Ultra-low Profile Dome Key B3D Single-key Type Added to Series of B3DA Ultra-low Profile Dome Arrays • No soldering required. Attach directly to PCB to make an ultra-low profile tactile switch. Construction provides strong resistance to static electricity by having no soldered terminals. • Matrix adhesive used to create highly dust-proof construction with good ventilation. • Lower profile, lighter weight, and crisp clicking action. • Omron's unique circular contact action ensures a high level of resistance to foreign matter. • RoHS Compliant. Application Examples Use Dome Keys for the operating parts on various electronic devices that require low-profile controls, as follows: • Operating switches with few mounted parts above PCBs. (Example: Camera operating buttons) • Small orders, where initial investment in Dome Arrays is not feasible. (Example: Trial applications, commercial equipment, etc.) • Applications requiring a single key only. (Example: Reset buttons) B3D-5112 2 -411 B3D Specifications Item Model B3D-4112 B3D-5112 Diameter of contact dome 4-mm dia. 5-mm dia. Operating force (OF) approx. 170 ± 50 gf (1.67± 0.49 N) Releasing force (RF) 20 gf min. (0.2 N min.) Pretravel (PT) 0.2 ± 0.1 mm Height 0.3 ± 0.1 mm Life expectancy 500,000 operations min. Switching capacity 10 mA at 12 VDC (resistive) Minimum permissible load 1 mA at 3 VDC (resistive) Ambient operating temperature -40 to 80°C (at 60% RH max.) with no icing or condensation. Ambient storage humidity 10% to 90% (at 40°C max.) Contact - base material Stainless steel Plating Silver 1,000,000 operations min. Note: The Dome Keys are sold in units of 500 (20 sheets, with 25 Dome Keys per sheet). Orders must be made in multiples of 500 Dome Keys. Ultra-low Profile Dome Key B3D 269 Structure ■ Circular Contact PET film (white) (with matrix adhesive) Stainless steel contact dome (circular contact) Polyurethane rubber film (with adhesive) When contact dome keys are attached to the PCB, any PCB dust or foreign particles will tend to collect in the center of the key when it is pressed. Therefore, poor contact occurs easily in keys that provide contact at the center point only. The circular contact construction provides contact along the circumference of a circle, thus preventing poor contact by avoiding the center point. Contact dome resistant to foreign matter (circular contact) Conventional models ■ Matrix Adhesive The surface structure of this adhesive has grid-shaped slits, as shown in the following cross-sectional diagram. These slits provide both ventilation and dust-proofing, which is required for contact dome operation. Cylindrical protrusion Cover film 15 µm Matrix (acrylic) adhesive: 25 µm Slits Contact at center point Contact along circle circumference (circular contact) Recommended Contact Form 4 mm Diameter Contact Dome (B3D-4112) 5 mm Diameter Contact Dome (B3D-5112) 6.2 dia. 5.2 dia. 1.8 dia. Gold-plated nickel 2.3 dia. 0.4 0.4 1.2 2.0 Single-side PCB 2.8 dia. Resist (30 to 50 µm) 3.8 dia. Resist (30 to 50 µm) 6.2 dia. Gold-plated nickel Multilayer PCB 2.3 dia. Multilayer PCB 2.8 dia. 270 1.2 2.0 Single-side PCB 5.2 dia. 1.8 dia. Gold-plated nickel Ultra-low Profile Dome Key 3.8 dia. B3D Gold-plated nickel Recommended Operating Part Form 4 mm Diameter Contact Dome (B3D-4112) 5 mm Diameter Contact Dome (B3D-5112) Resin Resin 1 dia. Entire circumference: R 0.2 1.5 dia. Entire circumference: R 0.2 Dimensions B3D-4112 Section A enlarged Section A (54) 25, 7.4 dia. 0.3 0.3 10 10 (54) 10 10 10 10 10 10 B3D-5112 Section A (54) 25, 8.4 dia. Section A enlarged 0.3 0.3 10 10 (54) 10 10 10 10 10 10 Ultra-low Profile Dome Key B3D 271 PCB Pattern Diagrams B3D-4112 B3D-5112 Precautions ■ Attaching to the PCB ■ Reflow Soldering Remove the Dome Key from the sheet using tweezers or a vacuum pick-up tool, and attach it above the contact on the PCB surface, which has been wiped clean in advance. Press down on the top surface using an elastic material, such as urethane rubber, and a force of 2.94 to 4.9 N. Place a positioning mark (circle) on the PCB for easy positioning. The Dome Key cannot withstand heat from reflow soldering. Always perform reflow soldering before attaching the Dome Key to the PCB. Make sure that the position of the Dome Key is aligned correctly before use. Significant misalignment may result in short-circuits or reduced sensitivity. Note: The recommended vacuum pick-up tool is the Hozan P-835 Vacuum Pick with an M suction pad (7-mm dia.). Do not reuse a B3D Dome Key that has been detached from the PCB. Attach a new Dome Key to the PCB. Do not touch the contact dome with bare hands, or with unclean gloves. Doing so may damage the contact dome, which is the part that comes in contact with the PCB. 272 Ultra-low Profile Dome Key B3D ■ Washing Do not wash the Dome Key. The Dome Key is not water-resistant and must not be exposed to water or other liquids. ■ Common Precautions Be sure to read the precautions common to all Tactile Switches, contained in the Technical User’s Guide, “Tactile Switches, Technical Information” for correct use. MEMO Ultra-low Profile Dome Key B3D All sales are subject to Omron Electronic Components LLC standard terms and conditions of sale, which can be found at http://www.components.omron.com/components/web/webfiles.nsf/sales_terms.html ALL DIMENSIONS SHOWN ARE IN MILLIMETERS. To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527. OMRON ON-LINE OMRON ELECTRONIC COMPONENTS LLC Global - http://www.omron.com USA - http://www.components.omron.com 55 E. Commerce Drive, Suite B Schaumburg, IL 60173 847-882-2288 Cat. No. X303-E-1 11/10 Ultra-low Profile Dome Key Specifications subject to change without notice B3D Printed in USA