2 Pin SMD Normal Close Tactile Switch 4x6x2.5
Normal Close Tactile Switch 4x6x2.5 is a surface‑mount momentary switch designed for circuits that require a default‑closed signal path. Unlike standard normally‑open tact switches, this component holds the contact closed until the actuator is pressed, then breaks the circuit. Available in a 4.0×6.0×2.5 mm footprint, it provides a fail‑safe, space‑saving interface for security loops, hardware reset lines, presence detection, and any application where an active-low trigger is more reliable than a held‑open state.
Normally Closed Tactile Push Button – Product Overview
When a design demands a circuit that is complete by default, the normally closed tactile push button becomes the preferred choice. The Normal Close Tactile Switch 4x6x2.5 is built around a precision dome contact that, at rest, bridges the two terminals of each pole. Pressing the actuator lifts the dome, breaking the connection until the button is released. This inverted logic reduces component count in pull‑up/down networks and creates a fail‑safe condition – if the switch is damaged or the button cap is lost, the system defaults to the closed state, which can be used to trigger alarms, hold processors in reset, or maintain enable signals.
Physically, the switch uses a 4‑pin gull‑wing SMD footprint that measures just 4.0 mm wide by 6.0 mm long, with a board‑to‑top height of 2.5 mm. This compact envelope fits easily alongside 0603 passives and QFP ICs, making it practical for dense portable devices, sensor nodes, and edge computing hardware. Its four terminals provide strong mechanical anchoring despite the small size; two pins are internally connected to the fixed contact and two to the moving dome, giving double solder joints for each electrical node. For a deeper understanding of contact terminology and logic, you can read All About Circuits’ guide on switch contact design.
The switch is supplied in tape‑and‑reel packaging for high‑speed pick‑and‑place assembly, and its sealed housing resists flux ingress during reflow soldering. Whether you are designing an industrial control panel that must assert an alarm when a cover is removed, or a consumer device that uses a normally‑closed sense line to detect a closed lid, this SMD normally closed switch 4x6mm delivers a reliable, maintenance‑free switching solution.
SMD Normally Closed Switch 4x6mm Specifications
| Parameter | Specification |
|---|---|
| Product Name | Normal Close Tactile Switch 4x6x2.5 |
| Part Number | TS-4601 |
| Switch Configuration | SPST – Normally Closed (NC) |
| Contact State at Rest | Closed (circuit complete) |
| Contact State When Pressed | Open (circuit broken) |
| Number of Terminals | 4 (2 pairs connected internally) |
| Mounting Type | Surface Mount (SMD/SMT), gull‑wing leads |
| Footprint (L × W) | 6.0 mm × 4.0 mm |
| Height Above PCB | 2.5 mm |
| Actuator Type | Square / rectangular button |
| Operating Force | 220 gf ±40 gf (typical) |
| Travel | 0.25 mm ±0.1 mm |
| Contact Rating | 12 V DC, 50 mA |
| Contact Resistance (initial) | ≤ 100 mΩ |
| Insulation Resistance | ≥ 100 MΩ at 100 V DC |
| Dielectric Strength | 250 V AC for 1 minute |
| Bounce Time | ≤ 5 ms (typical) |
| Mechanical Life | ≥ 50,000 cycles |
| Terminal Plating | Copper alloy, gold‑plated (Au over Ni) |
| Housing Material | LCP / Nylon 66, UL94 V‑0 |
| Sealing | Washable / IP50 (dust resistant) |
| Soldering Profile | Lead‑free reflow, peak 260 °C |
| Operating Temperature | -25 °C to +85 °C |
| Packaging | Tape & Reel (2,000 pcs/reel standard) |
Why Engineers Choose This 4‑Pin NC Tactile Switch
Inherent Fail‑Safe Contact State
Because the 4‑pin NC tactile switch rests in a closed position, any physical damage or actuator loss drives the output to the safe condition (loop closed). This makes it ideal for tamper‑evident and emergency‑stop circuitry where a broken wire must be detected immediately.
Ultra‑Compact 4.0×6.0 mm Body
Occupies minimal board space and aligns with industry‑standard SMD pad layouts. The low 2.5 mm profile allows placement under displays, batteries, or shielding cans without mechanical interference.
Active‑Low Interface Without Pull‑Ups
In microcontroller input circuits, the normally‑closed state holds the GPIO pin LOW (or HIGH with a single external resistor) and goes to the opposite state only during a press – eliminating the need for continuous pull‑up/down bias networks.
Robust Dome with Definite Click
A stainless‑steel dome delivers a crisp tactile snap and a clear open‑circuit transition. The relatively high 220 gf actuation force prevents accidental triggering from vibration or light touches.
Sealed Construction for Process Reliability
The sealed body withstands standard water‑wash PCB cleaning and keeps flux, dust, and moisture away from the dome. This ensures consistent contact performance even after multiple thermal cycles.
Tape‑&‑Reel Packaging for Automation
Supplied in industry‑standard 16 mm tape, compatible with all major pick‑and‑place machines. The symmetrical 4‑pad footprint simplifies solder paste printing and visual inspection.
Applications of PCB Momentary Normally Closed Switch
Normal Close Tactile Switch 4x6x2.5 – Frequently Asked Questions
How does a normally closed tactile switch differ from a standard normally open one?
Can I use this 4‑pin NC switch in a standard 4‑pin tactile footprint?
Is the switch sealed against dust and moisture?
What is the typical bounce behaviour of an NC tactile switch?
Can I order this SMD normally closed switch 4x6mm in small quantities for prototyping?
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