IRC CHP Series Handbook
TT electronics
IRC - Wirewound & Film Technologies Division
736 Greenway Road
PO Box 1860
Boone, NC 28607 USA
1-828-264-8861
March 2003
CONTENTS
ii
1.0 INTRODUCTION
1.1 Product History
1.2 Product Description
2.0 PRODUCT MANUFACTURE, STRUCTURE, AND OUALITY CONTROL
2.1 Manufacture and Structure
2.2 Product Quality Control
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
3.1 Product Specifications
3.2 CHP Part Number Description
3.3 Power Derating
3.4 Surge Rating
3.5 Performance Characteristics
3.6 Product Dimensions
3.7 Recommended Solder Pad Dimensions
3.8 Soldering Methods
3.9 High Frequency Characteristics
3.10 Flammability
3.11 Thermal Performance
4.0 PRODUCT RELIABILITY ASSURANCE PROGRAM
4.1 Conformance Test Program Summary
4.2 Standard Test Conditions and Acceptance Criteria
5.0 PACKAGING
Appendix A. Control Plan
1.0 INTRODUCTION
1
1.1 PRODUCT HISTORY
IRC’s CHP family of surface mount resistors provides unsurpassed power density. From the 1206
¼-watt product (CHP1/8) to the current development of a 2010 1-watt offering (CHP1X), global CHP
customers capitalize on the inherent advantages of the CHP’s proprietary materials system and
construction.
The CHP surface mount resistor is a member of IRC’s precision Metal GlazeTM resistor product
family that has supplied billions of high-quality electronic components to the automotive, military,
computer, instrumentation, telecommunications, and industrial electronics markets for over 35 years.
IRC’s proprietary Metal GlazeTM technology provides an inherent and unsurpassed combination of
ruggedness, performance and low cost. The reliability of the Metal GlazeTM family is supported by
well over 1 billion unit hours of life testing with no failures.
The CHP uses the same resistive element as its established-reliability, military-qualified leaded
counterpart. IRC has supplied demanding customers with tens of millions of CHP resistors since
introducing the product in 1980, and has experienced no field failures. The CHP series, as all of
the Metal GlazeTM family, is manufactured in the United States at IRC’s Boone, North Carolina
facility, a QS-9000 registered facility.
1.2 PRODUCT DESCRIPTION
The CHP is a monolithic precision surface mount resistor with cylindrical geometry. The basis of the
component is a Metal GlazeTM resistive element, with a capless solder termination. The component
is available in several package sizes, allowing power rating between 1/8 and 2 Watts.
This unique construction not only provides a cost effective solution to common applications where
reliability is a major concern, but also offers some unique features to surface mount technology.
Some important characteristics of the CHP are listed below:
9 The inherent ruggedness of the Metal GlazeTM element can absorb
higher voltage surges and overloads than its thin film metal
oxide/metal film and thick film flat counterparts. The CHP can withstand
extreme temperatures resulting from to power overloads or circuit ambient
heating.
9 The CHP family offers high power density packages, including a 1/4-
watt 1206 footprint.
9 The CHP1X, currently under development, is expected to offer 1-watt,
70
°
C performance in a 2010 package.
9 Compared to surface-mount wirewound products, the CHP is extremely
cost competitive. IRC’s CHP series is often used by designers as an
1.0 INTRODUCTION
2
alternative to surface-mount wirewound components, allowing IRC
customers to enjoy a 30% - 60% cost savings.
9 The relatively simple design and construction of the CHP provides
benefits in long-term reliability. The product provides solder-dipped
nickel terminals, providing electrical continuity from the solder pad to the
resistive element without the need for end-caps or weld-joints. The Metal
GlazeTM technology provides a resistive element that is impervious to
environmental conditions without the need for an airtight encapsulation.
The cylindrical high alumina ceramic substrate provides excellent
thermal conductivity for maximum heat dissipation and provides superb
mechanical strength to withstand the stresses present during board
assembly, mounting, and operation.
9 The solder termination provides superb solderability. Unlike the typical
MELF components that use end-cap termination there is no dog-bone
shape to interfere with pick and place accuracy.
9 The CHP series offers resistance values as low as 0.050Ω, providing
customers with a cost-efficient, low-inductance current sense resistor.
9 The CHP offers a broad resistance range (0.050
Ω
- 2.2M
Ω
) in a limited
number of package sizes, simplifying IRC’s customers manufacturing
processes by reducing the number of packages required.
9 Several special products are available based on this product, including
Zero ohm jumpers (ZCHP), negative TCR components, and fully-
certified military products with DSCC drawings.
9 The CHP is offered with tolerance as low as
±
0.25% and TCR as low as
±
50 PPM/
°
C. These characteristics are provided without the tremendous
cost premiums required of flat thick-film competitors.
IRC is committed to quick delivery of the CHP. Non-standard resistance
values are available with a normal lead-time of 4 to 6 weeks. Expedited
delivery for customer demands exceeding the normal lead-time is available.
2.0 PRODUCT MANUFACTURE, STRUCTURE, AND QUALITY CONTROL
3
2.1 MANUFACTURE AND STRUCTURE
2.1.1 FIRING
The Metal GlazeTM process starts with a high-grade alumina rod. After a metal-to-glass ratio
has been determined (to achieve desired resistance value), milled glaze is applied by dipping
the rod and withdrawing it at a controlled rate for uniform film-thickness control
The dipped rods are then fired at approximately 1000°C. As the glass in the glaze melts and
flows during firing, It creates a form of microencapsulation of the metal particles in this
process, the glass also forms a strong bond with the vitreous phase in the alumina substrate
2.1.2 TERMINATING
After firing, the glazed rods are masked in preparation for diamond sawing to the desired
length and in preparation for several stages of chemical processing.
Following the application of a selectively plated electroless nickel termination and other
treatments, the elements are robotically solder dipped. The standard termination for the CHP
is 60% Sn / 40% Pb solder.
2.1.3 BINNING
The elements in a firing batch are automatically sorted into lots with narrow resistance bands
(“bins”). Resistors are manufactured from a sample of the batch and evaluated using a
standard series of tests before acceptance of the batch. These tests cover mechanical
characteristics, DC resistance, TCR, solderability and STOL. Accepted elements are then
stored until needed. This lot acceptance testing allows IRC continuous monitoring of its
manufacturing system.
2.1.4 ADJUSTING TO FINAL RESISTANCE VALUE
When an order is placed, IRC’s production staff select an appropriate “bin” to meet the
customer’s required resistance and TCR. The resistance value is determined by using a
laser to cut a helical path, increasing resistance, while a precision resistance bridge monitors
resistance. When the resistance value is reached, the equipment controller shuts off the
laser and verifies that the helical conductor path covers an acceptable fraction of the element
length. IRC accepts only those elements that meet resistance and helixing requirements.
2.1.5 APPLYING THE DIELECTRIC COATING
A dielectric coating is applied to the resistor to seal the surface of the component from debris
that could affect performance and provide a dielectric layer to the customer.
2.0 PRODUCT MANUFACTURE, STRUCTURE, AND QUALITY CONTROL
4
2.1.6 FINAL ELECTRICAL TEST AND PREPARATION FOR SHIPMENT
For the final stages of the process, the coated and spiraled element is tested to ensure
electrical tolerance requirements are met. Depending upon the resistance value, a high
voltage overload is applied to the element before the electrical test to enhance product
stability
After the test operation, the finished resistors are subjected to a Quality Audit using a "Zero"
defect sampling plan to ensure conformance to visual, mechanical, and electrical
requirements. Accepted product then advances to the packaging operation.
Note: The processes described above include the use of many proprietary materials and
techniques and are protected by IRC patents.
2.2 PRODUCT QUALITY CONTROL
It is the policy of IRC to be the industry leader in product quality. The company creates an
atmosphere and cultivates an attitude to motivate its employees to their highest potential of
excellence. We have a long-term goal of producing product with zero defects and pursue a strategy
of continual improvement of our products and services to achieve that goal.
This policy and related goals are incorporated in the CHP process to ensure the customer receives
the quality product it needs, when it needs it, and at a competitive price.
IRC adopts and practices the latest and most advanced control techniques available. These include
all the various applications of statistical process control (SPC). The company expresses the results
of its efforts in parts per million (PPM), anticipating a period when it will report its results in parts per
billion (PPB).
Metal Glaze
TM
thick film element
fired at 1000°C to solid ceramic
substrate
Hot solder-dipped,
nickel-plated
termination
2.0 PRODUCT MANUFACTURE, STRUCTURE, AND QUALITY CONTROL
5
IRC has attained leading facility and process quality certifications, including a MIL-qualified
environmental test lab, QS-9000 registration, and Ford’s Q1 qualification.
The CHP product is manufactured in accordance with documented Process Control Plans. The plan
provides for control of the entire process from raw material inspection to packing and shipping.
Special attention is paid to providing complete and accurate paperwork.
In-process control of quality is maintained by technicians, operators and maintenance personnel and
is monitored at checkpoints in the process by the quality control department. IRC has developed a
unique inline process average test (PAT) program that electrically stresses 100% of the components
and screens out components that underperform expected statistical results.
Appendix A presents the complete Process Control Plan for the CHP family.
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
6
3.1 PRODUCT SPECIFICATIONS
Industry
Footprint
IRC
type
Maximum
Power
Rating
Working
Voltage1 Max.
Voltage
Resistance
Range2, 3
Tolerance2
(±%)
TCR
(PPM/°C)
Product
Category
0.1Ω - 0.99Ω 1, 2, 5 100 Low Range
1.0Ω - 1 MΩ 1, 2, 5 50, 100 Standard
1206 CHP1/8
1/4W @ 70°C 200 400
20Ω - 348KΩ 0.25, 0.5 50, 100 Tight
Tolerance
0.1Ω - 0.99Ω 1, 2, 5 100 Low Range
2010 CHP1/2
1/2W @ 70°C 300 600
1.0Ω - 348KΩ 1, 2, 5 50, 100 Standard
0.1Ω - 0.99Ω 1, 2, 5 100 Low Range
1.0Ω - 2.21 M 1, 2, 5 50, 100 Standard
2512 CHP1
1W @ 70°C 350 700
20Ω - 350KΩ 0.25, 0.5 50, 100 Tight
Tolerance
0.2Ω - 0.99Ω 1, 2, 5 100 Low Range
3610 CHP2
2W @ 70°C,
1.33W @ 70°C 500 1000
1.0Ω - 2.21MΩ 1, 2, 5 50, 100 Standard
1Not to exceed SQRT(PXR)
2Consult factory for tighter TCR, tolerance, or resistance values not listed
3Zerohm CHPs available for each product type
3.2 CHP PART NUMBER DESCRIPTION
CHP1 - 100 - 2203 - F - 7
IRC TYPE
(CHP 1/8, CHP ½, or CHP1)
TEMPERATURE
(50 or 100 PPM)
RESISTANCE VALUE
(First 3 significant figures plus fourth digit multiplier)
Example: 2203 = 220 KΩ
51R0 = 51 Ω
R200 = 0.2 Ω
TOLERANCE
(C = ±0.25%, D = ±0.5%, F = ±1.0%, G = 2.0%, J = 5.0%
PACKING CODE
(7 = 7” reel; 13 = 13” reel
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
7
3.3 POWER DERATING
CHP POWER DERATING CURVE
0%
20%
40%
60%
80%
100%
120%
25 35 45 55 65 75 85 95 105 115 125 135 145
Ambient Temperature (C)
Percent of Rated Powe
r
CHP 1/8, 1/2, 1
CHP 2
3.4 SURGE RATING
The CHP demonstrates far superior surge performance to competing surface mount film products.
The reason for this performance stems from the mass of the deposited film. In short duration
(microseconds to milliseconds) overvoltage events typical of transient voltage spikes, the heat from
the power dissipation must be borne by the resistive film. In these situations, the mass of the film is
the critical feature for survival.
Metal film or metal oxide components are sputtered or evaporated, resulting in a “thin film” of
resistance material. The CHP resistance material is applied in a dipping process, leaving a much
thicker (typically 5 – 10 times thicker) film. The mass, therefore surge capacity, of the CHP is
accordingly higher.
The cylindrical geometry of the CHP provides an inherent surge advantage to flat “thick film” surface
mount components. Film mass, proportional to deposited area, is predictably greater on a cylindrical
CHP product component than on a flat product. Flat components are manufactured by depositing
material on only one side of the substrate. The area of the printed film is approximately W x L,
where W represents the element width, and L represents the element length. For a cylindrical
component, where the film coats the entire surface of the component, the area of the film is
approximately π x W x L. Comparison shows the CHP to have roughly 3 times the material as a flat
thick film product, explaining the CHP’s performance advantage over flat thick film chip resistors.
IRC has developed two surge charts presenting the surge capacity of the CHP. The charts vary
based on the repetitive nature of the surge events. If the component is subject to a continuous string
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
8
of repetitive surges but the time-weighted average power does not exceed the rated power of the
component, the user should refer to the repetitive surge chart. If the surges are more isolated, the
user should refer to the non-repetitive surge chart. In cases where the component will see a
repeated pattern of multiple surges but each cluster of surges is relatively isolated, the user should
consult IRC’s application engineering department for assistance.
In addition to limits on the component based on power dissipation, it is also important to note that the
component may reach voltage or current limits. CHP maximum voltage and current values are
shown below:
Size Range Max Peak Voltage
(V)1
Max Peak Current
(Amps)2
≤ 3 KΩ 1200 75
CHP1/8 > 3 KΩ 400 N/A
≤ 3 KΩ 1800 150
CHP1/2 > 3 KΩ 600 N/A
≤ 3 KΩ 2100 300
CHP1 > 3 KΩ 700 N/A
≤ 3 KΩ 3000 500
CHP2 > 3 KΩ 1000 N/A
1The maximum peak current only becomes a limitation for resistor values below approximately 16Ω. For example: an 0.5Ω
CHP1 would draw 4200A at 2100V. As the maximum peak current is 300A, the maximum peak voltage is determined by the
equation: Vpeak = Ipeak x R. In this case Vpeak = 300 x 0.5 = 150 Volts
2For mid to high resistor values (above 3 KΩ) the peak voltage applied becomes a more important consideration than power or
current (which are limited by the high resistance value). Unlike the effect of power and current which causes a positive and
potentially destructive change in resistance, the effect of excess voltage on mid- to high-range resistors is a negative change in
resistance. While this is not harmful to any of the properties of the resistor, the shift in resistance value may affect circuit
performance. By staying below the peak voltage indicated for values above 3 KΩ, the expected change in resistance will be
less than 0.25%.
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
9
CHP SERIES SURGE CAPABILITY
for Repetitive Surges
1.00
10.00
100.00
1,000.00
10,000.00
100,000.00
1,000,000.00
1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00
Surge or Pulse Duration (Seconds)
Peak Power (Watts)
CHP SERIES SURGE CAPABILITY
for Non-repetitive or Low Repetition Rate Surges
1
10
100
1,000
10,000
100,000
1,000,000
1.0E-09 1.0E-08 1.0E-07 1.0E-06 1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00
Surge or Pulse Duration (Seconds)
Peak Power (Watts)
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
10
3.5 PERFORMANCE CHARACTERISTICS
CHARACTERISTICS MAXIMUM CHANGE TEST METHOD
Temperature Coefficient As specified MIL-PRF-55342E Par 4.7.9
-55°C to +125°C
Thermal Shock ± 0.5% + 0.01 Ω MIL-PRF-55342E Par 4.7.3
-65°C to +150°C, 5 cycles
Low Temperature
Operation
± 0.25% + 0.01 Ω MIL-PRF-55342E Par 4.7.4
-65°C @ working voltage
Short Time Overload ± 0.25% + 0.01 Ω(R≤100KΩ)
± 1% + 0.01 Ω (R>100KΩ)
MIL-PRF-55342E Par 4.7.5
2.5 x SQRT(PxR) for 5 seconds
High Temperature
Exposure
± 0.5% + 0.01 Ω MIL-PRF-55342E Par 4.7.6
+150°C for 100 Hours
Resistance to Bonding
Exposure
± 0.25% + 0.01 Ω MIL-PRF-55342E Par 4.7.7
Reflow soldered to board at 260°C for 10
seconds
Solderability 95% Minimum Coverage MIL-STD-202, Method 208
245°C for 5 seconds
Moisture Resistance ± 0.5% + 0.01 Ω MIL-PRF-55342E Par 4.7.8
10 cycles, total 240 hours
Life Test ± 0.5% + 0.01 Ω MIL-PRF-55342E Par 4.7.10
2000 hours at 70°C intermittent
Terminal Adhesion
Strength
± 1% + 0.01 Ω
No Mechanical Damage
1200 gram push from underside of
mounted chip for 60 seconds
Resistance to Board
Bending
± 1% + 0.01 Ω
No Mechanical Damage
Chip mounted in center of 90mm long
board, deflected 5mm so as to exert pull
on chip contacts for 10 seconds
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
11
3.6 PRODUCT DIMENSIONS
INDUSTRY
FOOTPRINT
IRC
TYPE
L W C
1206 CHP 1/8
0.126 +0.010
-0.005
(3.2 + 0.25
- 0.15)
0.057 ± 0.006
(1.45 ± 0.15)
0.020 ± 0.010
(0.51 ± 0.25)
2010 CHP 1/2
0.200 ± 0.010
(5.08 ± 0.25)
0.079 ± 0.006
(2.01 ± 0.15)
0.030 ± 0.010
(0.76 ± 0.25)
2010 CHP 1X1 0.200 ± 0.010
(5.08 ± 0.25)
0.079 ± 0.006
(2.01 ± 0.15)
0.030 ± 0.010
(0.76 ± 0.25)
2512 CHP 1
0.251 ± 0.010
(6.38 ± 0.25)
0.057 ± 0.006
(1.45 ± 0.15)
0.040 ± 0.010
(1.02 ± 0.25)
3610 CHP 2
0.367 ± 0.010
(9.32 ± 0.25)
0.105 ± 0.006
(2.67 ± 0.15)
0.050 ± 0.010
(1.27 ± 0.25)
1The CHP 1X is a product under development.
3.7 RECOMMENDED SOLDER PAD DIMENSIONS
The proper solder pad size and geometry is dependent upon the type of soldering process used, the
size and type solder fillet expected to form on the CHP terminal and the power handling capability
expected of the CHP resistor.
The recommended solder pad design (shown below) will provide a large repeatable solder fillet to
the CHP resistor on IR and vapor phase reflow processes and wilI provide maximum heat transfer to
the PC board in high power applications.
Dimensions – Inches and (mm) Industry
Footprint
IRC
Type A B C D E F
1206 CHP 1/8
0.076
(1.93)
0.093
(2.36)
0.058
(1.47)
0.098
(2.49)
0.032
(0.81)
0.211
(5.36)
2010 CHP ½
0.111
(2.82)
0.126
(3.20)
0.096
(2.44)
0.152
(3.86)
0.040
(1.02)
0.318
(8.08)
2010 CHP 1X1 0.111
(2.82)
0.126
(3.20)
0.096
(2.44)
0.152
(3.86)
0.040
(1.02)
0.318
(8.08)
2512 CHP 1
0.121
(3.07)
0.126
(3.20)
0.127
(3.23)
0.183
(4.65)
0.040
(1.02)
0.369
(9.37)
3610 CHP 2
0.170
(4.32)
0.200
(5.08)
0.213
(5.41)
0.273
(6.93)
0.044
(1.12)
0.553
(14.05)
1
The CHP 1X is a product under development.
F
C
A
A
D
E
B
W
L
C
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
12
3.8 SOLDERING METHODS
The Rolling Myth: Despite the excellent production results enjoyed by the consumers of hundreds
of millions of CHPs, some customers are hesitant to accept a cylindrical component. By placing the
CHP on the solder paste while the paste is in the tacky state, the CHP will be held in position until
solder reflow begins. The pad design then uses the surface tension of the molten solder to pull the
component to the center of the solder pad. The excessive vibration that would be required to initiate
rolling from a CHP would also be associated with a number of soldering problems for today’s fine-
pitched surface mount components. IRC application engineers are available upon request to assist
customers in issues from circuit layout through component placement and soldering.
Recommended Soldering Practices: IRC’s customers have enjoyed success at a number of
soldering methods, including reflow, wave, and hand soldering. However, it is IRC’s experience that
infrared (IR) reflow soldering yields the most consistent high-quality solder fillets. Soldering
practices for several styles of soldering are presented below:
3.8.1 General Design and Assembly
General statement of best practices: Use IRC’s solder pad, avoid mechanical shock and
flexure, and avoid use of high-CTE substrates.
Solder Pads: IRC strongly encourages use of the recommended solder pad. The C-shaped
cutout or notch assists in self-centering the component and in forming an optimum solder fillet.
Mechanical shock: Mechanical stress can be imparted to the component through mechanical
shock in a number of ways. If board assembly is performed in a “multi-up” format, prior to circuit
board singulation, care must be taken not to flex the circuit during singulation. Additionally, board
flexure can take place while assembling a large connector or other component to the board, or
while inserting the circuit board into an edge connector or other mounting fixture.
PCB: IRC’s customers typically enjoy good success in soldering the CHP series to high-quality
board substrates like FR-4. Lower-quality substrates with high coefficients of thermal expansion
(CTEs) can lead to difficulties with all ceramic components.
3.8.2 Reflow
General statement of best practices: Infrared reflow is the most successful soldering method for
the CHP series. The customer should ensure that sufficient solder is available. Care should be
taken to ensure that adequate heat is applied to the component.
Stencil Thickness: IRC’s recommended solder stencil thickness is 0.007” (0.18 mm). The
minimum stencil thickness is 0.005” (0.13 mm). Less solder can lead to insufficient solder fillet
volume.
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
13
Placement Location: If the component is placed on the edge of the circuit board, ensure that the
temperature profile across the board is consistent. Insufficient heating can lead to a substandard
solder joint.
Shadowing: If the customer is using infrared (IR) reflow, large components can shield the CHP
from heating radiation. This shielding can cause insufficient heating and reflow of the solder joint.
Reflow temperature profile: Customers are advised to follow IRC’s reflow temperature curve
(provided below)
Reflow Method: Infrared reflow is the recommended assembly method. Other types of reflow
may be used, but IR reflow is the most commonly used method among IRC’s customers.
IRC Recomm ended Reflow Soldering Pr ocess Cycle
0
50
100
150
200
250
Time
Tem p (Deg C )
50 seconds > 183C
3.8.3 Wave Solder
General statement of best practices: IRC has noted a significant decrease in the use of wave
soldering over the past several years, as many customers have switched to reflow soldering as a
more reliable system. Minimize the size of adhesive dots to avoid mechanical stresses from TCE
mismatch between adhesives and the component.
Glue dots: The TCE mismatch between adhesives used for wave soldered components leads to
mechanical stress in the Z-axis, perpendicular to the circuit board. Minimizing the quantity of
adhesive applied will minimize this stress.
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
14
3.8.4 Hand solder/Rework
General statement of best practices: Hand-soldering is the most difficult to control method of
assembly and should be avoided if possible. If hand soldering is unavoidable, a temperature-
controlled soldering iron should be used (tweezer type if available), and operators should be
trained to avoid imparting excessive mechanical stress to the part. Alternatively, pneumatic
dispensers are useful to dispense a controlled amount of solder. In these cases, the solder is
usually reflowed by forced air.
Mechanical damage: A manual soldering iron provides a substantial (although undesired) lever,
and can easily damage the component or circuit board. This may be avoided by properly training
the operator in appropriate soldering technique.
Excessive heat / exposure: Tweezer-style soldering irons may be used to heat both terminals
simultaneously, avoiding some types of overheating. When possible, use a soldering iron with
digitally controlled temperature control.
Solder paste dispense/reflow: As an alternative to hand soldering, rework can be completed by
using a pneumatic dispenser to deposit a controlled amount of solder paste on the PCB. Reflow
is performed usually by directed hot air flow or by IR reflow
3.9 HIGH FREQUENCY CHARACTERISTICS
For IRC CHP products below 150Ω, the high frequency model looks like a resistor with a small
amount of effective series inductance. The inductance varies with the helix path required in value
adjustment manufacturing step (see Section 2.1.4) and material selection. However, some
generalizations are appropriate, and are provided below.
For resistance values below 30Ω, the series inductance has a value of 3-10 nanohenries (nH) for the
CHP1/2 and CHP1/8 and 6-15 nH for the CHP1 and CHP2.
For values between 30Ω - 80Ω, the amount of inductance reaches its maximum value at a level of
10-15 nH for the CHP1/8 and CHP/.2 and 15-20 nH for the CHP1 and CHP2. These maximum
values may be lowered to the levels below 30Ω by using special spiraling method for the customers
requiring optimum high frequency performance.
From 80Ω-150Ω, the series inductance falls off to zero as the capacitive effects of the film
dominates.
For IRC CHP products above 150Ω, the HF model becomes a resistor shunted by a very small
capacitance. The effective value is 0.1 picofarad (pF) for the CHP1/8 and CHP1/2, and 0.15 pF for
the CHP1 and CHP2.
3.10 FLAMMABILITY
Because the dielectric coating of the CHP is very thin, the CHP is nearly 100% inorganic; hence, the
flammability of the product is very low. The CHP qualifies as a UL-V0 component.
3.0 PRODUCT ELECTRICAL, ENVIRONMENTAL, AND MECHANICAL
CHARACTERISTICS
15
3.11 THERMAL PERFORMANCE
The CHP’s high-grade alumina core provides excellent thermal transfer, resulting in even
temperature across the component. The CHP thermal impedance (°C/watt) is lower than or equal to
competing technologies, as shown in the figure below.
2512 Surface Mount
Temperature Rise Comparison
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
0.00 0.25 0.50 0.75 1.00 1.25 1.50
Applied Power (Watts)
Temperature Rise (C)
CHP Hot Spot Flat TF Hot Spot SM WW Hot Spot CHP Solder Joint
Flat TF Solder Joint SM wW Solder Joint
Resistor Hot S
p
ot
Solder Joint Tem
p
eratur
e
4.0 PRODUCT RELIABILITY ASSURANCE PROGRAM
16
4.1 CONFORMANCE TEST PROGRAM SUMMARY
In addition to various controls built into the CHP process to ensure product reliability, a test program
has been set-up to randomly monitor the performance of the CHP product. IRC maintains the data
from the conformance test program and will provide these data to customers upon request. The
following summary describes the performed tests. The following Chart summarizes this monitoring
system:
Characteristics Maximum Change Test Method
Test
Frequency
Temperature
Coefficient
By TCR requirements MIL-PRF-55342E Par. 4.7.9
-55°C to +125°C
Weekly
Thermal
Shock
±0.5% + 0.01Ω MIL-PRF-55342E Par. 4.7.3
-65°C to +150°C, 5 cycles
Monthly
Low Temperature
Operation
±0.25% + 0.01Ω MIL-PRF-55342E Par. 4.7.4
-65°C at working voltage
Weekly
Short Time
Overload
±0.25% + 0.01Ω (R≤ 100
KΩ)
±1.0% + 0.01Ω (R>100 KΩ)
MIL-PRF-55342E Par. 4.7.5
2.5 x SQRT(PxR) for 5 sec
Weekly
High Temperature
Exposure
±0.5% + 0.01Ω MIL-PRF-55342E Par. 4.7.6
+150°C for 100 hours
Quarterly
Resistance to Bonding
Exposure
±0.25% + 0.01Ω MIL-PRF-55342E Par. 4.7.7
Reflow soldered to board at 260°C for 10
seconds
Weekly
Solderabilty
95% minimum coverage MIL-STD-202, Method 208
245°C for 5 seconds
Monthly
Moisture
Resistance
±0.5% + 0.01Ω MIL-PRF-55342E Par. 4.7.8
10 cycles, total 240 hours
Quarterly
Life Test
±0.5% + 0.01Ω MIL-PRF-55342E Par. 4.7.10
2000 hours at 70°C intermittent
Quarterly
4.2 STANDARD TEST CONDITIONS AND ACCEPTANCE CRITERIA
4.2.1 RESISTANCE VALUE
Procedure: Measurements to be made at 25°C ±2°C (MIL-PRF-55342 para. 4.7.2)
Acceptance criteria: Reading must be within the specified tolerance at the nominal value.
4.2.2 TEMPERATURE COEFFICIENT
Procedure: Readings to be taken at 25°C -55°C, 25°C, 125°C MIL-PRF-55342 para. 4.7.3)
Acceptance criteria: Reading must not exceed criteria as specified in the applicable plan
drawing
4.2.3 THERMAL SHOCK
Procedure: 5 cycles from -65°C to 150°C. MIL-PRF-55342 para. 4.7.3)
Acceptance criteria: Change in resistance from the initial reading not to exceed ±0.5% ±
0.01Ω.
4.2.4 LOW-TEMPERATURE OPERATION
Procedure: Expose to -850C for one hour Load at full rated continuous working voltage for 45
min. Power off for 15 min. (MIL-PRF-55342 para. 4.74)
4.0 PRODUCT RELIABILITY ASSURANCE PROGRAM
17
Acceptance criteria: Change in resistance from the initial reading not to exceed ±0.25%
+0.01Ω
4.2.5 SHORT-TIME OVERLOAD
Procedure: Apply 2.5 times the rated continuous working voltage for 5 seconds. (MIL-PRF-
55342 para. 4.7.5)
Acceptance criteria: Change in resistance not to exceed ±0.25% +0.01Ω for values less than
100KΩ and not to exceed ± 1.0% for values above 100KΩ.
4.2.6 HIGH-TEMPERATURE EXPOSURE
Procedure: Expose to +150°C for 100 hours (MIL-PRF-55342 para. 4.7.6)
Acceptance Criteria: Change in resistance not to exceed ±0.5% +0.01Ω
4.2.7 RESISTANCE TO BONDING EXPOSURE
Procedure: Reflow solder to board at 260°C for 10 seconds (MIL-PRF-55342 para. 4.7.7)
Acceptance Criteria: Change in resistance not to exceed ±0.25% +0.01Ω
4.2.8 SOLDERABILITY
Procedure: Immerse resistor in flux for 5 seconds, immerse in 245° solder for 5 seconds.
(MIL-PRF-55342 para. 4.7.11)
Acceptance Criteria: Solderable area to be 95% covered by new solder
4.2.9 MOISTURE RESISTANCE
Procedure: Apply 10 cycles for a total of 240 hours (MIL-PRF-55342 para. 4.7.8)
Acceptance Criteria: Change in resistance not to exceed ±0.5% +0.01Ω
4.2.10 LIFE TEST
Procedure: Intermittent load for 2000 hours at 70°C. (MIL-PRF-55342 para. 4.7.10)
Acceptance Criteria: Change in resistance not to exceed ±0.5% +0.01Ω
4.2.11 TERMINAL ADHESION STRENGTH
Procedure: Apply 1200 gram push from underside of mounted CHP for 60 seconds.
Acceptance Criteria: Change in resistance not to exceed ±1.0% +0.01Ω and no mechanical
damage.
4.2.12 RESISTANCE TO BOARD BENDING
Procedure: CHP mounted in center of 90 mm long board and deflected 5 mm so as to exert
pull on CHP contacts for 10 seconds.
Acceptance Criteria: Change in resistance not to exceed ±1.0% +0.01Ω and no mechanical
damage.
5.0 PACKAGING
18
CHP resistors are reel taped on standard 4mm pitch anti-static plastic embossed tape in accordance
with the requirements of EIA 481 to support high speed automated component feeding processes. The
chart below summarizes the reel sizes, number of components per reel and carrier tape width for the
CHP product family.
INDUSTRY
FOOTPRINT
IRC
TYPE
REEL
DIAMETER
QUANTITY
PER REEL
CARRIER
TAPE WIDTH
1206 CHP1/8 7”
13”
2,500 max.
10,000 max.
7 Mm
8 mm
2010 CHP1/2 7”
13”
1,500 max.
5,000 max.
12 mm
12 mm
2512 CHP 1 7”
13”
1,500 max.
5,000 max.
12 mm
12 mm
3610 CHP 2 13” 1,500 max. 24 mm
Appendix A. Quality Control Plan
19
CONTROL PLAN
IRC, INC.
BOONE, NC
Control Plan Category Key Contact Name/Phone Date (Orig) Date (Rev) Page
Jerry Garland
828-264-8861
12/18/90 2-26-02
Control Plan Number Core Team Customer Engineering Approval (If Req'd) Date (If Req'd)
N/A QC/Eng./Mfg. N/A
Part Number ECL Supplier / Plant Approval / Date Customer Quality Approval (If Req'd) Date (If Req'd)
CHP 1/8, 1 & 2 Watt 12/18/90 N/A
Part Name / Description Other supplier approval by (If Req'd) Other Approval (If Req'd) Date (If Req'd)
CHP Resistor Series (Generic) N/A N/A
Supplier / Plant Supplier Code Other Approval Date (If Req'd)
Boone, NC N/A
Characteristics Methods
Part /
Proc #
Process Name /
Operation description
Machine, Device, Jig,
Tools For Mfg.
No. Product Process Special
Char.
Class.
Product / Process
Specification /
Tolerance
Evaluation /
Measurement
Technique
Sample
Size
Sample
Freq.
Control Method Reaction Plan
1 Receiving
Inspection
N/A A Visual/
Mechanical
N/A Print Dimension/
Specification
Calipers/Comp
Lab Evaluation
C=0 Each
Lot
Inspection
Data/Lab
Results
Reject lot, return to vendor for
corrective action.
2 Glaze
Preparation
N/A B Glaze Viscosity N/A Nominal ± 15 Viscometer 1 Twice
per
shift
X&R Control
Chart
Adjust Viscosity per MP-
3610-12-0100 (Eng.
Assistance).
3 Glaze Application
(Rod Dip)
Glaze Dip Station C Dip Rate N/A Specified
Tolerance Per
Size
Stop Watch 4 Once
Per
Shift
X&R Control
Chart
Adjust machine speed per
MP-3610-12-0300
4 Glaze Firing Kiln D Glaze Thickness N/A 0.0004 - 0.0016 Micrometer 5 Hour X&R Control
Chart
Adjust kiln temperature/glaze
viscosity per MP-3610-12-
0400 and QC-3610-12-0400
(Eng. Assistance).
4 Glaze Firing Kiln E Rod Resistance N/A Specified
Tolerance Per
Glaze Type
Resistance
Bridge
10 Hour Control Log
Histogram
Adjust kiln temperature/glaze
viscosity per MP-3610-12-
0400 and QC-3610-12-0400
(Eng. Assistance).
Appendix A. Quality Control Plan
20
5 Rod Potting Potting Molds/P-9
Gun
F P-9 Temperature/
Percent
Shrinkage
N/A 72 - 84° F/
0.20 - 0.90%
Thermometer/
Calipers
1 Once
Per
Shift
Control Log Adjust temperature/mixture
per MP-3610-13-0400 (Eng.
Assistance).
6 Rod Sawing Saw G Wafer Thickness N/A Specified
Tolerance Per
Size
Digital
Indicator
10
Each
Head
Set-
Up/
Blade
Chnge
X&S Control
Chart
Change gears/saw blade per
MP-3610-14-0100
6 Rod Sawing Saw H Saw Cut Speed N/A Specified
Tolerance Per
Size
Stop Watch 1 Once
Per
Shift
Control Log Adjust machine speed per
MP-3610-14-0100.
7 Etch Back Etch Back Tanks I Etch Back Thickness N/A Specified
Tolerance Per
Size
Calipers 5 Once
Per
Shift
X&R Control
Chart
Adjust etch back time per
MP-3610-15-0200 (Eng.
Assistance).
8 Slug Tinning Solder Dip
Machines
J Solder
Temperature
N/A 285 ± 10° C
60/40 Solder
Computer
Readout
1 Once
Per
Shift
Control Log Adjust process per MP-3610-
16-0100 and QC-3610-16-
0100
8 Slug Tinning Solder Dip
Machines
K Flux Specific
Gravity
N/A N/A Computer
Readout
1 Once
Per
Shift
Control Log Adjust process per MP-3610-
16-0100 and QC-3610-16-
0100
8 Slug Tinning Solder Dip
Machines
L Dwell Time N/A Specified Value
Per Size
Stop Watch 1 Once
Per
Shift
Control Log Adjust process per MP-3610-
16-0100 and QC-3610-16-
0100
9 Slug Culling Cullers M Slug Diameter N/A Specified
Tolerance Per
Size
Mechanical
Screening
100% 100% Follow MP-
3610-17-0200
Review/correct process (Eng.
Assistance).
10 Slug Binning Binners N Slug Length N/A Specified
Tolerance Per
Size
Electronic
Measurement
System
100% 100% Follow MP-
3610-18-0100
Review/correct process (Eng.
Assistance), 100% re-bin lot.
11 Department 20
Spotcheck
N/A O Visual/Electrical/ Mechanical/GLA N/A Zero Defects Visual/Res.
Bridge/Lab
Evaluation
Per
Proce
dures
Each
Lot
Follow QCP-
3610-18-0X00
Review inspection
data/correct process
(Eng./QC).
12 Spiraling Spiraler P DC Resistance N/A Specified
Tolerance
ESI
Resistance
Bridge
5 Three
Per
Shift
X&R Control
Chart
Adjust spiraler per MP-3610-
19-0402
13 Coating Coater Q Dielectric Strength N/A 125 VAC
Minimum
Dielectric
Tester
10 Each
Order
Review
Inspection
Data
Adjust coater per MP-3610-
24-0220, 100% re-coat lot.
Appendix A. Quality Control Plan
21
14 Visual Inspection N/A R Visual/ Mechanical N/A Zero Defects Calipers/
Microscope
C=0 Each
Order
Follow QC-
3610-34-
0100C
Review inspection
data/correct process
(Eng./QC).
15 Packaging Test/Tape S Tape Peel Strength N/A 10 - 63 Gr. Peel Strength
Tester
1 Set-
Up/
Tape
Chnge
X&R Control
Chart
Adjust taping machine per
MP-3610-37-0500
15 Packaging Test/Tape T Short Time Overload N/A Zero Defects STOL
Equipment
100% 100% Follow MP-
3610-24-0230
Review process/correct
deficiency (Eng.)
15 Packaging Test/Tape U DC Resistance N/A Specified
Tolerance
Resistance
Tester
100% 100% Follow MP-
3610-24-0230
Review process/correct
deficiency (Eng.)
16 Electrical
Inspection
N/A V DC Resistance N/A Zero Defects ESI
Resistance
Bridge
C=0 Each
Order
Follow QC-
3610-34-
0100C
Review inspection
data/correct deficiency
(Eng./QC).
17 Dock Audit N/A W Visual/Packaging/Clerical N/A Zero Defects Visual 100% Each
Order
Follow QC-
3610-40-0100
Review process/correct
deficiency.
24
TT electronics
IRC - Wirewound & Film Technologies Division
736 Greenway Road
PO Box 1860
Boone, NC 28607 USA
