Z Series (Z Foil)
Ultra High Precision Z Foil Though-Hole Resistor
with TCR of ±0.2 ppm/°C, Tolerance of ±0.005% (50 ppm),
Load Life Stability of ±0.005%
FEATURES
•
Temperature coefficient of resistance (TCR):
±0.2 ppm/°C typical (–55°C to +125°C, +25°C ref.)
(see table 1)
• Rated power: to 1 W at +125°C (see table 2)
• Resistance tolerance: to ±0.005% (50 ppm)
• Load life stability: ±0.005% at 70°C, 2000 h or
±0.015% at 70°C, 10000 h (see table 4)
• Resistance range: 5 Ω to 600 kΩ
• Bulk Metal
®
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 value over life
or Total Error Budget <0.1% (or tighter with PMO)**
• 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
/V of applied voltage
(<–40 dB)
• Thermal EMF: 0.05 μV/°C typical
• Voltage coefficient: <3 ppm/V
• Low inductance: <0.08 μH typical
• Thermal stabilization time <1 s (to reach 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)
• Military established reliability “R” level resistor available
(see resistor model RNC90Z)
• Screen/test flow as modified from S-311-P813
proposed by NASA available
(see datasheet for resistor model 303143)
• Prototype quantities available please contact
foil@vpgsensors.com
The stability of a resistor depends primarily on its history
of exposures to temperature. Stability is affected by:
1. Reversible changes in the ambient temperature
and heat from adjacent components (defined by the
Temperature Coefficient of Resistance, or TCR)
2. Short-term steady-state self-heating (defined by
Power TCR or PCR)
3. Irreversible destabilizing shock of suddenly-applied
power
4. Long-term exposure to applied power (load-life
stability)
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 Foil Resistors’ 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 TCR of ±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.
* This datasheet provides information about parts that are
RoHS-compliant and/or parts that are non-RoHS-compliant.
For example, parts with lead (Pb) terminations are not
RoHS compliant. Please see the information/tables in this
datasheet for details.
** See PMO page 5
INTRODUCTION
The Bulk Metal
®
Foil resistor is based on a special
thermo-metalic stress concept wherein a proprietary bulk
metal cold rolled foil is cemented to a ceramic substrate.
It is then photoetched into a resistive pattern. Then 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
performance.
Document No.: 63187
Revision: 01-Nov-2016
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
5 Ω to <10 Ω
STANDARD
TOLERANCE
±0.005%
±0.005%
±0.01%
±0.01%
±0.02%
±0.05%
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
±0.2 ±2.3
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Z Series (Z Foil)
FIGURE 1 – TYPICAL RESISTANCE/
TEMPERATURE CURVE
(for more details, see table 1)
+500
TCR Values for Different Temperature Ranges
FIGURE 2 – POWER DERATING CURVE
- 55 °C
+ 70 °C
Rated Power
100
+400
+300
Rated Power (%) at + 70 °
+125
75
+100
R
0
R
(ppm)
–100
–200
–300
–500
+200
50
0.05 ppm/°C
–0.1 ppm/°C
–0.16 ppm/°C
–55
–25
0.1 ppm/°C
0.14 ppm/°C
0.2 ppm/°C
+100
25
–400
0
+25
+60 +75
Ambient Temperature (°C)
0
- 75 - 50 - 25
Note
The TCR values for <100 Ω are influenced by the termination
composition and result in deviation from this curve
Ambient Temperature (°C)
0
+ 25 + 50 + 75 + 100 + 125 + 150 + 175 + 200
FIGURE 3 – TRIMMING TO VALUES
(conceptual illustration)
Interloop
Capacitance
Reduction
in Series
Mutual Inductance
Reduction due
to Change in
Current Direction
Current Path
Before Trimming
Current Path After Trimming
Trimming Process
Removes this Material
from Shorting Strip Area
Changing Current Path
and Increasing
Resistance
Note
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 Bulk Metal Foil resistors.
Foil shown in black, etched spaces in white
FIGURE 4 -THROUGH-HOLE STYLE (29 YEARS)
40
20
∆R/R (ppm)
0
-20
-40
-60
-80
-100
-120
0
5
10
15
20
25
30
Time (Years)
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Document No.: 63187
Revision: 01-Nov-2016
Z Series (Z Foil)
TABLE 2 – MODEL SELECTION
MODEL
NUMBER
RESISTANCE
RANGE
(2)
MAXIMUM
WORKING
VOLTAGE
AMBIENT POWER
RATING
at +70°C
at +125°C
AVERAGE
WEIGHT
DIMENSIONS
INCHES
W: 0.105 ±0.010
L: 0.300 ±0.010
H: 0.326 ±0.010
ST: 0.010 min.
SW: 0.040 ±0.005
LL: 1.000 ±0.125
LS: 0.150 ±0.005
(1)
W: 0.160 max.
L: 0.575 max.
H: 0.413 max.
ST: 0.035 ±0.005
SW: 0.050 ±0.005
LL: 1.000 ±0.125
LS: 0.400 ±0.020
W: 0.160 max.
L: 0.820 max.
H: 0.413 max.
ST: 0.035 ±0.005
SW: 0.050 ±0.005
LL: 1.000 ±0.125
LS: 0.650 ±0.020
W: 0.260 max.
L: 1.200 max.
H: 0.413 max.
ST: 0.035 ±0.005
SW: 0.050 ±0.005
LL: 1.000 ±0.125
LS: 0.900 ±0.020
mm
2.67 ±0.25
7.62 ±0.25
8.28 ±0.25
0.254 min.
1.02 ±0.13
25.4 ±3.18
3.81 ±0.13
4.06 max.
14.61 max.
10.49 max.
0.889 ±0.13
1.27 ±0.13
25.4 ±3.18
10.16 ±0.51
4.06 max.
20.83 max.
10.49 max.
0.889 ±0.13
1.27 ±0.13
25.4 ±3.18
16.51 ±0.51
6.60 max.
30.48 max.
10.49 max.
0.889 ±0.13
1.27 ±0.13
25.4 ±3.18
22.86 ±0.51
Z201
(Z201L)
(1)
5 Ω to 100 kΩ
300 V
0.6 W
0.3 W
0.5 g
Z204
5 Ω to 200 kΩ
350 V
1.0 W
0.5 W
1.25 g
Z205
5 Ω to 300 kΩ
350 V
1.5 W
0.75 W
1.75 g
2.0 W
Z206
5 Ω to 600 kΩ
500 V
1.0 W
3.7 g
up to 400K
1.0 W
0.5 W
over 400K
Note
(1)
0.200
in
(5.08 mm) lead spacing available – specify Z201L instead of Z201.
(2)
For non standard values please contact Application Engineering at
foil@vpgsensors.com
FIGURE 5 – STANDARD IMPRINTING AND DIMENSIONS
Front View
L
H
VFR
XXXX
Z201
Date Code
10
10
Year Week
ST
LS
1)
W
Optional Customer Part Number
Print Specification, etc., if Required
XXXXXX
100R01
0.01%
SW
Resistance
Value Code
Tolerance
LL
Rear View
Model
Number
Lead Material
#22 AWG Round
Solder Coated Copper
Note
1. The standoffs shall be so located as to give a lead clearance of 0.010 in minimum between the resistor body and the printed
circuit board when the standoffs are seated on the printed circuit board. This is to allow for proper cleaning of flux and other
contaminants from the unit after all soldering processes.
Document No.: 63187
Revision: 01-Nov-2016
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foil@vpgsensors.com
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Z Series (Z Foil)
TABLE 3 – ENVIRONMENTAL PERFORMANCE COMPARISON
MIL-PRF-55182
CHAR J
Test Group I
Thermal shock, 5
×
(–65°C to +150°C)
Short time overload, 6.25
×
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
Insulation resistance
Resistance to solder heat
Moisture resistance
Test Group IV
Shock
Vibration
Test Group V
Life test at rated power / +125°C
2 000 h
10 000 h
Test Group Va
Life test at 2
×
rated power / +70°C, 2 000 h
Test Group VI
High temperature exposure (2 000 h at +175°C)
Test Group VII
Voltage coefficient
(1)
Z SERIES
TYPICAL ∆R
±0.002% (20 ppm)
±0.003% (30 ppm)
±0.2 ppm/°C
±0.002% (20 ppm)
±0.002% (20 ppm)
±0.002% (20 ppm)
±0.002% (20 ppm)
±0.005% (50 ppm)
±0.010% (100 ppm)
±0.002% (20 ppm)
±0.002% (20 ppm)
Z SERIES
MAXIMUM ∆R
(1)
±0.01% (100 ppm)
±0.01% (100 ppm)
see table 1
±0.01% (100 ppm)
±0.01% (100 ppm)
±0.01% (100 ppm)
±0.01% (100 ppm)
≥10
4
MΩ
±0.01% (100 ppm)
±0.02% (200 ppm)
±0.01% (100 ppm)
±0.01% (100 ppm)
±0.2%
±0.2%
±25 ppm/°C
±0.15%
±0.15%
±0.20%
±0.15%
≥10
4
MΩ
±0.10%
±0.40%
±0.2%
±0.2%
±0.5%
±2.0%
±0.5%
±2.0%
5 ppm/V
±0.005% (50 ppm)
±0.015% (150 ppm)
±0.005% (50 ppm)
±0.02% (200 ppm)
±0.015% (150 ppm)
±0.050% (500 ppm)
±0.015% (150 ppm)
±0.05% (500 ppm)
3 ppm/V
Measurement error allowed for ∆R limits: 0.01 Ω
STANDARD OPERATIONS AND
TEST CONDITIONS
A. Standard Test Operations
By 100% Inspection:
•
•
•
•
TCR
Short-time overload (6.25
×
rated power for 5 s)
Resistance – tolerance check
Visual and mechanical
LONG-TERM STABILITY
Some process controls are not very critical but many,
many are – particularly when a process is operating near
a tipping point where it could get out of control quickly if
not well monitored.
In process control applications, entire production batches
have been lost or suffered reduced reliability when
critical parameters were not kept within narrow limits.
One thing that can cause this to happen is changes
in the precision resistor over time. Reference points in
the control process thus become less and less reliable.
Repeatability of the process from batch to batch begins
to drift. The process is changing while the monitors
appear to be holding it within specified limits because the
sense resistor is producing a different output voltage than
it was in previous runs for the same sensor output. So the
process appears to be under control when, in reality, it is
experiencing an undetected drift.
Long-term stability is thus one of the considerations that
drive the selection of which resistor technology to use in
the application.
But the typical permanent resistance drift of a Bulk Metal
Foil resistor is less than 60 ppm (0.006%) after 10 years
running at 0.1 W at 70°C.
By Sample Inspection:
• Environmental tests per table 3 on a quarterly basis
to establish performance by similarity
B. Test Conditions
• Lead test point: 0.5 in (12.7 mm) from resistor body
• Temperature: +23°C ±2°C
• Relative humidity: per MIL-STD-202
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Document No.: 63187
Revision: 01-Nov-2016
Z Series (Z Foil)
FIGURE 6 – LOAD LIFE TEST FOR
10 000 HRS @ 0.3 W +125°C; Z201, N=24
300.0
200.0
100.0
R
(ppm)
0.0
250
500
1000
2000
4000
6000
8000
10000
100R
1K
10K
FIGURE 7 – IMPROVED STABILITY
WITH THROUGH-HOLE
Through-hole achieve better stability because they are not subjected to
thermo-mechanical stresses from the PCB
A
Connection
Distant
from
Solder
Point
–100.0
–200.0
–300.0
PCB
Time (hrs)
A
A-A
THERMAL EMF
In a resistor, the resistance is composed of a resistance
element of one material and two terminations of a
different material. When the junction of the element and
the termination is heated in a closed circuit, there is a
DC voltage generated in the circuit (see Seebeck and
Peltier Effects). Hence, if both termination junctions
of the resistor are at exactly the same temperature
across terminations there is no net thermal EMF voltage
generated in the circuit due to thermal EMF error voltages
in the resistor.
In fact, however, the terminals are very seldom at the
same temperature because their temperatures are
influenced by uneven power dissipation within the
resistor, differential heating from other components
on the board, and heat conducted along the board
itself. Obviously, in a sense resistor that’s supposed to
accurately convert a current to a voltage, the presence
of an extraneous thermal EMF voltage could constitute
a significant error source in the system. That is why it’s
important that Bulk Metal Foil resistors have a thermal
EMF voltage of less than 0.1 mV/°C difference across the
element to termination junction.
POST MANUFACTURING OPERATIONS (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 reduce
drifts down the road. VFR 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
Resistors’ applications engineering for assistance in
choosing the PMO operations that are right for their
application.
TABLE 4 – “Z” SERIES SPECIFICATIONS
Stability (1)
Load life at 2 000 h
Load life at 10 000 h
Current Noise
High Frequency Operation
Rise time
Inductance (L)
(2)
Capacitance (C)
Voltage Coefficient
Thermal EMF
(4)
±0.015% (150 ppm)
±0.005% (50 ppm)
±0.050% (500 ppm)
±0.015% (100 ppm)
Maximum ∆R at 0.3 W/+125°C
Maximum ∆R at 0.1 W/+70°C
Maximum ∆R at 0.3 W/+125°C
Maximum ∆R at 0.1 W/+70°C
0.010 μV
RMS
/V of applied voltage (<–40 dB)
1.0 ns at 1 kΩ
0.1 μH maximum; 0.08 μH typical
1.0 pF maximum; 0.5 pF typical
<3 ppm/V
(3)
0.05 μV/°C typical
1 μV/W (Model Z201)
Notes
(1)
Load life ∆R maximum can be reduced by 80%, please contact applications engineering.
(2)
Inductance (L) due mainly to the leads.
(3)
The resolution limit of existing test equipment (within the measurement capability of the equipment.)
(4)
μV/°C relates to EMF due to lead temperature difference and μV/watt due to power applied to the resistor.
Document No.: 63187
Revision: 01-Nov-2016
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