Originally Published MPMN July/August 2002

PRODUCT UPDATE

Small and Mighty

Electronic components are becoming ever more efficient

Susan Wallace

The field of electronic components spans many types of products, from diodes to EMI and RFI shielding devices to crystals and oscillators. One of the things they all have in common is a trend toward a reduction in size accompanied by an increase in power. In this article, MPMN takes a look at some of the new electronic products that have been designed for medical device applications.

LEDs save space

Surface-mount LEDs feature pixel lenses that provide a wide viewing angle in a discrete configuration. Pix-Tek LEDs from Bivar Inc. are based on a patented technology that offers increased space and labor-saving economies over traditional through-hole mounting, while incorporating standard through-hole geometry that narrows the radiation patterns and eliminates light loss.

The 5-mm square and 5-mm round packages offer 50° and 25° viewing angles, respectively. They are available in many colors including RGB, white, and ultraviolet, with wavelengths from 400 to 600 nm.

The LEDs are suitable for moving message signs, general indication displays, and backlighting.

Switches last many cycles

A series of rocker switches satisfies most higher power ratings—up to 15 A at 125 V ac or 10 A at 250 V ac, as well as peak currents up to 150 A at 250 V ac for selected models. The 2600-series units from Apem Components Inc. also offer minimum electrical life of 10,000 cycles at full load.

The single- and double-pole models are available in on-on, on-off, and on-off-on electrical configurations, with two or three positions. Other specifications include initial contact resistance of 10 mΩ maximum, and dielectric strength of 2500 V rms/per minute between terminals and 3000 V rms between terminals and the metal mounting panel.

All models have a bezel size of 0.984 x 1.259 in. and project through a front panel 0.890 in. They snap fit into a 0.866 x 1.181-in panel cutout. Materials include a high-temperature plastic case, polyamide actuator and frame, and silver or silver-plated copper contacts. Terminal choices include ¼-in. solder lugs and quick connects or screw and clamp types.

Power inductors minimize board space

Surface-mount power inductors from Gowanda Electronics have been created to enable engineers to design circuitry with high current-handling capability and minimal board space.

The SMP 1812 series of surface-mount power inductors is targeted for use in dc/dc convertors and power supply applications in which high performance and small size are critical. The SMP 1812 inductors have an inductance from 1 to 330 µH, current ratings from 124 to 2018 mA, and saturation current from 129 to 2500 mA. An RF version of the series is also available.

Clock oscillators feature low voltage or low current

Ultra-low-voltage and low-current HCMOS clock oscillators are suitable for applications in which a long sustainable battery life is a prime consideration. The ultra-low-voltage HCMOS clock from Raltron Electronics Corp. is available at 1.6 V and 20 mA, with a frequency range of 30 to 70 MHz. The low-current HCMOS clock features a supply current as low as 3.0 mA at 2.7 V or 3.3 V with an upper rating of 4.6 mA at 5 V. Its frequency range is from 4.0 to 30 MHz. Both clocks offer a low jitter specification of 1.0 picosecond rms and optional temperature ranges from 0° to 50°C to –20° to 80°C.

Standard frequency stability is ±50 ppm, and tighter tolerances are available. Both series come in a 5 x 7- mm package with a low profile height of 2.0 mm maximum.

Linear ac power sources are small but powerful

High-performance linear ac power sources have output ranges from 500 VA to 12 kVA in single-phase, split-phase, or three-phase mode. The AMX-series units from Pacific Power Source can produce high-quality, low-distortion output by combining a broad, 50-kHz small-signal bandwidth with a peak-to-rms-current ratio of 4–6:1. The instruments were designed to operate quietly and to use limited space efficiently, providing maximum power per cubic inch of rack space.

Some features of the power sources include output power with paralleled units up to 30 kVA, programmable or manual controllers, IEEE 488.2 or RS-232 with SCPI protocol, 6:1 peak current capability, continuous self-calibration, programmable output impedance, and programmable time- and cycle-based transients.

Single-board computer operates in extreme temperatures

A single-board computer is offered in an extended-temperature configuration. The VSBC-8 from VersaLogic Corp. has a 350-MHz Celeron cpu and operates at –40° to 85°C. The unit comes with PC/104-Plus expansion, AGP video with flat-panel support, 10/100 BaseT Ethernet, sound support, and up to 256 Mbyte of SDRAM.

On-board features include Opto 22–compatible digital input and output ports, four COM ports, and three extra timers.

The high-reliability design includes a cpu temperature sensor, latching input and output connectors, and a latching memory socket. Each board is subjected to a 48-hour burn-in, and 100% functional testing.

The computer is compatible with a wide range of popular operating systems.

RFI/EMI shielding gaskets feature snap-on mounting

Two variable-finger snap-on edge-mount gaskets offer RFI/EMI shielding effectiveness up to 100-dB attenuation. One side of the V-series Finger Stock BeCu gaskets from Tech-Etch Inc. hooks over the edge of a flange while fingers on the opposite side snap into slots. Each gasket is offered in five different finger, or slot, patterns.

Snap-on mounting provides fast, secure installation with high durability. No adhesive or fasteners are required. Featuring a no-snag design, the units are suitable for bidirectional applications, require only a low closing force, and close gaps as small as 0.01 in.

Copyright ©2002 Medical Product Manufacturing News