Type USFS High Voltage, Ultra-Stable, Low TC Selected Resistor Sets0 pages

Type USFS High Voltage, Ultra-Stable,
Low TC Selected Resistor Sets
New

Total Set Resistance up to 100 Megohm with Absolute TC of 2 ppm/°C
Voltage Ratings up to 5000 Volts DC - Custom Selected Resistor Sets Available

Type USFS - Ultra-Stable Selected Resistor Sets
are designed for use in High Voltage Systems
that require the very best temperature stability
and long term stability. These Selected Resistor
Sets are manufactured with Caddock’s Tetrinox®
Resistance Film System.
The individual USF Style resistors that form
these Ultra-Stable Selected Resistor Sets are
individually characterized using automated data
acquisition systems and then selected to form
a Set Resistance with an Absolute Temperature
Coefficient (TC) of 2 ppm/°C maximum.
The low Voltage Coefficient (VC) of the USF370
and USF371 Style resistors used in these selected
resistor sets achieves excellent voltage stability
over the operating voltage range.
Multiple USFS Selected Resistor Sets can be
used in series to form a string of resistors that
achieves a higher total resistance and a higher
voltage rating with 2 ppm/°C overall temperature
coefficient. For Custom Selected Resistor Sets
contact Applications Engineering.
Specifications for the Selected Resistor Sets:

3 kV DC

3

USFS-5-370-50M-B2

5 kV DC

5

USFS-5-371-100M-B2

5 kV DC

5

All specifications are valid for the Set Resistance, which is formed
by the series connection of the resistors in the selected Resistor
set.
1

Operating Voltage: The continuous operating voltage for the
set of resistors connected in series. This continuous voltage
may be exceeded by a maximum of 10%.

2

Number of Resistors: The number of resistors in each
Selected Resistor Set, described by the Caddock Part Number.

3

Set Resistance: The total resistance of the set of resistors
connected in series.

4

Set Tolerance: The Tolerance of the Set Resistance, measured
at low voltage (DC) at +23°C ±2°C.

5

Set TC: The Temperature Coefficient of the Set Resistance,
measured at +10°C and +50°C, ref. to +25°C.

6

Set VC: The Voltage Coefficient of the Set Resistance,
measured at 10% and 100% of the Operating Voltage.

Storage Temperature Range: -35°C to +85°C.

High Voltage Design Note: The specifications for these high
voltage resistor sets are based upon the proper high voltage field
stress management, thermal design, and material selection for the
housing which encloses the high voltage resistor set. The design
of the housing is the responsibility of the user. These resistors are
compatible with many high voltage potting materials, but issues
regarding potting material adhesion, bubble free potting, and
electrical insulation/isolation are the responsibility of the user.

Dielectric Absorption: The USF resistors are engineered by
Caddock to minimize dielectric absorption. The circuit board, potting,
or encapsulation materials that are in contact with, or in circuit with
the USF resistors, can exhibit dielectric absorption behavior that can
affect the performance of the circuit. The user is responsible for the
selection of materials and the design so that dielectric absorption and
its effects on the performance of the circuit are minimized.
Applications Engineering and Sales
17271 North Umpqua Hwy.
Roseburg, Oregon 97470-9422
Phone: (541) 496-0700
Fax: (541) 496-0408
© 2012 Caddock Electronics, Inc.

10 Meg

6
Set
VC

Set
Schematic

0.10%

2 ppm/°C

0.008 ppm/V

Fig. 1A

0.10%

2 ppm/°C

0.005 ppm/V

Fig. 1B

100 Megohm

USFS-3-370-30M-B2

5
Set
TC

50 Megohm

2
Number of
Resistors

4
Set
Tolerance

30 Megohm

1
Operating
Voltage

Model Number

0.10%

2 ppm/°C

0.005 ppm/V

Fig. 1C

3
Set
Resistance

10 Meg

10 Meg

= 30 Meg
Figure 1A: Schematic of the three 10 Megohm USF370 Style resistors in a
USFS-3-370-30M-B2 Selected Resistor Set, which are connected in series to
form the 30 Megohm Resistance.
10 Meg

10 Meg

10 Meg

10 Meg

10 Meg

= 50 Meg

Figure 1B: Schematic of the five 10 Megohm USF370 Style resistors in a
USFS-5-370-50M-B2 Selected Resistor Set, which are connected in series to form
the 50 Megohm Resistance.
20 Meg

20 Meg

20 Meg

20 Meg

20 Meg

= 100 Meg

Figure 1C: Schematic of the five 20 Megohm USF371 Style resistors in a
USFS-5-371-100M-B2 Selected Resistor Set, which are connected in series to
form the 100 Megohm Resistance.

Figure 2 and Table: Physical Dimensions and Specifications of the individual
USF370 and USF371 Style Resistors that form USFS Selected Resistor Sets
1.500 ±0.020
(38.10 ±0.51)
CADDOCK
USFS-5-370-50M-B2
10.0 MEG DATE CODE

0.032 Dia.
(0.81)

0.075 ±0.020
(1.91 ±0.51)
0.500 ±0.020
(12.70 ±0.51)
0.50 ±0.125
(12.70 ±3.18)

1.350 ±0.020
(34.29 ±0.51)

Resistor Style

Resistance

Tolerance

TC

USF370 Style

10 Meg

±0.20%

±10 ppm/°C

USF371 Style

20 Meg

±0.20%

±10 ppm/°C

e-mail: caddock@caddock.com • web: www.caddock.com
For Caddock Distributors listed by country see caddock.com/contact/dist.html

Corporate Office
1717 Chicago Avenue
Riverside, California 92507-2364
Phone: (951) 788-1700
Fax: (951) 369-1151
L-423.1012