RCM is used in almost all areas of the electronics industry: consumer electronics, military/aerospace, commercial space, data centers, telecommunications, automotive, and medical electronics. Key applications include AESA Radar, MEMS Packages, Antennas, RF Filters/Electromagnetic Absorber, Sensors, Interposer Circuits, and Circuit Foil Heaters. RCM resistors are used as a resistor element and can be used as a direct replacement for discrete resistors. It is particularly beneficial for high-frequency RF resistors in Wilkinson Power Divider structures as well as termination, pull-up/pull-down resistors, series and parallel terminating resistors, isolation resistors and heater elements.

RCM’s strength has been its ability to be used in a variety of new ways in new applications. It acts like a resistive “blank slate” – providing the PCB designer with a key tool for addressing contemporary electronic issues requiring passive resistors or resistive films.

The cost of using RCM is dependent on the material price, the conversion cost that is applied to a printed circuit board by the board shop and any reduction in the overall board cost due to design enhancements. In addition to eliminating discrete surface mount resistors (SMT) and their assembly costs, PCB cost reduction is achieved by smaller board form factors, reduced layer counts, and the use of conventional PCB technologies rather than more expensive build-up and/or high-density interconnect (HDI) technologies. In general, RCM becomes more economical to use as a replacement for chip resistors when the resistor density increases. Although the use of embedded resistors may in some cases reduce the overall cost of a board, in general the technology is used to enhance circuit performance.

Sheet resistivity is the resistance in ohms per square and is a dimensionless number. The value of any specific resistor is determined by the ratio of the length of the resistor to its width multiplied by the sheet resistivity used (R= L/W x Rs).  Consultation with Quantic Ohmega on specific design criteria and guidance is available. Design resources can also be found in the Technical Library. 

• Availability: RCM is available as a foil, or through global material suppliers as a laminated product.

• Compatibility: RCM is profiled and tested with a wide variety of resin systems, including standard, high performance, lead-free and specialty resins. All RCM materials are ROHS compliant.

• Design Versatility: Nickel Phosphorous, Nickel Chromium (NiCr), Nickel Chromium Aluminum Silicon (NCAS), Chromium Silicon Oxide (CrSiO) alloys are available in a range of sheet resistivities (Ohm/Square) allowing typical resistor values from 5 to 50k ohms.

• Product Performance & Predictability: Low thermal coefficient of resistivity minimizes change in foil resistance during lamination. Predictability and consistency lot-to-lot and sheet-to-sheet are ensured through extensive testing under varied lamination conditions.

• Uniformity: Precision plating or vacuum metallization ensures uniform ratios of the elements in the deposited alloy, resulting in minimal resistance variation. Final etching tolerances benefit from RCM’s thin and uniform resistive layer.

The RCM laminate is processed by PCB manufacturers using their standard subtractive print and etch process to create the initial circuitry and repeating a second time to define the resistor element. Any PCB shop can process RCM. No license or other fee is required. Since standard equipment, chemistries and process consumables are used there is minimal capital investment required by the board shop to process RCM. Most electrical test equipment can be used with a software upgrade to enable resistor testing – see the Technical Library for more information.

RCM embedded resistor technology has been used in numerous applications since the early 1970s. Over the decades it has exhibited excellent long-term stability and reliability and has become the technology of choice in many critical circuit applications. In the millions of printed circuit boards, and trillions of component hours of use, RCM has demonstrated absolute reliability. RCM resistors in new designs are an application of a mature, well proven, technology.