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FRST Series (Z1 Foil Technology) (0603, 0805, 1206, 1506, 2010, 2512)
For any questions, contact
foil@vpgsensors.com
Document No.: 63235
Revision: 13-Mar-2017
FRST Series (Z1 Foil Technology)
(0603, 0805, 1206, 1506, 2010, 2512)
HIGH TEMPERATURE PRODUCTS
Resistors are the passive building blocks of an electrical
circuit. They may be used for dropping the voltage,
buffering the surge when the circuit is turned on,
providing feedback in a monitoring loop, sensing current
flow, etc. When the application requires stability over
time and load, initial accuracy, minimal change with
temperature for more than 200°C, resistance to moisture
and a number of other characteristics that will be
described below, the Z1 Foil Technology products have
the attributes needed for such application. Over the past
few months, there has been considerable growth in the
demand for precise, stable and reliable resistors that can
operate in harsh environments such as 85°C/85% RH and
especially at high temperatures to 200°C. Many analog
circuits for industrial, military, aerospace, medical, down-
hole, oil well and automotive applications require passive
components such as resistors to have a minimal drift
from their initial values when operating above +175°C and
in humid environments. In these applications, the most
important factor is the temperature dependence and the
end of life tolerance (which is part of the stability) and to a
lesser extent, the initial tolerance.
The Z1 Foil Technology resistors provide stabilities
well under the maximum allowable drift required by
customers’ specifications through thousands of hours of
operation under harsh conditions, such as the extreme
temperatures and radiation-rich environments of down-
hole oil-well logging applications, in the frigid arctic, under
the sea or in deep space. All Bulk Metal Foil resistors
receive stabilization processing, such as repetitive
short term power overloads, to assure reliable service
through the unpredictable stresses of extreme operation.
Compared to Bulk Metal Foil, thick and thin film resistor
elements are produced with a non-controllable material.
Heat or mechanical stresses on the resistive elements
cause the particles forming the film to expand. However,
after these stresses are alleviated, the articles in the film
matrix do not return to the exact original position. That
degenerates their overall stability.
VPG's ultra high precision Bulk Metal Foil technology
includes many types of resistors with a variety of standard
configurations that can withstand unconventional
environmental conditions above and below the earth’s
surface using special post manufacturing operations
specially developed for this purpose. The stability of a
resistor depends primarily on its history of exposures to
high 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 of resistance, 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 that need to operate in
an environment with temperatures above +175°C, these
effects must be taken into account to achieve high
stability with changes in load (Joule Effect) and ambient
temperature.
The Z1 Foil Technology provides an order of magnitude
reduction in the Bulk Metal Foil element’s sensitivity to
temperature changes—both external and internal—with
emphasis on long-term stability in high temperature
environments.
In order to take full advantage of the low TCR and long-
term stability improvement, it is necessary to take into
account the differences in the resistor’s response to each
of the above-mentioned effects. As described below, new
products have been developed to successfully deal with
these factors. For high temperature applications where
stability and total error budget is the main concern, the
new generation of Vishay Foil resistors offers the best
resilience against time at elevated temperature.
The Z1 Foil Technology allows us to produce customer-
oriented products designed to satisfy unique and specific
technical requirements. In addition to the special chip
stabilization under extreme environment conditions in the
production line, we offer additional specially oriented post
manufacturing operations (PMO) for high temperature
applications that require an even higher degree of
reliability and stability.
Electrostatic discharge (ESD) is another potential problem
that can cause unpredictable failure in high temperature
applications that increase the sensitivity of the resistors to
ESD.
ESD damage to electronic devices can occur at any
point in the device’s life cycle, from manufacturing to
field service. A resistor that is exposed to an ESD event
may fail immediately or may experience a latent defect.
With latent defects, premature failure can occur after
the resistor is already functioning in the finished product
after an unpredictable length of service. Bulk Metal
Foil resistors are capable of withstanding electrostatic
discharges at least to 25 kV without degradation.
The VFR Application Engineering department is always
available to assist with any special requirements you
might have. If you are not sure which resistor best suits
your needs, please do not hesitate to contact them for
more information: foil@vpgsensors.com