This technical information has been contributed by
NKK Switches

Membrane Switch Keypads Simplify Interface Design

SCOTTSDALE, Ariz.--The FM Series of membrane switch keypads from NKK Switches (www.nkkswitches.com) is said to help simplify human-machine interface designs by replacing multiple mechanical switches, soldered wires, and cable assemblies with a compact, single-unit switching membrane mechanism. Dot-Illuminated models are available with 12 or 16 keys, and non-illuminated models with 4 or 16 keys. Both models include adhesive backing for easy mounting, the company says. Actuating domes are reported to offer crisp, tactile feedback to positively indicate circuit transfer.

Illuminated units have pre-configured legends on embossed keypads; the non-illuminated models have card insertion capability that supports customizable legends. Non-illuminated FM Series keypads are available with three customizable legend cards in yellow, gray, and black. Legend characters may be printed or drawn on the legend card. The FM Series membrane switch keypads are said to be suited for applications requiring a compact design and clean look, such as office, communication, automation, electronic, and entertainment equipment.

With a nominal operating force of 1.0N to 6.0N, these keypads offer an operational life of "1,000,000 operations, minimum," the company says. The stroke for illuminated models is 0.5mm to 1.2mm, and 0.4mm to 1.0mm for non-illuminated models. Both illuminated and non-illuminated keypad models are rated at 20mA @ 24V DC and have a dielectric strength of 250V AC minimum for one minute, minimum. The operating temperature range for the keypads is 5 degrees Fahrenheit to 122 degrees Fahrenheit.