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
• Temperature coefficient of resistance (TCR):
NEW
- ± 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
INTRODUCTION
±0.015% at 70°C,10000 h (see table 4)
The Bulk Metal® Foil resistor is based on a special concept
• Resistance range: 10 Ω to 600 kΩ
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.
• 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 µVRMS/V of applied voltage (< - 40 dB)
• Thermal EMF: 0.05 µV/°C typical
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)
• Voltage coefficient: < 0.1 ppm/V
• Low inductance: < 0.08 µH typical
2. Destabilizing thermal shock of suddenly-applied power
(defined by the power coefficient, or PCR)
• Thermal stabilization time < 1 s (nominal value achieved
within 10 ppm of steady state value)
3. Long-term exposure to applied power (load-life stability)
4. Repetitive stresses from being switched on and off
• Pattern design minimizing hot spots
• Terminal finish: lead (Pb)-free or tin/lead alloy
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.
• 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
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.
• Load life ΔR maximum can be reduced significantly
with our post manufacturing operations (PMO) see
page 4 for details
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.
FIGURE 1 - TYPICAL RESISTANCE/
TEMPERATURE CURVE (Z-FOIL)
+ 500
+ 400
+ 300
+ 200
TABLE 1 - TYPICAL TCR AND MAX. SPREAD
+ 100
ΔR
(- 55 °C to + 125 °C, + 25 °C ref.)
0
- 100
- 200
- 300
- 400
- 500
R
(ppm)
TYPICAL TCR AND
MAX. SPREAD
(ppm/°C)
0.05 ppm/°C
- 0.1 ppm/°C 0.1 ppm/°C
0.14 ppm/°C
STANDARD
TOLERANCE
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
± 0.005 %
± 0.005 %
± 0.01 %
± 0.01 %
± 0.02 %
± 0.2 ± 0.6
± 0.2 ± 0.8
± 0.2 ± 1.0
± 0.2 ± 1.3
± 0.2 ± 1.6
- 0.16 ppm/°C
0.2 ppm/°C
- 55
- 25
0
+ 25
+ 60 + 75 + 100 + 125
Ambient Temperature (°C) and TCR Chord Slopes
for Different Temperature Ranges
* 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
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