Electronic Design

Components/Interconnects/Packaging> Overview

Retooling To Meet Advanced Electronic-System Needs

Progress, both evolutionary and incremental, never fails to keep the three foundation technologies of components, interconnects, and packaging in sync with the rest of the industry. Shrinking sizes, higher densities, and lower unit costs are attributes that dominate passive and active components like resistors, capacitors, inductors, potentiometers, relays, protection devices, oscillators, discrete displays, and sensors. Closely linked are developments surrounding interconnects and packaging, which have been nothing short of spectacular. While the world of silicon ICs is always basking in the limelight of faster, smaller, and cheaper, advances in components, interconnects, and packaging continue to make ICs more useful and practical.

Steadily shrinking resistors are exhibiting better thermal stabilities, greater power-handling capabilities, and tighter tolerances. Multilayer ceramic materials with low equivalent-series-resistance (ESR) values are making possible capacitance values of hundreds of microfarads with dc working voltages of 500 to 1000 V for use as filters in power-supply systems. And, costs are dropping from the $1/µF level down to $0.25/µF and lower.

Inductors additionally will benefit from material and process advances, resulting in serious size reductions. Many planar MEMS inductors have been produced with very high Q values for RF communication applications and cell phones.

Digital potentiometers are the newest rage. With no moving parts like those of their electromechanical cousins, these IC devices are resistant to shock and vibration, and offer longer lifetimes. They make use of a digitally controlled microcontroller to move the potentiometer's wiper arm.

Electromechanical relays, despite some shortcomings, are advancing and have become the choice of many designs offering advantages of low cost, ease of use, and efficiency. However, solid-state relays aren't staying complacent. In fact, they're narrowing the price/performance ratio gap with electromechanical types, becoming available in tiny leadless surface-mount packages. One interesting new application for solid-state relays is in portable battery-powered handheld power tools. Here, the solid-state relay provides greater power savings than its electromechanical counterpart as well as longer battery life.

Another class of components, electrostatic protection devices, will gain in stature as ICs work at lower voltage levels and become more susceptible to damage from transients. ESD protection devices will squeeze into very small packages that will complement the smaller footprints of dense ICs.

The venerable oscillator, a fundamental component in any design, is seeing greater use among instrumentation and military applications. The newest versions are low-cost monolithic silicon oscillators that feature performance parameters on a par with ceramic resonator and crystal oscillators.

Last year, Micro Oscillator showed that an all-silicon clock oscillator IC is practical with its MOI-2000. This low-cost device, which can be embedded into a microcomputer chip die, features frequency accuracy and temperature stability specifications comparable to those of ceramic resonator and crystal types.

In active display components, light-emitting diodes (LEDs) are becoming brighter and lower in cost. While the manufacture of economical white LEDs needs improvement, overall, LEDs continue to broaden their usage in handheld equipment and appliances, signage applications, and automotive applications. But they're also facing competition from organic LEDs (OLEDs) in backlighting and small-appliance applications like digital cameras and cell phones.

In fact, OLEDs are being readied for volume production in the large-area flat-panel-display arena. This is where liquid-crystal displays (LCDs) rule the roost, as do plasma-panel and electroluminescent displays. LCD panels for TVs have now reached 50 in. in diameter.

Interconnecting, integrating, and packaging all of these components into a viable working system still remains one of the most challenging aspects of design, as IC chip clock rates climb into the gigahertz sphere. Were it not for high-density packages, connectors, pc boards, and advanced materials, the high-speed advantages of gigahertz ICs would not be possible.

Performance improvements are being made in 3D, flip-chip, and wafer-level (chip-scale) packaging technologies, as well as in high-density substrate materials like low-temperature co-fired ceramics (LTCCs). LTCCs on metal substrates (LTCC-M) now offer improved thermal conductivities and lower shrinkage factors.

Connectors and terminal blocks are shrinking to accommodate the high-density requirements of modern electronic systems. A new class of nano-miniature connectors with center-to-center contact spacings of 0.025 in. is now emerging from Tyco Electronics. Also, connector manufacturers are finding out that they must work more closely with manufacturers of high-speed gigahertz ICs, as well as properly model their offerings in design-automation software, to ensure that the connectors work properly in a larger system.

One clear trend is a move to lead-free (no lead, pb) packages, brought on by a chorus of environmental concerns and regulations. Expect this trend to take off as more package manufacturers go this route.

TAGS: Components
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