Low-profile, two-piece SlimShield board-level shields against electromagnetic interference feature a dimpled cover that snaps into etched holes on the fence. Supplied by Tech-Etch Inc. in standard and custom configurations for small medical electronic devices, the shields are available with heights as low as 0.060 in. and can be photoetched in any design. Standard dimple tooling offers economical variable dimple locations with good cover retention, and standard two-piece designs do not involve tooling costs, according to the company. Multicavity designs incorporate internal fences that enable multiple components to be shielded with just one part. An optional flange for added rigidity is available on larger fence designs. The shielding is mounted by means of pins and also through the use of a spring-finger-style attachment between the fence and cover.
Custom Push-Button Switches
MH-series glass-filled-nylon push-button switches are available in customized versions for medical design engineers seeking variety in a high-reliability switch. Whereas CIT Relay & Switch has always offered several LED color choices for this series, including bicolor illumination with and without an actuator, it now additionally offers a black actuator with a laser-etched on-off indication. The polycarbonate actuator operates within a force range of 500 gf ± 100 gf and travels 2.0 mm ± 0.2 mm. Featuring overtravel and positive detent, the switches have an electrical rating of 0.4 VA maximum at 20 V ac-dc maximum. Their rated electrical life is 50,000 cycles, contact resistance is under 50 mW, dielectric strength is 250 V rms, and insulation resistance is higher than 100 MW. They can be stored and operated within the temperature range of –20° to 70°C.
CIT Relay & Switch
The high-power, high-efficiency, I2C-controlled LTC4155 power-management system is a PowerPath manager, diode controller, and lithium-ion-battery charger suited for single-cell portable medical devices. This integrated circuit (IC) from Linear Technology Corp. is designed to efficiently transfer up to 15 W of power from a variety of sources while minimizing power dissipation and easing thermal-budgeting constraints. Its switching PowerPath topology seamlessly manages power distribution from two input sources, such as a wall adapter and USB port, to the device’s rechargeable lithium-ion battery while preferentially providing power to the system load when input power is limited. Because power is conserved, the IC allows the output load current to exceed the current drawn by the input supply, maximizing use of the available power for battery charging without exceeding the input supply power-delivery specifications. The device comes in a 28-pin 4 × 5-mm QFN package with a 0.75-mm profile.
Linear Technology Corp.
Wall-Mount Power Adapters
Manufactured by Tumbler Technologies + TrumPower, medical wall-mount switching power adapters in the TMW7 series are available either with a USB socket on the case or with an output cable with a dc plug, depending on the model. The adapters feature universal input of 90–264 V ac, 47–63 Hz, in fixed or interchangeable ac plug configurations. U.S., EU, UK, and Australian wall plugs are offered to meet worldwide requirements. Structured with Class II insulation, the series delivers 4 to 7 W of continuous output power and offers an output-voltage range of 3 to 28 V. The units have a low leakage current of 100 µA maximum at 264 V ac, 60 Hz. Fully protected against overvoltage, overload, and short-circuit conditions, the power adapters have a minimum efficiency of 67% at full load and feature standby power consumption below 0.3 W.
Tumbler Technologies + TrumPower
SANTA CLARA, CA
Single- and double-row solder-cup spring-pin header strips are a convenient and reliable means of providing connections between wires and mating components such as PCBs, batteries, and other cable assemblies. Offered by Mill-Max Mfg. Corp., the headers are suited for test and field wire-termination applications in which stack-up tolerances or blind mating may be a challenge. Each spring pin provides 0.0275 in. of midstroke compression and 0.055-in. maximum compression and is rated for 1 million cycles. The uniform orientation of the solder cups, which accommodate wire up to 22 AWG, makes it easy to solder cable or discrete wires to the spring pins because neither the wires nor the connector have to be manipulated. Securely soldering the wires in the cups results in a wired spring-loaded assembly that can function as an interface in discrete wire-to-board, cable-to-board, and cable-to-cable applications. Gold-plated brass components and beryllium copper springs ensure conductivity, corrosion resistance, and durability.
Mill-Max Mfg. Corp.
OYSTER BAY, NY
Ultraminiature TL4100- and TL4105-series tactile switches feature a distinctive board-edge mounting design and a life expectancy as long as 1 million cycles. Suitable for handheld devices, these switches from E-Switch Inc. offer a contact rating of 50 mA at 12 V dc; initial maximum contact resistance of 100 mΩ and 1Ω, respectively; insulation resistance of 100 MΩ (minimum) at 500 V dc; and dielectric strength of 250 V ac for 1 minute. Switch travel is 0.15 mm ± 0.10 mm. A choice of single-pole, single-throw, on-off, and momentary functionality is available. The switches operate between –40°C and 85°C.