Surface mounted device resistors

Ru02 resistors are commercial small-power (volume of few mm3) electronic components. They belong to the group of smd (surface mount device) thick-film resistors and are... 

Eccobond D125F/Henkel Stencil application for surface-mount devices (capacitors, resistors, small outline ICs, and plastic leadless chip carriers) N/A N/A N/A... 

A large and increasing part of the fixed resistor market is taken by surface mounted device (SMD) resistors. These resistors are mounted dhectly on the printed circuit board. Electrical contacts are provided at the sides of the resistor. 

Many wave designs are available from the various wave-solder machine manufacturers.There are wave machines that provide multiple smaller, turbulent wave(s), which are best for leadless components such as surface-mount passive devices (resistors, capacitors, etc.). Smoother-flowing waves are recommended for components with leads and through holes as well as coarse-pitch surface-mount devices. Wave dynamics are dictated by process values as well as the materials in contact with the wave. As the solder wets to the circuit board materials, solder wetting contact angle and solder viscosity imposes wave peel-off characteristics (see Fig. 47.23). 

The new user of surface mount designs (SMDs) must rapidly learn the packaging sizes and types for SMDs. Resistors, capacitors, and most other passive devices come in two-terminal packages, as shown in Fig. 11.17, which have end-terminations designed to rest on substrate pads/lands. 

These circuits are usually single- or double-sided ceramic substrates with a collection of surface-mount active components and screened-on resistors made from metallic pastes. They are most often found in hearing aids and other miniature devices. 

The trend in surface-mount technology is to use smaller passive devices such as capacitors, resistors, and inductors. Also, there is the use of embedded passive devices, that is, resistors and capacitors that are located within the circuit board laminate. Embedded passive devices free up additional surface area for larger, active components. 

FIGURE 40.12 (a) Stereo photograph showing surface-mount passive (chip) devices inductor, capacitor, and resistor (b-d) cross sections of their respective solder joints. (Courtesy of Sandia National Laboratories.)... 

FIGURE 55.1 A US penny shows the size of some common PC board components, some older, some recent. The small black devices near Lincoln s bow tie are 04-02 (40 x 20 mils) surface-mount resistors. (Now 02-01 [20 x 10 mils] devices are being used.) Some 100-, 75-, and 50-mil test probes are shown tor comparison. Note the lettering on the penny is done with 10-mil lines and the width of the circular part of the 9 is 35 mils, a common probe target size. (Photograph courtesy of Agilent Technologies )... 

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