Resistor, Capacitor Networks Information

Resistor, Capacitor Networks Information

Resistor, capacitor networks (RC networks) are integrated circuits (ICs) that contain resistor-capacitor arrays in a single chip. Some resistor, capacitor networks are used to suppress transmission-line effects on high speed data lines in order to improve system performance and reduce the cost of passive components. Other RC networks allow loads to be attached anywhere along a line without direct current (DC) power dissipation. Typical applications for resistor, capacitor networks also include the suppression of electromagnetic interference (EMI) and radio frequency interference (RFI) at the input/output (I/O) ports of personal computers (PCs) and peripherals, workstations, local area networks (LANs), wide area networks (WANs), and asynchronous transfer mode (ATM). 

Technologies Used

Resistor, capacitor networks use four basic technologies: metal film, thick film, thin film, and wirewound. Metal film RC networks are similar to metal oxide resistors and are used in simple circuits. Thick film technology combines the advantages of circuit miniaturization with increased reliability, low weight, and low cost at medium to high volumes. Using a thick film circuit with a printed circuit board (PCB) offers reduced component costs, lower assembly costs, quicker assembly and test times, and increased reliability. Thin film devices include a microscopically thin layer of semiconductor or magnetic material that is deposited onto a metal, ceramic, or semiconductor base. Semiconductor materials include copper indium diselenide, cadmium telluride, gallium arsenide, and amorphous silicon.  Thin film technology is the preferred solution for applications that require low noise levels, long term stability and excellent performance at very high frequencies. By contrast, wirewound resistor, capacitor networks are simple components that are often wound by hand.

Specifications

Important specifications for resistor, capacitor networks include resistance and resistance tolerance, the percentage deviation from a nominal resistance value. Other considerations include temperature coefficient, capacitance, and power rating. The temperature coefficient is the change in resistance as a function of temperature. Capacitance, a measure of energy storage ability, is typically expressed as C = K A/D, where A is the area of the electrodes, D is their separation, and K is a function of the dielectric between the electrodes. The power rating for RC networks is the total power dissipation in watts. 

Mounting Styles

There are two mounting styles for resistor, capacitor networks. Through hole technology (THT) mounts components on a PCB by inserting component leads through holes in the board and then soldering the leads in place on the opposite side. Surface mount technology (SMT) adds RC networks to a board by soldering component leads or terminals to the top surface. Typically, the PCB pad is coated with a paste-like formulation of solder and flux. With careful placement, SMT components on solder paste remain in position until elevated temperatures, usually from an infrared oven, melt the paste and solder the component leads to the PCB pads.  

Resistor, capacitor networks are packaged in tape reels, trays or rails, shipping tubes or stick magazines, and in bulk packs. Tape reel assemblies include a carrier tape with embossed cavities for storing individual components. A cover tape seals the carrier tape in place and the composite tape is wound on a reel that can be loaded into industry-standard, pick-and-place board assembly equipment. Resistor, capacitor networks with leads on four sides are often packed in trays or rails that are made of carbon-powder or fiber materials and molded into rectangular outlines that contain matrices of uniformly spaced pockets. Shipping tubes or stick magazines are containers made of rigid polyvinylchloride (PVC) and extruded in industry-standard sizes. Bulk packs are used to distribute RC networks as individual parts.