FRSM Series of Precision Chip Resistors
Z1 Foil Ultra High Precision Wrap-around Chip Resistor for Improved
Load Life Stability of 0.0025% (25 ppm) with TCR of
± 0.05 ppm/°C and withstands ESD of 25 KV min
FEATURES
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.)
Resistance tolerance: to ± 0.01 %
Power coefficient “R due to self heating”:
5 ppm at rated power
Power rating: to 750 mW at + 70 °C
Load life stability:
± 0.0025 % at 70 °C, 2000 h at rated power.
± 0.005 % at 70 °C, 10,000 h at rated power.
Resistance Range: 5
to 125 k (for higher and lower
values, please contact us)
Vishay Foil resistors are not restricted to standard values;
we can supply specific “as required” values 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 25kV
Short time overload: 0.005 %
Rise time: 1 ns effectively no ringing
Current noise: 0.010 µV
RMS
/V of applied voltage
(< - 40 dB)
Voltage coefficient: 0.1 ppm/V
Non inductive: 0.08 µH
Non hot spot design
Terminal finishes available: lead (Pb)-free, tin/lead alloy
(1)
Matched sets are available on request
Prototype quantities available in just 5 working days
or sooner. For more information, please contact
foil@vpgsensors.com
For higher temperature application up to +240 °C and for
better performances, please contact us
Top View
INTRODUCTION
The FRSM is based on the new generation Z1-technology of
the Bulk Metal® Precision Foil resistor elements by Vishay
Precision Group (VPG), which makes these resistors
virtually insensitive to destabilizing factors. Their element,
based on the new Z1 Foil is a solid alloy that displays the
desirable bulk properties of its parent material; thus, it is
inherently stable (remarkably improved load life stability of
25 ppm), noise-free and withstands ESD to 25KV or more.
The alloy is matched to the substrate and forms a single
entity with balanced temperature characteristics for an
unusually low and predictable TCR over a wide range from
-55 C° to more than 175C°. Resistance patterns are
photo-etched to permit trimming of resistance values to very
tight tolerances.
Our application engineering department is available to
advise and make recommendations. For non-standard
technical requirements and special applications, please
contact us using the e-mail address in the footer below.
FIGURE 1 - POWER DERATING CURVE
- 55 °C
+ 70 °C
Rated Power (%)
100
75
50
25
0
- 75
TABLE 1 - TOLERANCE AND TCR VS.
RESISTANCE VALUE
(1)
(- 55 °C to + 125 °C, + 25 °C Ref.)
RESISTANCE
VALUE
()
250to 125K
100to < 250
50to < 100
25to < 50
10to < 25
5to < 10
TOLERANCE
(%)
± 0.01
± 0.02
± 0.05
± 0.1
± 0.25
± 0.5
TYPICAL TCR AND
MAX. SPREAD
(ppm/°C)
± 0.2 ± 1.8
± 0.2 ± 1.8
± 0.2 ± 2.8
± 0.2 ± 3.8
± 0.2 ± 3.8
± 0.2 ± 7.8
- 50
- 25
0
+ 25 + 50 + 75 + 100 + 125 + 150 + 175
Ambient Temperature (°C)
Lead (Pb)-free terminals
Tin/lead alloy terminals
(1)
Pb containing terminations are not RoHS compliant, exemptions may apply.
Document Number: 63209
Revision: 9-Mar-15
For any questions, contact
foil@vpgsensors.com
www.vishayfoilresistors.com
1
FRSM Series of Precision Chip Resistors
ABOUT THE FRSM
Several factors need to be considered when choosing a resistor for
applications that require long term stability, including TCR (ambient
temperature), Power TCR (self heating), load-life stability for more
than 10K hours (instead of the typical 1000 or 2000 hours load-life),
end-of-life tolerance (which is more important than the initial
tolerance), thermal EMF (low values, D.C), thermal stabilization and
ESD. Some precision resistor technologies such as Precision Thin
Film offer designers tight initial tolerances as low as 0.02 % but have
poor load life stability, high end-of-life tolerance, long thermal
stabilization, high drifts during operational life and ESD sensitivity.
Other resistor technologies, such as Wirewounds, provide low
absolute TCR and excellent current noise of -40 dB but have high
inductance and poor rise time (or thermal lag) for more than a few
seconds.
There are essentially only three resistance technologies widely used
for precision resistors in military and space applications: Thin Film,
Wirewound and Bulk Metal® Foil. Each has its own balance of
characteristics and costs that justify its selection in these
applications. Thin Films are most cost-efficient within their normal
range of characteristics but have the highest TCR, highest noise and
have the least stability of the three technologies. Wirewounds have
low noise, low TCR and a high level of stability at moderate cost but
also have high impedance and slow signal response. Wirewounds
can also have a higher power density, but some stability is lost
through temperature cycling and load-life when made in smaller
configurations. Bulk Metal® Foil resistors have the lowest noise,
lowest TCR, highest stability and highest speed of any technology
but may have a higher cost, depending upon model. With Bulk
Metal® Foil resistors, savvy designers often save overall by
concentrating the circuit stability in the foil resistors where
exceptional stability allows for use of less-costly active devices---an
option not available with other resistor technologies because foil
requires a smaller total error budget through all cumulative resistor
life exposures. Also, foil often eliminates extra circuitry added
merely for the purpose of correcting the limitations of other resistor
components. FRSM’s Bulk Metal® Foil resistors, based on new
generation technology and improved production methods starting
from February 2011, offer designers the complete set of top
performance characteristics to simplify circuitry and lower overall
system costs by reducing the number of required parts while
assuring a better end product. The new series of FRSM feature a
long-term load-life stability within 0.0025 % after 2000 hours and
0.005% after 10000 hours under full rated power at + 70 °C, first time
in the history of all resistor technologies. In addition to their low
absolute TCR of almost zero TCR , the devices offer Power TCR
(“
R due to self heating”) to ±5 ppm at rated power; tight tolerance
from 0.01% and thermal EMF of 0.05 µV/°C. Current design practice
has been to over specify resistors to allow for expected tolerance
degradation during service and there is a trend to move to
commercial off the shelf (COTS) parts instead of MIL spec Qualified
(QPL) parts. Vishay Precision Group offers a new approach with
lower prices to bring Foil resistors within the reach of designers
whose end-of-life tolerance target is 0.05 % (total end of life
cumulative deviation from nominal) or less with COTS resistors
having all the inherent features for long term reliability.
While other resistor technologies can take several seconds or even
minutes to achieve a steady state thermal stabilization (thermal lag),
Vishay Foil resistors feature an almost instantaneous thermal
stabilization time and a nearly immeasurable 1 ns rise time
effectively with no ringing. The stress levels of each application are
different so the designer must make an estimation of what they might
be and assign a stress factor to each one. The stress may normally
be low but for these purposes, we must assure that the installed
precision resistor is capable of reliability withstanding all potential
stresses. For example, if the resistor is installed in a piece of
equipment that is expected to go out into an oil field in the back of a
pickup truck, shock and vibration and heat from the sun are obvious
factors. The specific causes of resistor drift are listed in Table 4 and
the allowances shown are for full scale exposure. The designer may
choose to use a percentage of full scale stress factor if the
equipment will never see the full scale conditions. For example, a
laboratory instrument that is expected to be permanently installed in
an air-conditioned laboratory does not need an end-of-life allowance
for excessive heat. There are other reasons for tolerancing the
resistors tighter than the initial calculation: Measurement equipment
accuracy is traditionally ten times better than the expected accuracy
of the devices under test. So, these tighter tolerance applications
require a Foil resistor. Also, the drift of the resistor without any
stress factor considerations results in a shift over time that must be
considered. FRSMs have the least amount of time shift. The
manufacturer’s recommended recalibration cycle is a factor in the
saleability of the product and the longer the cycle, the more
acceptable the product. Foil resistors contribute significantly to the
longer calibration cycle.
FIGURE 2 - TRIMMING TO VALUES*
(Conceptual Illustration)
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
Mutual Inductance
Reduction due
to Change in
Current Direction
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 eliminates “hot spot” and improves the long term stability of
the resistor.
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2
For any questions, contact
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Document Number: 63209
Revision: 9-Mar-15
FRSM Series of Precision Chip Resistors
FIGURE 3 - TYPICAL RESISTANCE/
TEMPERATURE CURVE
(2)
+250
+200
+150
+100
0
R
(ppm)
-50
-100
-150
-200
-250
-55
- 0.16 ppm/ºC
-25
0
+25
+50
0.05 ppm/ºC
- 0.1 ppm/ºC
0.1 ppm/ºC
0.14 ppm/ºC
0.2 ppm/ºC
+65
+75
+100
+125
+250
+200
+150
+100
+50
0
-50
-100
-150
-200
-250
TABLE 3 - SPECIFICATIONS
(1)
CHIP
SIZE
0402
(3)
0603
0805
1206
1506
2010
2512
RATED
POWER
(mW)
at + 70 °C
50
100
200
300
300
500
750
MAX.
WORKING
VOLTAGE
(
P
R
)
5V
22 V
40 V
87 V
95 V
187 V
220 V
RESISTANCE
RANGE
()
100 to 500
100 to 4K*
5to 8K
5to 25K
5to 30K
5to 70K
5to 125K
MAXIMUM
WEIGHT
(mg)
2
4
6
11
12
27
40
Δ
R
* For 0603 values between 4K and 5K, please contact us
TABLE 2 - DIMENSIONS
in Inches (Millimeters)
Top View
L
T
D
CHIP
SIZE
0603
0805
1206
1506
2010
2512
(1)
W
L
± 0.005 (0.13)
0.063 (1.60)
0.080 (2.03)
0.126 (3.20)
0.150 (3.81)
0.198 (5.03)
0.249 (6.32)
W
± 0.005 (0.13)
0.032 (0.81)
0.050 (1.27)
0.062 (1.57)
0.062 (1.57)
0.097 (2.46)
0.127 (3.23)
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)
D
± 0.005 (0.13)
0.011 (0.28)
0.015 (0.38)
0.020 (0.51)
0.020 (0.51)
0.025 (0.64)
0.032 (0.81)
Notes
For tighter performances and non-standard values up to 150K, please contact VPG application engineering using the e-mail addresses in the
footer below.
(2)
The TCR values for < 100
are influenced by the termination composition and result in deviation from this curve.
TABLE 4 - PERFORMANCES
TEST OR CONDITIONS
Thermal Shock, 100 x (- 65 °C to + 150 °C)
(see Figure 6)
Low Temperature Operation, - 65 °C, 45 min at P
nom
Short Time Overload, 6.25 x Rated Power, 5 s
High Temperature Exposure, + 150 °C, 100 h
Resistance to Soldering Heat, +245°C for 5 sec,+235°C
for 30 sec
Moisture Resistance
Load Life Stability + 70 °C for 2000 h at Rated Power
(see Figure 8)
Load Life Stability + 70 °C for 10,000 h at Rated Power
Note
(3)
As shown + 0.01
to allow for measurement errors at low values.
R
LIMITS OF
PRECISION THIN FILM
± 0.1 %
± 0.1 %
± 0.1 %
± 0.1 %
± 0.1 %
± 0.1 %
± 0.1 %
± 0.5 %
TYPICAL
MAXIMUM
R
LIMITS OF FRSM
R
LIMITS OF FRSM
SERIES
SERIES
(3)
± 0.005% (50 ppm)
± 0.0025% (25 ppm)
± 0.005% (50 ppm)
± 0.0025% (25 ppm)
± 0.005 % (50 ppm)
± 0.003% (30 ppm)
0.0025% (25 ppm)
0.005% (50 ppm)
± 0.01% (100 ppm)
± 0.005% (50 ppm)
± 0.01% (100 ppm)
± 0.005% (50 ppm)
± 0.01% (100 ppm)
± 0.01% (100 ppm)
± 0.005% (50ppm)
± 0.015% (150ppm)
Document Number: 63209
Revision: 9-Mar-15
For any questions, contact
foil@vpgsensors.com
www.vishayfoilresistors.com
3
FRSM Series of Precision Chip Resistors
FIGURE 4 - RECOMMENDED MOUNTING
Notes
(1)
IR and vapor phase reflow are recommended.
(2)
Avoid the use of cleaning agents which could attack epoxy resins, which form part
of the resistor construction
(3)
Vacuum pick up is recommended for handling
(4)
If the use of a soldering iron becomes necessary, precautionary measures should
be taken to avoid any possible damage / overheating of the resistor
* Recommendation: The solder fillet profile should be such as to avoid running over
the top metallization
*
PULSE TEST
TEST DESCRIPTION
All parts baked at +125°C for 1 hr and allowed to cool at room
temperature for 1 hr, prior to testing. By using an electrolytic 0.01µF
capacitor charged to 1000 VDC, a single pulse was performed on 20
units of 1206, for each value: 100, 1K and 10K 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
FIGURE 6 - THERMAL SHOCK TEST
Test per MIL PRF 55342 4.8.3 Mil STD 202, Method 107
Test Conditions: 100 X (-65°C to +150°C), n=10
100
80
60
∆R
(ppm)
40
20
FIGURE 5 - PULSE TEST DESCRIPTION
0
0805
1K
0805
8K
1206
1K
1206
25K
2512
1K
-20
2512
75K
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.
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, since
damage may have occurred under the external coating.
TABLE 5 - PULSE TEST RESULTS
AVERAGE DEVIATION
(%)
VALUE
VOLTAGE
T= RC
VISHAY
FOIL
RESISTOR
<0.001
THIN
FILM
Open
>35
>0.008
100R
1K
10K
1000VDC
1µsec
10 µsec
100 µsec
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4
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Document Number: 63209
Revision: 9-Mar-15
FRSM Series of Precision Chip Resistors
TEST DESCRIPTION
By using a electrolytic 500 pF capacitor charged up to 4500 V,
pulses were performed on 10 units of 1206, 10K of three different
Surface Mount Chip Resistors technologies, with an initial voltage
spike of 2500 V (Figure 7). 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
POWER COEFFICIENT OF RESISTANCE
(PCR)
In precision resistors with low TCR, the self heating (Joule effect)
causes the resistor not to perform strictly to its TCR specifications.
This inaccuracy will result in an error at the end in the resistance
value under applied power. Vishay Foil Resistors introduced a new
concept of Power Coefficient of Resistance (PCR) along with a new
Z-Foil technology which leads to reduction of the sensitivity of
precision resistor to ambient temperature variations and changes of
applied power.
Figure 9 represents PCR behavior of three different resistor
technologies under applied power.
FIGURE 7 - ESD TEST DESCRIPTION
2500 V to 4500 V
1 MΩ
500 pF
FIGURE 9 - BEHAVIOR OF THREE
DIFFERENT RESISTOR
TECHNOLOGIES UNDER
APPLIED POWER (POWER
COEFFICIENT TEST)
0.1
0.2
Thick Film
Surface
Mount Chip
0.3
0.4
Thin Film
Surface
Mount Chip
0.5
Rx
+ 100 ppm
DMM
ΔR
(ppm)
-------
-
R
0 ppm
Z-Foil
Surface
Mount Chip
TABLE 6 - ESD TEST RESULTS
VOLTS
2500
3000
3500
4000
4500
∆R
(%)
THICK FILM
-2.7
-4.2
-6.2
-7.4
-8.6
THIN FILM
97
366
>5000
>5000
OPEN
FOIL
<0.005
<0.005
<0.005
<0.005
<0.005
Note: Size 1206, value: 1K
- 100 ppm
Applied power, (W)
FIGURE 10 - CURRENT PATH IN A
RESISTIVE ALLOY
FIGURE 8 - LOAD LIFE TEST FOR
2000 HRS @ +70°C
AT RATED POWER
100
80
60
40
20
0
-20 0
-40
-60
-80
-100
250
500
750
1000 1250 1500 1750 2000 2250
0805-1K
0805-8K
1206-1K
1206-25K
2512-75K
2512-125K
∆R (ppm)
Noise generation is minimal when current
flow is through multiple paths as exists in
Bulk Metal
®
Foil resistive alloy.
Time (hrs)
Document Number: 63209
Revision: 9-Mar-15
For any questions, contact
foil@vpgsensors.com
www.vishayfoilresistors.com
5
