Type USF Ultra-Stable Low TC Film Resistors
200 Series and 300 Series
Page 1 of 2
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
•
Tolerance: ±0.01% or ±0.10%.
•
Specific standard resistance values are available that are most
200 Series —
ZERO Nominal TC
— Maximum Absolute TC 2 ppm/°C
300 Series —
ZERO Nominal TC
— Maximum Absolute TC 5 ppm/°C
•
300 Series “matched pairs” are available with ratio TC as tight as
•
Ceramic package provides cool operation.
0.5 ppm/°C. Contact Applications Engineering.
commonly required in high accuracy analog design. These values
were selected and optimized for produceability and performance.
Type USF 200 Series Ultra-Stable Resistors
•
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.
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.
Model Number
USF240
USF270
USF271
USF340
USF370
USF371
@
+85°C
•
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
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
Fig.
1
1
1
2
2
2
A
.750
±.020
(19.05
±.51)
1.500
±.020
(38.10
±.51)
1.500
±.020
(38.10
±.51)
Dimensions inches (mm)
B
.375
±.020
(9.53
±.51)
.500
±.020
(12.70
±.51)
C
.425 Max.
(10.8 Max.)
D
.600
±.020
(15.24
±.51)
1.350
±.020
(34.29
±.51)
1.350
±.020
(34.29
±.51)
.600
±.020
(15.24
±.51)
Wattage
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.
50
Ω
990 K
9.9 Meg
50
Ω
990 K
19.8 Meg
Max.
10 Meg
5 Meg
10 Meg
20 Meg
10 Meg
25 Meg
Temperature
Coefficient
2 ppm/°C
2 ppm/°C
2 ppm/°C
5 ppm/°C
5 ppm/°C
5 ppm/°C
.500
±.020
(12.70
±.51)
.375
±.020
(9.53
±.51)
.500
±.020
(12.70
±.51)
.750
±.020
(19.05
±.51)
1.500
±.020
(38.10
±.51)
1.500
±.020
(38.10
±.51)
.500
±.020
(12.70
±.51)
.520 Max.
(13.21 Max.)
.520 Max.
(13.21 Max.)
.395 Max.
(10.03 Max.)
.550 Max.
(13.97 Max.)
.550 Max.
(13.97 Max.)
1.350
±.020
(34.29
±.51)
1.350
±.020
(34.29
±.51)
e-mail: caddock@caddock.com • web: www.caddock.com
For Caddock Distributors listed by country see caddock.com/contact/dist.html
© 2003-2017 Caddock Electronics, Inc.
ELECTRONICS, INC.
Sales and Applications Engineering
17271 North Umpqua Hwy.
Roseburg, Oregon 97470-9422
Phone: (541) 496-0700
Fax: (541) 496-0408
28_IL134.01717
Type USF Ultra-Stable Low TC Film Resistors
200 Series and 300 Series
Standard Resistance Values:
50.0
Ω
100
Ω
200
Ω
250
Ω
350
Ω
500
Ω
900
Ω
1.00 K
2.00 K
2.50 K
5.00 K
9.00 K
10.0 K
20.0 K
25.0 K
50.0 K
90.0 K
99.0 K
100 K
200 K
Page 2 of 2
USF240 Standard Resistance Values:
Absolute Tolerance: ±0.01% or ±0.10%, Absolute TC: 2ppm/°C
250 K
500 K
1.00 Meg
2.00 Meg
USF270 Standard Resistance Values:
990 K
2.50 Meg 10.0 Meg
5.00 Meg
9.90 Meg
9.99 Meg
Fig. 1
USF 200 Series
Top View
A
Front View
.032 DIA.
(.81 DIA.)
B
.50
±.125
(12.70
±3.18)
Dimensions in inches
and (millimeters)
.160
±.030
(4.06
±.76)
C
Absolute Tolerance: ±0.01% or ±0.10%, Absolute TC: 2ppm/°C
USF271 Standard Resistance Values:
1.00 Meg 2.00 Meg 5.00 Meg
CADDOCK
USF24004
18
(seated height)
9.90 Meg 9.99 Meg 10.0 Meg
Absolute Tolerance: ±0.01% or ±0.10%, Absolute TC: 2ppm/°C
USF340 Standard Resistance Values:
400
Ω
500
Ω
700
Ω
1.00 K
1.80 K
2.00 K
4.00 K
5.00 K
10.0 K
18.0 K
20.0 K
40.0 K
50.0 K
90.0 K
99.0 K
100 K
180 K
198 K
200 K
400 K
Side View
.200
±.020
(5.08
±.51)
50.0
Ω
100
Ω
200
Ω
350
Ω
Absolute Tolerance: ±0.01% or ±0.10%, Absolute TC: 5ppm/°C
500 K
990 K
999 K
1.00 Meg
USF370 Standard Resistance Values:
990 K
1.98 Meg 4.00 Meg 9.90 Meg 10.0 Meg
1.00 Meg 2.00 Meg 5.00 Meg 9.99 Meg
2.00 Meg
4.00 Meg
5.00 Meg
9.90 Meg
9.99 Meg
10.0 Meg
19.8 Meg
19.98 Meg
20.0 Meg
D
Absolute Tolerance: ±0.01% or ±0.10%, Absolute TC: 5ppm/°C
Series Resistor must have the two “bonded” resistors in the package
connected in parallel on the circuit board as shown. This parallel connection
of the two resistors achieves the specified resistance with the specified
performance.
Circuit Board Trace
Circuit Board Trace
USF 200 Series Circuit Board Connection Note:
The Type USF 200
USF371 Standard Resistance Values:
19.8 Meg 19.98 Meg 20.0 Meg 25.0 Meg
Absolute Tolerance: ±0.01% or ±0.10%, Absolute TC: 5ppm/°C
Specifications:
Resistance Tolerance:
±0.01% or ±0.10 measured at +23°C ±2°C.
Absolute Temperature Coefficient:
TC referenced to +25°C,
∆R
taken at -40°C and +85°C.
Load Life Stability:
2,000 hours at +85°C at rated voltage, not to
exceed rated power,
∆R
(+0.015 ±0.015)% max.
10,000 hours at +85°C at rated voltage, not to exceed rated
power,
∆R
(+0.030 ±0.030)% max.
Fig. 2
USF 300 Series
A
Front View
CADDOCK
USF34004
12
.075
±.020
(1.91
±.51)
C
B
.50
±.125
(12.70
±3.18)
D
(seated height)
Thermal Shock:
Mil-Std-202 Method 107 condition A, except min.
temp. is -40°C,
∆R
±0.01% maximum.
Voltage Coefficient:
USF270 at 5 Meg, and USF271, USF370,
USF371 at resistances of 9 Meg or greater, 0.02 ppm/volt
maximum.
Shelf Life Stability:
Typical +(20ppm ±20ppm)/yr. after 1 year.
Extended shelf life (ten years) 10ppm/year maximum.
Operating Temperature:
-40°C to +85°C.
Leadwire:
Solder Coated Copper.
.032 DIA.
(.81 DIA.)
Side View
Dimensions in inches
and (millimeters)
Custom USF 200 Series and 300 Series Resistors:
USF 200 Series and 300 Series Resistors are available, for high
quantity applications, with custom performance:
• In the 200 Series, Absolute TC to as tight as 1ppm/°C is available
for certain resistances.
• Matched Ratio TC to as tight as 0.5ppm/°C for equal resistances.
• Matched Ratio TC can be provided in the 200 Series style “bonded”
Resistor pairs.
Ordering Information USF200 Series:
USF240 - 10.0 Meg - 0.01% - 2 ppm/°C
Model Number
Resistor Value
Tolerance
(0.01% or 0.10%)
Other Low TC Resistor Products from Caddock:
•
•
•
•
•
•
•
Type TF Low TC Ultra-Precision Film Resistors (1K to 125Meg)
Type TN Lab Grade Low TC Precision Film Resistors
Type TK Low TC Precision Radial-Lead Film Resistors
Type TG Low TC Precision High Voltage Resistors (up to 30KV)
T912 and T914 Low TC Ultra-Precision Resistor Networks
Type USVD Ultra-Stable Voltage Dividers (up to 2500V)
Type THV Precision High Voltage Dividers (up to 20KV)
Ordering Information USF300 Series:
USF370 - 990K - 0.10% - 5 ppm/°C
Model Number
Resistor Value
Tolerance
(0.01% or 0.10%)
e-mail: caddock@caddock.com • web: www.caddock.com
For Caddock Distributors listed by country see caddock.com/contact/dist.html
© 2003-2017 Caddock Electronics, Inc.
ELECTRONICS, INC.
Sales and Applications Engineering
17271 North Umpqua Hwy.
Roseburg, Oregon 97470-9422
Phone: (541) 496-0700
Fax: (541) 496-0408
28_IL134.01717
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