VCS331Z, VCS332Z, VFP4Z, CSNG
Vishay Foil Resistors
Bulk Metal
®
Z-Foil Technology Ultra High-Precision 4-Terminal
Power Current Sensing Resistors with TCR as Low as 0.05 ppm/°C,
Power up to 10 Watts and Thermal Stabilization of <1s
FEATURES
• Low temperature coefficient of resistance (see figure 4):
• 0.05 ppm/°C typical (0°C to +60°C)
• 0.2 ppm/°C typical (–55°C to +125°C, +25°C ref.)
• Resistance range: 0R25 to 500R
• Resistance tolerance: to ±0.01%
•
Power rating: 10W on heatsink(1) at +25°C;
3W in free air at +25°C (see Table 2)
• Load life stability:
• ±0.005% (50 ppm) typical, 3W on heatsink at
+25°C, 2000h
• ±0.01% (100 ppm) typical, 3W in free air at
+25°C, 2000h
• ± 0.01% typical (100 ppm), 10W on heatsink at
+25°C, 2000h
• Vishay Foil Resistors are not restricted to standard
values; specific “as required” values can be supplied at
no extra cost or delivery (e.g. 1R2345 vs. 1R)
•
Rapid ΔR stabilization under transient loads (see
Figure 2)
•
Thermal resistance: 6°C/W
• Electrostatic discharge (ESD) at least to 25 kV
• Rise time: 1 ns, effectively no ringing
•
Tenfold improvement of power coefficient of
resistance (PCR): 4 ppm/W (see Figure 3)
• Thermal stabilization time <1s (nominal value achieved
within 10 ppm of steady state value)
• Voltage coefficient: <0.1 ppm/V
• Current noise: 0.010 μV
RMS
/V of applied voltage
(<–40 dB)
• Inductance: 0.1 μH maximum; 0.08 μH typical
• Thermal EMF: 0.1 μV/°C (see Table 3)
• Non-inductive, non-capacitive design
• Pattern design minimizing hot spots
Note
(1) Heatsink—aluminum (6” L x 4” W x 2” H x 0.04” THK)
VCS331Z
VCS332Z
VFP4Z
CSNG
INTRODUCTION
The most precise measuring of electrical current is
achieved by the current sensing resistor method. The
precision and speed of response to changing current
depend on thermal stability of the resistor, as determined
by its low temperature coefficient of resistance (TCR) and
related power coefficient of resistance (PCR), as well as
its net reactance.
VCS331Z, VCS332Z, and VFP4Z (0R25 to 500R)
This series should be selected where rapid ΔR
stabilization and resistance stability under transient power
conditions is required. These products achieve optimum
performance when mounted on a chassis or cooled heat
sink. The Z-Foil technology provides extremely low PCR
under defined conditions (see Figure 2 and Figure 3). The
low absolute TCR provided by the Z-Foil technology is
measured over the temperature range of –55°C to +125°C
or 0°C to +60°C, +25°C reference (see Figure 4).
All of these devices utilizing the Z-Foil technology are
provided with a true 4-terminal Kelvin connection. This is
a must for precise current sensing when the resistance
value is less than 100Ω (see Figure 6).
CSNG — New Generation of
Power Current Sense Resistors (>0R005)
Custom high power designs can be developed for your
specific applications. Vishay Foil Resistors (VFR) recently
introduced New Generation of Power Current Sense
Resistors (CSNG) with short thermal setting time, long-
term stability, high power to 20W and absolute TCR to
±0.5 ppm/°C maximum (see page 5).
For more information, please contact Application
Engineering Department at foil@vishaypg.com.
*Pb containing terminations are not RoHS compliant; exemptions
may appy
Document No.: 63240
Revision: 13-Jun-2013
FIGURE 1—TRIMMING TO VALUES
(conceptual illustration)
Interloop
Capacitance
Reduction
in Series
Mutual
Inductance
Reduction due
to Opposing
Current in
Adjacent Lines
Current Path
Before Trimming
Current Path
After Trimming
Trimming Process
Removes this Material
from Shorting Strip Area
Changing Current Path
and Increasing Resistance
Note:
Foil shown in black, etched spaces in white
For questions, contact
foil@vishaypg.com
www.vishayfoilresistors.com
1
VCS331Z, VCS332Z, VFP4Z, CSNG
Vishay Foil Resistors
FIGURE 2 – RAPID STABILIZATION
RESISTANCE DEVIATION, ppm
15
10
5
0
–5
–10
–15
0
20
40
60
80
100
TIME, s
RESISTANCE CHANGE UNDER LOAD AT 10 WATTS
MOUNTED ON COOLED HEAT SINK HELD AT + 25 °C
120
140
160 180 200
FIGURE 4 – TYPICAL RESISTANCE/
TEMPERATURE CURVE (Z-FOIL)
+ 500
+ 400
+ 300
+ 200
+ 100
∆R
0
R
(ppm)
- 100
- 200
- 300
- 400
- 500
- 55
0.05 ppm/°C
- 0.1 ppm/°C
- 0.16 ppm/°C
- 25
0
+ 25
0.1 ppm/°C
0.14 ppm/°C
0.2 ppm/°C
+ 60 + 75
+ 100 + 125
Ambient Temperature (°C)
TCR Chord Slopes for Different Temperature Ranges
FIGURE 3 – POWER COEFFICIENT (PCR)
RESISTANCE DEVIATION, ppm
60
40
20
0
–20
–40
–60
0
1
2
5
APPLIED POWER, W
8
10
FIGURE 5 – POWER DERATING CURVE
RATED POWER (%)
100
75
50
25
0
- 55 °C
+ 25 °C
- 50
0
+ 50
+ 100
+ 150
+ 200
AMBIENT TEMPERATURE
RESISTANCE CHANGE VS APPLIED POWER
MOUNTED ON COOLED HEAT SINK HELD AT + 25 °C
FIGURE 6 – KELVIN CONNECTION
Kelvin, 4-terminal, connections are utilized for these
low ohmic value products to measure a precise voltage
drop across the resistive element. In these applications
the contact resistance, lead resistance, and their TCR
effect may be greater than that of the element itself and
could cause significant errors if the standard 2-terminal
connection is used. Figure 6 shows a high impedance
measurement system where r
5
approaches infinity and I
m
approaches zero resulting in negligible IR drop through r
3
and r
4
which negates their lead resistance and their TCR
effect. With the voltage sense leads E
1
and E
2
inside of r
1
and r
2
the resistance and TCR effect of the current leads,
I
1
and I
2
are negated and only the resistance and TCR of
the element R are sensed. This method of measurement is
essential for precise current sensing.
r
1
I
1
E
1
r
3
I
m
0
R
E
2
r
4
r
2
I
2
r
5
8
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foil@vishaypg.com
Document No.: 63240
Revision: 13-Jun-2013
VCS331Z, VCS332Z, VFP4Z, CSNG
Vishay Foil Resistors
FIGURE 7—STANDARD IMPRINTING AND DIMENSIONS
in inches (millimeters)
VFP4Z
1.575 ± 0.016 (40 ± 0.4)
1.181 ± 0.016 (30 ± 0.4)
VFR
VFP-4Z
(Value)
(Tol.)
B(Date Code)
0.197 (5)
0.150 ± 0.004
(3.8 ± 0.1)
0.394 ± 0.008
(10 ± 0.2)
Lead Dia.
0.025 (0.633)
Solder Coated
Copper
0.276
- 0.008
(7.0
- 0.2
)
0.118 (3)
+ 0.004
+ 0.1
0.787 ± 0.016
(20 ± 0.4)
1.00 Min.
(25.4 Min.)
I1 E1 E2
I2
0.200 [x3] (5.08)
VCS331Z
0.138 (3.5)
NOMINAL
1.340 ± 0.008 (34.0 ± 0.2)
0.701 ± 0.008
(17.8 ± 0.2)
0.087 (2.2)
MAXIMUM
0.210 (5.33)
MAXIMUM
VCS332Z
1.340 ± 0.008 (34.0 ± 0.2)
0.701 ± 0.008
(17.8 ± 0.2)
0.138 (3.5)
NOMINAL
0.087 (2.2)
MAXIMUM
0.210 (5.33)
MAXIMUM
1.063 (27.0)
MAXIMUM
0.197 ± 0.008
(5.0 ± 0.2)
VFR
VCS331Z
0R2000 1 %
B(Date Code)
I
1
E
1
0.16 (0.4) E I
NOMINAL
2
2
1.024 (26.0)
MAXIMUM
VFR
VCS332Z
8R2000 0.1 %
B(Date Code)
0.032 (0.8)
NOMINAL
0.197 ± 0.008
(5.0 ± 0.2)
0.040 (1.0)
NOMINAL
0.040 (1.0)
NOMINAL
0.216 (5.5)
MINIMUM
0.689 ± 0.020 (17.5 ± 0.5)
1.083 ± 0.20 (27.5 ± 0.5)
0.689 ± 0.020 (17.5 ± 0.5)
1.083 ± 0.20 (27.5 ± 0.5)
TABLE 1 – RESISTANCE VALUE VS. TOLERANCE
RESISTANCE RANGE (Ω)
10 to 500
5 to <10
2 to <5
1 to <2
0.5 to <1
0.25 to <0.5
STANDARD TOLERANCE (%)
±0.01%
±0.02%
±0.05%
±0.10%
±0.25%
±0.50%
Document No.: 63240
Revision: 13-Jun-2013
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1.00 (25.4)
MINIMUM
0.040 (1.0)
NOMINAL
I
1
E
1
E
2
I
2
VCS331Z, VCS332Z, VFP4Z, CSNG
Vishay Foil Resistors
TABLE 2 – SPECIFICATIONS
TEST OR CONDITION
Power Coefficient of Resistance (PCR)
Temperature Coefficient of Resistance (TCR)
(–55°C to +125°C, +25°C Reference)
Thermal Resistance
VFP4Z
Power Rating at +25°C
VCS331Z, VCS332Z
Notes
(1) Mounted on a cooled heat sink held at +25°C
(2) Heatsink—aluminum (6” L x 4” W x 2” H x 0.04” THK)
(3) Whichever is lower
PERFORMANCE
4 ppm/W maximum
(1)
≥1.0Ω to 500Ω, ±0.2 ±1.8 ppm/°C maximum
0.25Ω to <1.0Ω, ±0.2 ±2.8 ppm/°C maximum
6 °C/W
(1)
10W or 3A maximum (heatsink)
(2)(3)
3W or 3A maximum (free air)
(3)
10W or 5A maximum (heatsink)
(2)(3)
3W or 5A maximum (free air)
(3)
TABLE 3 – ENVIRONMENTAL PERFORMANCE
(1)
(PER MIL-PRF-39009)
TEST OR CONDITION
Thermal Shock
Short Time Overload (5 x rated power for 5s)
Terminal Strength
High Temperature Exposure (2000h at +150°C)
Moisture Resistance
Low Temperature Storage (24h at –55°C)
Shock (specified pulse)
Vibration (high frequency)
Load Life (rated power, +25°C, 2000h)
Thermal EMF
VFP4Z
VCS331Z, VCS332Z
Note
(1) ΔR’s plus additional 0.0005Ω for measurement error
TYPICAL ΔR LIMITS
0.01%
0.01%
0.02%
0.02%
0.03%
0.005%
0.01%
0.01%
0.01%
MAXIMUM ΔR LIMITS
0.02%
0.02%
0.05%
0.05%
0.05%
0.01%
0.02%
0.02%
0.02%
0.5 μV/°C maximum (lead effect)
4.0 μV/W maximum (power effect)
0.2 μV/°C max. (E terminal)
FIGURE 8 – LOAD LIFE TEST (VFP4Z)
Average of n=5 resistors for 3W test and n=10 resistors for 10W test
200
150
100
VFP4Z- Load Life Test for 2000 Hr
@ 3W (free air) and 10W (on heat sink
1
), +25°C
∆R (ppm)
50
0
–50
0
200 400 600 800 1000 1200 1400 1600 1800 2000
250 mΩ, 3W
250 mΩ, 10W
500 mΩ, 3W
500 mΩ, 10W
–100
–150
–200
Time (hrs)
(1) Heatsink—aluminum (6" L x 4" W x 2" H x 0.04" THK)
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Document No.: 63240
Revision: 13-Jun-2013
VCS331Z, VCS332Z, VFP4Z, CSNG
Vishay Foil Resistors
FIGURE 4 – GLOBAL PART NUMBER INFORMATION
(1)
NEW GLOBAL PART NUMBER: Y1468400R000T9L (preferred part number format)
DENOTES PRECISION
Y
VALUE
R
=
CHARACTERISTICS
0
= standard
9
= lead (Pb)-free
1 to 999
= custom
Y
1
4
6
8
4
0
0
R
0
0
0
T
9
L
1468
= VFP4Z
1481
= VCS331Z
1467
= VCS332Z
PRODUCT CODE
RESISTANCE TOLERANCE
T
= ±0.01%
Q
= ±0.02%
A
= ±0.05%
B
= ±0.1%
C
= ±0.25%
D
= ±0.5%
L
= bulk pack
PACKAGING
FOR EXAMPLE: ABOVE GLOBAL ORDER Y1468 400R000 T 9 L:
TYPE: VFP4Z
VALUE: 400Ω
ABSOLUTE TOLERANCE: ±0.01%
TERMINATION: lead (Pb)-free
PACKAGING: bulk
HISTORICAL PART NUMBER: VFP4Z 400R T B (will continue to be used)
VFP4Z
MODEL
VFP4Z
VCS331Z
VCS332Z
T
TERMINATION
T
= lead (Pb)-free
None = tin/lead alloy
400R
RESISTANCE VALUE
400Ω
T
TOLERANCE
T
= ±0.01%
Q
= ±0.02%
A
= ±0.05%
B
= ±0.1%
C
= ±0.25%
D
= ±0.5%
B
PACKAGING
B
= bulk pack
Note
(1) For non-standard requests, please contact application engineering
CSNG—NEW GENERATION OF
POWER CURRENT SENSE RESISTORS
Custom Tailored Design and Construction
The most precise measuring of electrical current is
achieved by the current sensing resistor method. The
precision and speed of response to changing current
depend on thermal stability of the resistor, as determined
by its low temperature coefficient of resistance (TCR) and
related power coefficient of resistance (PCR), as well as
its net reactance. Vishay Foil Resistors’ new-generation
Bulk Metal
®
Foil resistor technology and internal design
reduce maximum TCR to less than 0.5 ppm/°C, while a
special construction reduces thermal distortion, resulting
in a current detector with a precision of a few parts per
million (PPM) within a fraction of a second after application
of rated power.
These new resistors include multiple Bulk Metal
®
Foil
chips and are uniquely designed and tailor-made for the
customers’ specific applications.
In-Process and Post Manufacturing Operations (PMO)
tests are performed for high-end industrial, metrology, and
instrumentation applications. Prestigious scientific and
research institutes like: CERN, PTB, MEATEST, JUELICH,
DALHAUSIE University, etc., are among the users of these
CSNG.
Document No.: 63240
Revision: 13-Jun-2013
TECHNOLOGICAL BREAKTHROUGHS
• Highly efficient thermally-conductive resin to bond the
Bulk Metal
®
Foil to ceramic
• Highly efficient thermally conductive resin to bond the
chips to heat sink
• Special chip trimming method to ensure uniform heat
dissipation
• Special concept of TCR adjustment for almost zero TCR
even at low values
• Different lead diameters (cross section) for different
current specs, e.g.:
• 1 mm (18 AWG) for 15A
• 1.3 mm (16 AWG) for 20A
FLEXIBILITY OF CONSTRUCTION
TAILORED PER CUSTOMER’S SPEC
• Size and type of heat sink: with or without mounting
holes
• Size of resistor
• Mounting method with screws or bonded with thermo
conductive epoxy and clamps
• Wide range of resistive elements may be used to adapt
the resistor to customer specification
• Terminations: lead (Pb)-free or tin/lead
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