Tactile Switch 3x4x2mm 4 Pins SMD Micro Push Button

Specifications

• Switch Type: Tactile Push Button Switch

• Mounting Type: Surface Mount Device (SMD / SMT)

• Actuation Direction: Top-Actuated (Contoured Raised Button)

• Circuit / Contact Form: Single Pole Single Throw - Normally Open (SPST-NO)

• Dimensions (L × W × H): 4.0mm × 3.0mm × 2.0mm [Estimated]

• Contact Rating: 50mA @ 12V DC Max

• Contact Resistance: 100mΩ Max

• Insulation Resistance: 100MΩ Min @ 100V DC

• Dielectric Withstanding Voltage: 250V AC for 1 minute

• Operating Force: 180gf ± 50gf

• Travel / Stroke: 0.20mm ± 0.05mm

• Operating Life: 50,000 to 100,000 cycles

• Terminal Configuration: 4-Pin Gull-Wing SMD / SMT Solder Leads

• Housing Material: High-Temperature Thermoplastic with Stainless Steel Cover

• Operating Temperature: -20°C to +70°C

• Compatible Platforms: Custom Microcontroller PCBs, Wearables, Key Fobs, Handheld Gadgets

 Project Evolution

Unlock New Capabilities

• Past Projects (Prerequisites)
  If you've already experimented with standard 6x6mm through-hole tactile buttons on breadboards or larger 4x4mm SMD switches, you are familiar with digital GPIO sensing, internal pull-up configuration, and software debounce routines. Stepping up to this sub-miniature 3x4x2mm 4-pin gull-wing SMD tactile switch is the natural next step toward transitioning bulky benchtop prototypes into sleek, low-profile surface-mount printed circuit boards
• Feature Upgrade (What This Unlocks)
  This 3x4x2mm tactile switch unlocks ultra-compact top-actuated switching inside tight device enclosures. Featuring a low 2.0mm profile height, a rigid stainless steel protective cover, and a contoured black actuator for positive finger engagement, it enables dependable reset, power, and navigation buttons in wearable devices, automotive key fobs, compact remote controllers, and miniaturized IoT sensor nodes where vertical board clearance is heavily constrained

Effort Level & Minimum Hardware

Effort Level: Intermediate 

Minimum hardware to get started:

• Custom PCB with SMT Solder Pads or SMD Breakout Board — required because this switch utilizes sub-miniature 3.0×4.0mm gull-wing surface-mount leads that cannot plug directly into standard 2.54mm pitch breadboards or perfboards.
  
• Fine-Tip Temperature-Controlled Soldering Station & Thin Solder Wire (0.3mm–0.5mm) — required to form reliable solder fillets on the 4 tiny leads without creating solder bridges or overheating the internal contact dome.
  
• Microcontroller Development Board (Arduino Uno, ESP32, or RP2040) — required to provide the digital logic pull-up voltage and detect button state transitions in firmware

Virtual Technician & Pinout Guide

⚠️ Safety Warnings:

• Soldering Thermal Limits: Do not exceed 260°C for more than 5 seconds during hand or reflow soldering; excessive thermal exposure will melt the internal thermoplastic housing and permanently ruin the tactile snap dome.
  
• Pin Pairing Verification: The 4 gull-wing leads are internally connected in two pairs across the SPST-NO contact; always verify terminal continuity with a multimeter before soldering to avoid bridging your GPIO line straight to ground.
  
• Floating Input Prevention: Always configure the microcontroller GPIO pin with an internal pull-up resistor (or install an external 10kΩ pull-up resistor); leaving the input pin floating will cause random false triggers from environmental noise

Package Includes: 

1× Tactile Switch 3x4x2mm 4 Pins SMD Micro Push Button

Frequently Asked Questions

1. Which KiCad or EasyEDA footprint matches a 3x4x2mm 4-pin SMD tactile switch?
   A 3x4x2mm 4-pin gull-wing tactile switch is not pad-compatible with 4x4mm or 6x6mm footprints, and KiCad does not list a generic "3x4mm" name, so use KiCad's Button_Switch_SMD:SW_SPST_PTS810 footprintwhich fit the 3.2×4.2mm to 3.4×4.2mm body dimensions out of the box.
2. Will a 2.0mm tall 3x4x2mm SMD tactile switch fit under stacked Arduino/ESP32 shields or protrude through a case wall?
   At 2.0mm total height (roughly a 1.4–1.5mm body housing with a 0.5–0.6mm contoured actuator protrusion), this 3x4x2mm SMD tactile switch sits low enough to prevent accidental presses under stacked shields and inside recessed case holes, though you will need an external plunger or living-hinge button for it to reach through a standard enclosure wall.
3. Can I mount a 3x4x2mm 4-pin SMD tactile switch onto a standard breakout adapter or perfboard for breadboard prototyping?
   While a 3x4x2mm 4-pin SMD tactile switch will not fit a standard SOT-23 breakout adapter, it drops cleanly onto a standard SOIC-8 (1.27mm pitch) breakout board by skipping the middle pads—and even bridges a 2×2 grid of standard 2.54mm (0.1") perfboard without needing an adapter at all.
4. What happens if I wire a 3x4x2mm SMD tactile switch directly to a 24V PLC input or a 5V relay coil?
   Both loads will prematurely destroy the 3x4x2mm tactile switch through micro-arcing and contact welding: a 24V PLC input exceeds the dome's DC arc-sustaining voltage threshold, while an un-snubbed 5V relay coil generates a high-voltage inductive kickback spike ($V = -L \frac{di}{dt}$) across the microscopic ~0.2mm contact air gap.
5. Is an ESP32 or STM32 internal pull-up resistor strong enough for a 3x4x2mm SMD tactile switch?
   Relying solely on a ~45kΩ microcontroller internal pull-up (~73µA at 3.3V) is a common cause of intermittent or missed presses after 6–18 months on miniature 3x4x2mm tactile switches, so adding an external 4.7kΩ to 10kΩ pull-up resistor is strongly recommended—even on battery-powered ESP32 and STM32 designs.
6. Which two pins are internally connected on a 3x4x2mm 4-pin SMD tactile switch, and can I route a trace underneath it?
   On a 3x4x2mm 4-pin SMD tactile switch, the two pins protruding from the same 4mm long side (spaced ~2.15mm apart) are internally shorted together while the momentary contact closes across the 3mm short width, and you can safely route a low-voltage signal trace directly underneath the black thermoplastic body on a 2-layer PCB as long as standard solder mask covers the trace.
7. Does orientation matter when placing a 3x4x2mm 4-pin SMD tactile switch on a PCB, and what RC debounce values should I use?
   A technician can mount the 3x4x2mm 4-pin SMD tactile switch rotated 180° with zero change to circuit behavior, and for an interrupt-driven GPIO pin, a two-resistor, one-capacitor filter ($R_1 = 10\text{k}\Omega$, $R_2 = 10\text{k}\Omega$, $C = 220\text{nF}$) cleanly suppresses mechanical bounce without pitting the tiny dome contacts.
8. What firmware debounce time (in milliseconds) should I set for a 3x4x2mm SMD tactile switch in Bounce2 or MicroPython?
   Set your firmware debounce window to 15ms–20ms (with 20ms as the safest default) for this 3x4x2mm metal-dome switch; while fresh straight-down presses settle in 1–5ms, hesitant finger lifts and high-cycle domes produce 8–12ms chatter bursts, whereas staying at or below 20ms keeps rapid double-taps (~120–150ms apart) feeling completely instantaneous.
9. Can I wire a 3x4x2mm SMD tactile switch as a general-purpose User Button on ESP32 GPIO0 or STM32 BOOT0?
   Avoid wiring general-purpose User Buttons to strapping pins on ESP32 or STM32 boards, and reserve GPIO0 (ESP32/S3) or BOOT0 (STM32) strictly for a dedicated recovery/flashing button so accidental button presses or external pull resistors do not trap the microcontroller in flash download mode at power-up.
10. Why did my 3x4x2mm SMD tactile switch lose its tactile click or stop registering presses after soldering?
    A mushy or "dead" click after soldering happens when excessive heat warps the black thermoplastic housing or heat-staked top cover by just 0.05–0.15mm—collapsing the ~0.20mm metal dome pre-load arch—while liquid flux wicking into the unsealed cavity insulates the contacts electrically before extreme heat melts the actuator into a permanent short.
11. How do I tell if an intermittent 3x4x2mm SMD tactile switch has a cold solder joint or fouled internal contacts, and how do I fix it?
    Probe directly on the exposed metal shoulders of the gull-wing leads rather than the PCB pads to bypass the solder joints in under 30 seconds; if the shoulder reading works cleanly, reflow the joint using rosin-core solder wire on the outer pad shelf and avoid flooding the switch with liquid or gel flux, which wicks up the leads into the unsealed IP40 cavity.
12. Why do 3x4x2mm 4-pin SMD tactile switches skew sideways during hot-air or reflow oven assembly?
    While vertical tombstoning is rare due to the four-lead stance, rotational skewing (yawing) and one-sided floating happen frequently during batch reflow because the 3x4x2mm switch weighs only ~0.04g, allowing uneven solder paste volume or pad thermal mass to pull the lightweight body off-axis.
13. Does Probots supply 3x4x2mm 4-pin SMD tactile switches in cut-tape strips for pick-and-place assembly or loose bags?
    Standard online retail orders at Probots ship in ESD-safe zip-lock bags with no minimum order quantity (MOQ = 1 piece) and automatic tiered bulk pricing starting at 5–10+ units, while contract manufacturers needing continuous cut-tape strips for pick-and-place feeders can request reel/cut-tape packaging directly through the Probots B2B desk.
14. Why source 50–500 units of 3x4x2mm SMD tactile switches from Probots instead of mixed surplus lots?
    Ordering 50–500 units from a single traceable production lot at Probots—rather than mixed surplus or liquidation grab-bags—protects small-batch PCBA runs from inconsistent actuation forces, lead-free reflow housing warp, pad-span drift, and oxidized gull-wing leads.
15. When should I choose this 3x4x2mm SMD tactile switch over Probots' 4x4x1.5mm SMD (PRO3783) or 6x6mm through-hole (PRO055) switches? Choose this 3x4x2mm 4-pin gull-wing SMD switch over Probots' 4x4x1.5mm SMD (PRO3783) or 6x6mm through-hole (PRO055) switches when you want to eliminate secondary through-hole soldering on SMD boards, reclaim bottom-layer PCB real estate, fit narrow X-axis board edges, or gain 0.5mm of extra actuator reach over ultra-flat 1.5mm switches.