HTHA (Z1-Foil)
Vishay Foil Resistors
Ultra High Precision Z1-Foil Technology Chip Resistor for Hybrid
Circuits with Aluminum Wire Bonding for High Temperature
Applications up to +240°C, Long Term Stability of 0.05%,
TCR to ± 1ppm/°C
FEATURES
Temperature coefficient of resistance (TCR):
±1 ppm/°C typical (- 55 °C to + 125 °C, + 25 °C ref.)
±2.5 ppm/°C typical (- 55 °C to + 220 °C, + 25 °C
ref.)
Resistance range: 5 to 125 k(for higher
or lower values, please contact VFR's application
engineering department)
Resistance tolerance: to ± 0.02 %
Connection method: aluminum wire bonding*
Working power: to 150mW at + 220°C
Long term stability: to ± 0.05 % at + 240°C for 2000h, no
power
Load life stability: to 0.05% at + 220°C for 2000h at
working power
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)
Thermal stabilization time < 1 s (nominal value achieved
within 10 ppm of steady state value)
Electrostatic discharge (ESD) at least to 25 kV
Non inductive, non capacitive design
Rise time: 1 ns effectively no ringing
Current noise: 0.010 µV (RMS)/Volt of applied voltage
(< - 40 dB)
Voltage coefficient: < 0.1 ppm/V
Non inductive: < 0.08 µH
Non hot spot design
Terminal finish available: gold plated (lead (Pb)-free alloy)
Prototype quantities available in just 5 working days
or sooner. For more information, please contact
foil@vishaypg.com
* For other mounting option: facing down (flip chip) mounted by
electrical conductive-epoxy please contact application engineering
department
INTRODUCTION
Vishay Foil Resistors (VFR) introduces a new line of Ultra
Precision Bulk Metal
®
Z1-Foil technology: chip resistor for
hybrid circuits with aluminum wire bonding. These new types
of hybrid chips were especially designed for high
temperature applications up to + 240 °C
(1)
(working power: to
150mW at + 220°C), and include gold plated terminals.
The HTHA series is available in any value within the
specified resistance range. VFR's application engineering
department is available to advise and make
recommendations.
For non-standard technical requirements and special
applications, please contact
foil@vishaypg.com.
TABLE 1 - TOLERANCE AND TCR VS.
RESISTANCE VALUE
(1)(2)
(- 55 °C to + 220 °C, + 25 °C Ref.)
RESISTANCE
VALUE
()
100to 125K
50to < 100
25to < 50
10to < 25
5to 10
TOLERANCE
(%)
± 0.02
± 0.05
± 0.1
± 0.25
± 0.5
Percent of Rated Power
Note
(1)
Performances obtained with ceramic PCB.
(2)
For tighter performances or non-standard values up to 150 k,
please contact VFR's application engineering department by
sending an e-mail to the address in the footer below.
Document Number: 63222
Revision: 20-Dec-11
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TCR Typical
(ppm/°C)
± 2.5
-55°C
+70°C
100
75
50
25
0
-75
-50
-25
0
+25
+50
FIGURE 1 - POWER DERATING CURVE
+240
+75 +100 +125 +150 +175 +200 +225 +250
Ambient Temperature (°C)
For any questions, contact:
foil@vishaypg.com
www.vishayfoilresistors.com
1
HTHA (Z1-Foil)
Vishay Foil Resistors
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, only the new
generation of Vishay Foil Resistors have the attributes
needed for this 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 and especially at high temperatures to 220 °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 end of life tolerance (which is part
of the stability) and to a lesser extent, the initial tolerance.
The new Vishay Foil 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
particles in the film matrix do not return to the exact original
position. That degenerates their overall stability.
Vishay Foil Resistors’ 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 Bulk Metal
®
Foil Resistors’ new 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 new Vishay 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.
www.vishayfoilresistors.com
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For any questions, contact:
foil@vishaypg.com
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 volts
without degradation.
VFR’s 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@vishaypg.com
Document Number: 63222
Revision: 20-Dec-11
HTHA (Z1-Foil)
Vishay Foil Resistors
TABLE 2 - PRODUCT SPECIFICATIONS
PRODUCT
HTHA
CONNECTING METHOD*
Aluminum wire bonding
SIZES
0603,0805,1206,
1506,2010,2512
TABLE 3 - SPECIFICATIONS
CHIP
SIZE
0603
0805
1206
1506
2010
2512
(1)
WORKING
POWER (mW)
at + 220 °C
(1)
12.5
20
33
40
100
150
RESISTANCE RANGE
()
100 to 5K
5to 8K
5to 25K
5to 30K
5 to 70K
5to 125K
* The HTHA series can also act as a surface mount (flip chip—facing
down) and to be mounted using electrical conductive epoxy. For
more information, please contact application engineering
department.
Note
Maximum working voltage at +220°C for a given resistance value is
calculated using
V
=
P
R
.
FIGURE 2 - TRIMMING TO VALUES
(Conceptual Illustration)
Interloop Capacitance
Reduction in Series
Mutual Inductance
Reduction due
to Change in
Current Direction
Document Number: 63222
Revision: 20-Dec-11
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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
To acquire a precision resistance value, the Bulk Metal
®
Foil
chip is trimmed by selectively removing built-in “shorting bars.”
To increase the resistance in known increments, marked areas
are cut, producing progressively smaller increases in resistance.
This method reduces the effect of “hot spots” and improves the
long term stability of the Vishay Foil chips.
For any questions, contact:
foil@vishaypg.com
www.vishayfoilresistors.com
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HTHA (Z1-Foil)
Vishay Foil Resistors
TABLE 4 - DIMENSIONS
in inches (millimeters)*
D
Gold Plated Terminals
W
W1 [W - 0.003"]
L - 0.005 (0.13)
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CHIP
SIZE
0603
0805
1206
1506
2010
2512
L
± 0.005 (0.13)
0.063 (1.60)
0.079 (2.01)
0.126 (3.20)
0.150 (3.81)
0.200 (5.08)
0.250 (6.35)
W
± 0.005 (0.13)
0.032 (0.81)
0.049 (1.24)
0.062 (1.57)
0.062 (1.57)
0.100 (2.54)
0.126 (3.20)
THICKNESS
MAXIMUM
0.025 (0.64)
0.025 (0.64)
0.025 (0.64)
0.025 (0.64)
0.025 (0.64)
0.025 (0.64)
R
LIMITS OF OF THIN FILM
(TYPICAL)
± 0.1 %
± 0.1 %
± 0.1 %
± 0.5 %
± 0.5 %
For any questions, contact:
foil@vishaypg.com
L
D
NOMINAL
0.006 (0.15)
0.010 (0.25)
0.015 (0.38)
0.012 (0.30)
0.020 (0.51)
0.024 (0.61)
* Notes
•
•
Avoid the use of cleaning agents that could attack epoxy resins, which form part of the resistor construction
Vacuum pick up is recommended for handling
TABLE 5 - COMPARATIVE PERFORMANCES
(1) -
THIN FILM VS. BULK METAL
®
Z1-FOIL
TECHNOLOGY
TEST OR CONDITIONS
R
LIMITS OF BULK METAL
®
Z1-FOIL
TECHNOLOGY - HTHA SERIES
(2)
(TYPICAL)
± 0.03% (300 ppm)
Thermal Shock, 5 x (- 65 °C to + +220 °C)
Low Temperature Operation, - 65 °C, 45 min at
Rated Power
Moisture Resistance
± 0.0025% (25 ppm)
± 0.003% (30 ppm)
± 0.05% (500 ppm)
Load Life Stability, + 220 °C for 2000 h at working
power (see table 3)
Long term stability,+ 240 °C for 2000h, no power
Note
(1)
As
(2)
± 0.05% (500 ppm)
shown + 0.01
to allow for measurement errors at low values.
Performances obtained with ceramic PCB.
www.vishayfoilresistors.com
4
Document Number: 63222
Revision: 20-Dec-11
HTHA (Z1-Foil)
Vishay Foil Resistors
PULSE TEST
TEST DESCRIPTION
All parts are baked at +125°C for 1 hour and allowed to cool at room
temperature for 1 hour, prior to testing. By using an electrolytic
0.01µF capacitor charged to 1200 VDC, a single pulse was
performed on 30 units of 1206, 10 k of Surface Mount Vishay Foil
resistor and Thin Film resistor. The unit was allowed time to cool
down, after which the resistance measurement was taken and
displayed in ppm deviation from the initial reading.
TEST RESULTS
Catastrophic Damage
- occurs when the ESD event causes the
device to immediately stop functioning. This may occur after one or
a number of ESD events with diverse causes, such as human body
discharge or the mere presence of an electrostatic field.
Latent Damage
- occurs when the ESD event causes moderate
damage to the device, which is not noticeable, as the device appears
to be functioning correctly. However, the load life of the device has
been dramatically reduced, and further degradation caused by
operating stresses may cause the device to fail during service.
Latent damage is the source for greatest concern, since it is very
difficult to detect by re-measurement or by visual inspection,
because damage may have occurred under the external coating.
TEST DESCRIPTION
By using an electrolytic 500 pF capacitor charged up to 4500 V,
pulses were performed on 10 units of 1206, 10 k of three different
Surface Mount Chip Resistors technologies, with an initial voltage
spike of 2500 V (Figure 5). The unit was allowed time to cool down,
after which the resistance measurement was taken and displayed in
ppm deviation from the initial reading. Readings were then taken in
500 V increments up to 4500 V.
TEST RESULTS
FIGURE 3 - PULSE TEST DESCRIPTION
FIGURE 4 - PULSE TEST RESULTS AT
1200 VDC*
140000
120000
100000
80000
60000
40000
20000
0
-20000
* Note: Average of 30 units yielded deviation of 30,723 ppm for the
Thin Film vs. -14 ppm for the Bulk Metal
®
Foil
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"#
*+
!)
FIGURE 5 - ESD TEST DESCRIPTION
2500 V to 4500 V
1 MΩ
500 pF
Thin Film
ΔR (ppm)
Bulk Metal
®
Foil
Rx
Size: 1206
Value: 10K
n = 30
0
5
10
15
20
25
30
Resistor #
DMM
TABLE 6 - ESD TEST RESULTS
VOLTS
2500
3000
3500
4000
4500
∆R
(%)
FOIL
<0.005
<0.005
<0.005
<0.005
<0.005
97
366
>5000
>5000
OPEN
THICK FILM
-2.7
-4.2
-6.2
-7.4
-8.6
THIN FILM
ELECTROSTATIC DISCHARGE (ESD)
ESD can be categorized into three types of damages:
Parametric Failure
- occurs when the ESD event alters one or more
device parameters (resistance in the case of resistors), causing it to
shift from its required tolerance. This failure does not directly pertain
to functionality; thus a parametric failure may be present while the
device is still functional.
Document Number: 63222
Revision: 20-Dec-11
For any questions, contact:
foil@vishaypg.com
www.vishayfoilresistors.com
5
Test/Measurement
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