Z Series (Z-Foil)
Vishay Foil Resistors
Ultra High Precision Z-Foil Resistor with TCR of ± 0.05 ppm/°C,
Tolerance of ± 0.005 % (50 ppm), Load Life Stability of ± 0.005 %,
ESD Immunity up to 25 kV and Thermal EMF of 0.05 µV/°C
FEATURES
NEW
INTRODUCTION
The Bulk Metal
®
Foil resistor is based on a special concept
where a proprietary bulk metal cold rolled foil is cemented to
a ceramic substrate. It is then photoetched into a resistive
pattern. Furthermore, it is laser adjusted to any desired value
and tolerance. Because the metals used are not drawn,
wound or mistreated in any way during manufacturing
process, the Bulk Metal Foil resistor maintains all its design,
physical and electrical characteristics while winding of wire
or sputtering does not. Z foil resistors achieve maximum
stability and near-zero TCR. These performance
characteristics are built-in for every unit, and do not rely on
screening or other artificial means for uniform performances.
The stability of a resistor depends primarily on its history of
exposures to temperature. Stability is affected by:
1. Changes in the ambient temperature and heat from
adjacent components (defined by the Temperature
Coefficient of Resistance, or TCR)
2. Destabilizing thermal shock of suddenly-applied power
(defined by the power coefficient, or PCR)
3. Long-term exposure to applied power (load-life stability)
4. Repetitive stresses from being switched on and off
In very high-precision resistors, these effects must be taken
into account to achieve high stability with changes in load
(Joule Effect) and ambient temperature.
Vishay’s new Z-Foil technology provides an order of
magnitude reduction in the Bulk Metal Foil element’s
sensitivity to temperature changes - both external and
internal. This technology provides an absolute TCR of
± 0.05 ppm/°C typical (instrument range: 0 °C to +60 °C),
± 0.2 ppm/°C typical (military range: - 55 °C to + 125 °C,
+ 25 °C ref), and a PCR of 5 ppm at rated power.
In order to take full advantage of this TCR improvement, it is
necessary to take into account the differences in the
resistor’s response to each of the above-mentioned effects.
The Z series has been developed to successfully deal with
these factors.
•
Temperature coefficient of resistance (TCR):
- ± 0.05 ppm/°C typical (0 °C to + 60 °C)
- ± 0.2 ppm/°C typical (- 55 °C to + 125 °C,
+ 25 °C ref.) (see table 1)
•
Rated power: to 1 W at + 125 °C
•
Resistance tolerance: to ± 0.005 % (50 ppm)
•
Load life stability: to ± 0.005 % at 70 °C, 2000 h or to
±0.015% at 70°C,10000 h (see table 4)
•
Resistance range: 10
Ω
to 600 kΩ
•
Vishay Foil Resistors are not restricted to standard values;
specific “as required” values can be supplied at no extra
cost or delivery (e.g. 1K2345 vs. 1K)
•
Total accumulated change in resistance over life (EOL)
< 0.05 % (or better with PMO)
•
Electrostatic discharge up to 25 000 V
•
Non-inductive, non-capacitive design
•
Rise time: 1 ns effectively no ringing
•
Current noise: 0.010 µV
RMS
/V of applied voltage (< - 40 dB)
•
Thermal EMF: 0.05 µV/°C typical
•
Voltage coefficient: < 0.1 ppm/V
•
Low inductance: < 0.08 µH typical
•
Thermal stabilization time < 1 s (nominal value achieved
within 10 ppm of steady state value)
•
Pattern design minimizing hot spots
•
Terminal finish: lead (Pb)-free or tin/lead alloy
•
Matched sets are available per request
(TCR tracking: to 0.5 ppm/°C)
•
Prototype quantities available in just 5 working days
or sooner. For more information, please contact
foil@vishaypg.com
•
Load life
ΔR
maximum can be reduced significantly
with our post manufacturing operations (PMO) see
page 4 for details
FIGURE 1 - TYPICAL RESISTANCE/
TEMPERATURE CURVE (Z-FOIL)
+ 500
+ 400
+ 300
+ 200
+ 100
ΔR
0
R
(ppm)
- 100
- 200
- 300
- 400
- 500
- 55
- 25
+ 25
+ 60 + 75 + 100 + 125
0
Ambient Temperature (°C) and TCR Chord Slopes
for Different Temperature Ranges
- 0.16 ppm/°C
TABLE 1 - TYPICAL TCR AND MAX. SPREAD
(- 55 °C to + 125 °C, + 25 °C ref.)
VALUE
100
Ω
to 600 KΩ
80
Ω
to < 100
Ω
50
Ω
to < 80
Ω
25
Ω
to < 50
Ω
10
Ω
to < 25
Ω
STANDARD
TOLERANCE
± 0.005 %
± 0.005 %
± 0.01 %
± 0.01 %
± 0.02 %
TYPICAL TCR AND
MAX. SPREAD
(ppm/°C)
± 0.2 ± 0.6
± 0.2 ± 0.8
± 0.2 ± 1.0
± 0.2 ± 1.3
± 0.2 ± 1.6
0.05 ppm/°C
- 0.1 ppm/°C
0.1 ppm/°C
0.14 ppm/°C
0.2 ppm/°C
* Pb containing terminations are not RoHS compliant, exemptions may apply
Document Number: 63187
Revision: 21-Jul-10
For any questions, contact:
foil@vishaypg.com
www.foilresistors.com
1
Z Series (Z-Foil)
Vishay Foil Resistors
FIGURE 3 - POWER DERATING CURVE
100
- 55 °C
+ 70 °C
Rated Power
FIGURE 4 - TRIMMING TO VALUES
(conceptual illustration)
Rated Power (%) at + 70 °
75
Interloop Capacitance
Reduction in Series
Current Path
Before Trimming
Current Path
After Trimming
Trimming Process
Removes this Material
from Shorting Strip Area
Changing Current Path
and Increasing
Resistance
50
Recommended
operation for
< 150 ppm
ΔR
after 2000 h
load life
25
Mutual Inductance
Reduction due
to Change in
Current Direction
0
- 75 - 50 - 25
0
+ 25 + 50 + 75 + 100 + 125 + 150 + 175 + 200
Ambient Temperature (°C)
Note:
Foil shown in black, etched spaces in white
TABLE 3 - ENVIRONMENTAL PERFORMANCE COMPARISON
MIL-PRF-55182
CHAR J
Test Group I
Thermal shock, 5 x (- 65 °C to + 150 °C)
Short time overload, 6.25 x rated power
Test Group II
Resistance temperature characteristics
Low temperature storage (24 h at - 65 °C)
Low temperature operation
(45 min, rated power at - 65 °C)
Terminal strength
Test Group III
DWV
Resistance to solder heat
Moisture resistance
Test Group IV
Shock
Vibration
Test Group V
Life test at 0.3 W/+ 125 °C
2000 h
10 000 h
Test Group Va
Life test at 0.6 W (2 x rated power)/+ 70 °C, 2000 h
Test Group VI
High temperature exposure (2000 h at + 175 °C)
Test Group VII
Voltage coefficient
5 ppm/V
< 0.1 ppm/V
< 0.1 ppm/V
± 2.0 %
± 0.05 % (500 ppm)
± 0.1 % (1000 ppm)
± 0.5 %
± 0.005 % (50 ppm)
± 0.015 % (150 ppm)
± 0.5 %
± 2.0 %
± 0.005 % (50 ppm)
± 0.015 % (150 ppm)
± 0.015 % (150 ppm)
± 0.05 % (500 ppm)
± 0.2 %
± 0.2 %
± 0.002 % (20 ppm)
± 0.002 % (20 ppm)
± 0.01 % (100 ppm)
± 0.01 % (100 ppm)
± 0.15 %
± 0.1 %
± 0.4 %
± 0.002 % (20 ppm)
± 0.005 % (50 ppm)
± 0.01 % (100 ppm)
± 0.01 % (100 ppm)
± 0.01 % (100 ppm)
± 0.05 % (500 ppm)
± 25 ppm/°C
± 0.15 %
± 0.15 %
± 0.2 %
± 0.05 ppm/°C
± 0.002 % (20 ppm)
± 0.002 % (20 ppm)
± 0.002 % (20 ppm)
see table 1
± 0.01 % (100 ppm)
± 0.01 % (100 ppm)
± 0.01 % (100 ppm)
± 0.2 %
± 0.2 %
± 0.002 % (20 ppm)
± 0.003 % (30 ppm)
± 0.01 % (100 ppm)
± 0.01 % (100 ppm)
Z SERIES
TYPICAL
ΔR
Z SERIES
MAXIMUM
ΔR
Document Number: 63187
Revision: 21-Jul-10
For any questions, contact:
foil@vishaypg.com
www.foilresistors.com
3
Z Series (Z-Foil)
Vishay Foil Resistors
STANDARD OPERATIONS AND TEST
CONDITIONS
A. Standard Test Operations:
By 100 % Inspection
•
•
Short-time overload (6.25 x rated power for 5 s)
Resistance - tolerance check
POST MANUFACTURING OPERATIONS OR
PMO
Many analog applications can include requirements for
performance under conditions of stress beyond the normal
and over extended periods of time. This calls for more than
just selecting a standard device and applying it to a circuit.
The standard device may turn out to be all that is needed but
an analysis of the projected service conditions should be
made and it may well dictate a routine of stabilization known
as post manufacturing operations or PMO. The PMO
operations that will be discussed are only applicable to Bulk
Metal Foil resistors. They stabilize Bulk Metal Foil resistors
while they are harmful to other types. Short time overload,
accelerated load life, and temperature cycling are the three
PMO exercises that do the most to remove the anomalies
down the road. Vishay Bulk Metal Foil resistors are
inherently stable as manufactured. These PMO exercises
are only of value on Bulk Metal Foil resistors and they
improve the performance by small but significant amounts.
Users are encouraged to contact Vishay Foil applications
engineering for assistance in choosing the PMO operations
that are right for their application.
•
Visual and mechanical
By Sample Inspection
•
•
TCR
Environmental tests per table 3 on a quarterly basis
to establish performance by similarity
B. Standard Test Conditions:
•
•
•
Lead test point: 0.5" (12.7 mm) from resistor body
Temperature: + 23 °C ± 2 °C
Relative humidity: per MIL-STD-202
TABLE 4 - “Z” SERIES SPECIFICATIONS
Stability
(1)
Load life at 2000 h
± 0.015 % (150 ppm)
± 0.005 % (50 ppm)
Load life at 10 000 h
± 0.05 % (500 ppm)
± 0.01 % (100 ppm)
Current Noise
High Frequency Operation
Rise time
Inductance (L)
(2)
Capacitance (C)
Voltage Coefficient
Thermal EMF
(4)
1.0 ns at 1 kΩ
0.1 µH maximum; 0.08 µH typical
1.0 pF maximum; 0.5 pF typical
< 0.1 ppm/V
(3)
0.05 µV/°C typical
1 µV/W
(1)
(2)
(3)
(4)
Maximum
ΔR
at 0.3 W/+ 125 °C
Maximum
ΔR
at 0.1 W/+ 70 °C
Maximum
ΔR
at 0.3 W/+ 125 °C
Maximum
ΔR
at 0.1 W/+ 70 °C
0.010 µVRMS/V of applied voltage (< - 40 dB)
(Model Z201)
Notes
Load life
ΔR
maximum can be reduced by 80 %, please contact applications engineering department.
Inductance (L) due mainly to the leads.
The resolution limit of existing test equipment (within the measurement capability of the equipment, or “essentially zero”.)
µV/°C relates to EMF due to lead temperature difference and µV/watt due to power applied to the resistor.
www.foilresistors.com
4
For any questions, contact:
foil@vishaypg.com
Document Number: 63187
Revision: 21-Jul-10
Power technology
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