Here is a selection of 10 resistors designed for harsh environments, including automotive and industrial applications.
Resistor manufacturers are facing a continuing demand for extended temperature ranges and AEC-Q200 qualified parts for automotive and industrial applications that require high stability in harsh environments.
At the same time, a continuing trend towards miniaturization is an additional challenge, as manufacturers are trying to deliver more performance in smaller capsules.
Also, in recent years, it has existed a greater need for anti-sulfur resistance. Sulfur contamination has been a major problem for the automotive industry, but it has become a more widespread challenge in other areas. Sulfur contamination affects the reliability of resistors in environments with high sulfur content, which can cause product damage.
The article shows the top 10 types of resistors that offer high reliability and stability or high temperature performance for a wide range of applications.
1. Bourns, anti-sulfur resistant CRxxxxA-AS model
Bourns Inc. offers a family of thick film resistors that are designed to work in harsh environments with a higher level of sulfur contamination. The CRxxxxA-AS series of resistors is manufactured using a thick film element printed on a ceramic substrate and tested according to ASTM B809-95 methods, which tests the porosity of metal coatings exposed to wet sulfur vapors.
Bourns said that Sulfur-resistant resistance have a lifespan about 20 times longer than the standard device.
The CRxxxxA-AS family of resistors can be used in a wide range of applications, from general to industrial use (industrial motor controls, pump controls and welding equipment), outdoor and road applications (lighting and traffic control).
AEC-Q200 compatible resistors are available in eight different capsules from 0201 (0603 metric) to 2512 (6432 metric), with a rated power from 0.05 W to 1 W. Resistance values range from 1 Ohm to 20 Mohms. This family of resistors is RoHS compliant. The operating temperature range is from -55 ° C to 125/155 ° C.
2. KOA Speer, SR73-RT series - current detection resistors
As the final (assembled) products continue to shrink, requiring smaller and smaller components, KOA Speer Electronics has added a 0402 capsule size to its SR73-RT series of anti-sulfur resistant current detection.
SR731E-RT is available in tolerances of ± 1%, ± 2% and ± 5% with resistance values from 1 Ohm to 10 Ohms and a rated power of 1/8 watt (W). The operating temperature range is from -55 ° C to 155 ° C.
Current sensing resistors use a special sulfur-resistant material, which makes them suitable for harsh environments with a high level of sulfur contamination. They can be used in mining, automotive, factory automation, agriculture, oil / gas and winemaking. The resistors are AEC-Q200 qualified.
3. KOA Speer, RN73R series - resistant with metal film
KOA Speer Electronics has launched its highly reliable RN73R series resistors with metal film to withstands applications with high heat and humidity, such as those found in car electronics, industrial equipment and medical devices. They can also be used as gain adjustment resistors for circuits with operational amplifiers.
The resistors offer electrolytic corrosion resistance and high stability compared to the existing RN73 thin film resistors from KOA. RN73R offers excellent heat tolerance, with an operating temperature range from -55 ° C to 155 ° C and a nominal ambient temperature of 85 ° C, as well as an improved humidity tolerance of 85% for 1.000 hours at 85 ° C.
The RN73R resistors provide rated powers (depending on the capsule) of 0.063 W (0402), 0.1 W (0603), 0.125 W (0805) and 0.25 W (1206) with a resistance range of 10 to 1.5 Mohm, the resistance tolerances ranging from ± 0.05% to ± 1%. The resistors are RoHS compliant.
4. Riedon, BR series - winding resistors
Riedon Inc. has expanded its manufacturing of coiled resistors with the new BR series of robust metal-plated resistors, targeting industrial and commercial applications such as motor drives, power conversion systems, HVAC systems and battery charging and monitoring applications.
The BR series, "wrapped" in aluminum radiators, is available in three different capsule types and offers a nominal power range. from 60 W to 500 W. These robust heaters ensure excellent heat transfer.
In the manufacture of these resistors, the company uses ceramic core instead of fiberglass. Ceramics offer greater efficiency by more efficient heat management during overloading and overvoltage events.
Resistors are available in flat (BR) or high (BRT) serial versions with quick connection terminations. They offer a resistance range from 0.1 ohm to 1 KOhm with tolerances of 1%, 5% and 10% and good long-term stability. The operating temperature range is from -55 ° C to + 200 ° C.
An ultra-thin version, the BRS series, is also available. Offering a 12 mm profile, the series offers rated powers from 100 W to 500 W and a resistance range from 1 Ohm to 5 KOhmi.
5. Stackpole Electronics, RTAN Series - Tantalum nitride resistors
RTAN tantalum nitride resistors from Stackpole Electronics offers robust resistance to moisture for applications requiring precision strength, stability and long-term reliability.
The RTAN series is designed with anti-sulfur materials and pass the ANSI / EIA-977 standard sulfur test (method A). The series is also compatible with the AEC-Q200. It is available in standard / common resistance values, with a tolerance of 0.1% in capsules of 0805 and 1206.
These resistors are used in the aerospace industry, testing equipment, industrial controls, portable diagnostic equipment for communications and portable medical devices.
6. Electronic Stackpole, HVAM precision resistors
For applications that require precision, very good stability, Stackpole Electronics offers HVAM resistors with axial conductors. These high voltage resistors are available in high resistance values 10 MOhm, 100 MOhm, 500 MOhm, 1 GOhm and 10 GOhm with powers from 2 W to 10 W. The operating temperature range is from -55 ° C to 225 ° C.
The series includes the following resistors:
HVAM20 with a rated power of 2 W up to 15 KV;
HVAM36 with a rated power of 3.6 W at up to 15 KV;
HVAM50 with a rated power of 5 W at up to 20 KV;
HVAM75 with a rated power of 7.5 W at up to 30 KV;
HVAM100 with a rated power of 10 W up to 50 KV.
These resistors can be used in a variety of medical applications, in circuit protection, in voltage dividers, in plasma welding and cutting equipment and high voltage power supplies.
7. TT Electronics, HDSC resistant
HDSC resistors (High Pulse Double-Sided Chip Resistors) are designed for protection and unloading in industrial and medical applications.
These resistors reduce field faults in applications exposed to electrical surges. They can withstand voltage peaks of up to 6.5 kV for an overvoltage of 1.2 kW / 50 µs and up to 6 kW for a pulse of 0.1 ms. The operating temperature range is from -55 ° C to 155 ° C. HDSC resistors are available in four sizes, from 0805 to 2512 and can be used to replace large capsules in circuits.
8. TT Electronics, EBW8518 bar mounted shunt resistor
TT Electronics offers E-Beam shunt resistors for industrial and automotive applications. EBW8518 is a welded resistance element, sandwiched between large copper terminals with optional tin plating. Suitable for precision applications, resistors offer 1% tolerance, and separate ground pins to reduce errors.
The technology of electron beam welding and low thermal EMF make shunt resistors particularly suitable for managing the operation of hybrid electric vehicle (HEV) batteries. These components are AEC-Q200 qualified.
EBW8518 offers resistance values from 50 micro Ohms up to 250 micro Ohms. It also improves reliability for designers who need to manage rising temperatures in compact electronic power assemblies.
9. Vishay, Power Metal Plate Current Detectors
Power Metal Plate Current Detectors from Vishay Intertechnology, Inc. are designed for harsh environments, from automotive and industrial to HVAC systems.
WFM resistors eliminates the need to run multiple resistors in parallel, which can cause current measurement errors. By using a single high power resistor, it improves the power density, which translates into space savings on the board.
WFM resistors offer rated powers of 2 W and 3 W in the capsule sizes of 2010 and 2512. The resistors have a resistive element made of manganese-copper or nickel-chromium solid metal with a low TCR of <20 ppm / ° C and low inductance values. from 0.5 nH to 5 nH. The operating temperature range is from -65 ° C to 170 ° C. These heaters are RoHS compliant.
The WFM resistors incorporate an improved thermal management design using a copper heat distributor that allows the heaters to maintain the electrical characteristics of the Power Metal Plate construction. Vishay also uses its own processing technique that allows for a wide range of low resistance values. from 5 MOhm to 500 MOhm, with tolerances of up to ± 1,0%.
They are suitable for a wide range of current and pulse detection applications. These include electronic vehicle controls, brushless DC motor controls, and battery management for electric and hybrid vehicles. They can also be used to control the inverter / high power converter.
10. Vishay, WSBS Power Metal Strip - shunt resistant
Vishay also offers a shunt resistor for harsh environmental conditions. The Power Metal Strip shunt resistors WSBS8518… 34 and WSBS8518… 35 are made of a resistive element made of solid nickel-chromium metal alloy and a "boot" design at their terminals. These improve the TCR performance (up to ± 10 ppm / ° C) for a better accuracy at extreme temperatures.
Applications include battery management in gas, diesel, hybrid and electric cars and trucks, as well as electric forklifts, large UPS systems and other heavy industrial applications.
Vishay Dale Power Metal Strip resistors, available in a 8518 capsule with a completely welded construction, offers a very low resistance, up to 100 micro Ohms, due to a patented technique and nominal powers up to 36 W. WSBS8518… 34 and WSBS8518… 35 offer low inductance values of <5 nH, low thermal EMF up to at <1.25 μV / ° C and an operating temperature range from -65 ° C to + 170 ° C. The resistors are RoHS compliant.