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18 DESIGN007 MAGAZINE I FEBRUARY 2024 However, designing with embedded resis- tors requires careful consideration of several factors: • Resistance value and geometry. e sheet resistance of the resistor material (Rs) and the geometry of the etched resistor path determine the final resistance value. Designers can choose from various patterns and shapes, such as bar, serpen- tine, circular, or arc, to achieve the desired resistance. • Power handling and tolerance. Embed- ded resistors have power handling limita- tions similar to their discrete counterparts. Choosing the appropriate resistor size and material ensures reliable operation without overheating or exceeding toler- ance limits. • Design tools and resources. Fortunately, manufacturers of embedded resistor foils provide valuable design tools and resources to guide engineers through the selection and implementation process. ese tools aid in determining resistor dimensions, power dissipation, and tolerance based on specific design require- ments. e manufacturing process for embedded resistors involves precise photoresist appli- cation, exposure, development, and etching steps. e specific resistor alloy used, such as NiCr, NiP, NCAS, or CrSiO, influences the process parameters and final properties of the resistors. Careful control of the ohms per square (OPS) sheet resistance ensures consis- tent performance across production batches. Quantic Ohmega-Ticer offers several cop- per foil types including those with low-profile roughness for high-frequency circuit boards, minimizing signal loss. eir resistors work across diverse materials and applications. Final resistance tolerance depends on resistor foil tolerance, lamination effects, and PCB etching precision. ere are 70+ fabricators worldwide that offer reliable mass production of high-quality embedded resistors. Various resources, includ- ing a resistor calculator, help designers achieve desired tolerances and manage thermal dissi- pation. eir technology tackles space, pack- aging, and electrical challenges for millimeter- wave applications in both defense and com- mercial markets. DESIGN007 John Andresakis is director of business development for Quantic Ohmega-Ticer. Figure 2: A PCB with varying resistor values of 100 ohms/square.