)
Dimensions inches (mm)
B
C
.375 ±.020
(9.53 ±.51)
.425 Max.
(10.8 Max.)
.500 ±.020
(12.70 ±.51)
.500 ±.020
(12.70 ±.51)
.550 Max.
(13.97 Max.)
.550 Max.
(13.97 Max.)
.375 ±.020
(9.53 ±.51)
.395 Max.
(10.03 Max.)
.500 ±.020
(12.70 ±.51)
.500 ±.020
(12.70 ±.51)
.520 Max.
(13.21 Max.)
.520 Max.
(13.21 Max.)
D
.600 ±.020
(15.24 ±.51)
1.350 ±.020
(34.29 ±.51)
1.350 ±.020
(34.29 ±.51)
.600 ±.020
(15.24 ±.51)
1.350 ±.020
(34.29 ±.51)
1.350 ±.020
(34.29 ±.51)
Applications Engineering
17271 North Umpqua Hwy.
Roseburg, Oregon 97470-9422
Phone: [phone]
Fax: [phone]
© 2004 Caddock Electronics, Inc.
CADDOCK
e-mail: [e-mail] • web: www.caddock.com
For Caddock Distributors listed by country see caddock.com/contact/dist.html
Sales and Corporate Office
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Phone: [phone]
Fax: [phone]
28_IL134.1004