2 Pin SMD Normal Close Tactile Switch 4x6x2.5

Name: 2 Pin SMD Normal Close Tactile Switch 4x6x2.5
Brand: Vistar Electronics
SKU: TS-4601
Availability: InStock

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.

Product NameNormal Close Tactile Switch 4x6x2.5

Part NumberTS-4601

Switch ConfigurationSPST – Normally Closed (NC)

Contact State at RestClosed (circuit complete)

Contact State When PressedOpen (circuit broken)

Overview

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.

Technical Specifications

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

Applications of PCB Momentary Normally Closed Switch

🏠 Security & Alarm Systems Magnetic door sensors, tamper loops, and panel cover switches use a PCB momentary normally closed switch to keep the alarm loop complete; opening the door or pressing the switch breaks the circuit and triggers an alert.

🖥 Processor Reset & Boot Select A normally‑closed tactile button holds a RESET or BOOT line at its active level, then releases it when pressed – ideal for recovering from firmware hangs without adding open‑drain logic.

🧪 Test & Measurement Gear Signal‑path interrupt buttons that let an engineer “break” a connection while probing. The NC default lets the instrument operate normally until the button is intentionally pressed.

🎮 Consumer & Gaming Peripherals Back‑cover detection in handhelds, trigger guard switches in controllers, and presence‑sensing in VR headsets that rely on a default‑closed loop to know the device is assembled or worn.

🏭 Industrial Safety & E‑Stops Auxiliary NC contacts in portable pendants and limit switches. When used with a Normal Close Tactile Switch 4x6x2.5, the safety chain remains closed, and any press stops the machine.

🌐 IoT Sensor Nodes Battery‑powered devices that monitor a lid or enclosure state without consuming current for pull‑ups; the NC switch holds the sense line at a known level and only changes state during rare tamper events.

Normal Close Tactile Switch 4x6x2.5 – Frequently Asked Questions

How does a normally closed tactile switch differ from a standard normally open one?

A standard tactile switch is open at rest and closes when pressed. The Normal Close Tactile Switch 4x6x2.5 is the opposite: it completes the circuit at rest and breaks it when you press. This inverted behavior simplifies fail‑safe and alarm circuits, where a broken connection is the trigger event.

Can I use this 4‑pin NC switch in a standard 4‑pin tactile footprint?

Physically the 4.0×6.0 mm outline and pad spacing often match common 4‑pin SMD tactile footprints, but always check the pinout. In a 4-pin NC tactile switch, the two pins on each side are still internally connected, but the default state is closed. Ensure your PCB traces reflect this, especially if you are retrofitting a design originally laid out for a normally‑open part.

Is the switch sealed against dust and moisture?

Yes, this normally closed tactile push button has a sealed housing that meets IP50 dust‑resistance standards and survives board washing. It is not rated for full immersion (IP67), so for outdoor applications an additional enclosure boot or conformal coating is recommended.

What is the typical bounce behaviour of an NC tactile switch?

When the button is pressed, the dome moves away from the fixed contact, generating a short bounce period (typically ≤5 ms). The signal will transition from LOW to HIGH (depending on circuit) and may show a few bounces before settling open. A simple debounce routine in firmware or a capacitor on the input pin is recommended for reliable edge detection.

Can I order this SMD normally closed switch 4x6mm in small quantities for prototyping?

Absolutely. Cut‑tape samples and prototyping reels are available. For production volumes, we offer full reels (typically 2,000 pieces) with competitive pricing and lead times. Visit the product page or contact our sales team for current stock and a detailed datasheet.

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