English
The 12*12*3mm SMD Piezoelectric Passive Buzzer is a surface‑mount passive piezoelectric buzzer that accepts a wide 1–25 V drive signal, allowing a single component to cover everything from 3.3 V logic rails up to 24 V industrial buses. Its resonant frequency is centred at 4000 Hz, and at the rated 3 V the current draw stays below 5 mA, making it practical for battery‑powered instruments as well as fixed installations. With a 12 mm square footprint and a height of only 3 mm, the buzzer fits into dense PCB assemblies where space and power are both tightly managed.
Because the 12*12*3mm SMD Piezoelectric Passive Buzzer is a passive transducer, it requires an external AC waveform, typically a square wave or PWM signal at or near 4000 Hz. This gives the firmware complete control over the sound character: on‑off timing, frequency modulation and multi‑tone patterns can all be defined in software without changing any hardware. The wide supply tolerance means the same buzzer can be used across product variants with different rail voltages, simplifying procurement and qualification.
The 4000 Hz centre frequency sits within the 2–5 kHz band where the human ear has greatest sensitivity, so alerts remain clearly audible even at modest drive levels. At 3 V peak‑to‑peak the guaranteed minimum sound pressure is 80 dB at 10 cm, and sample measurements typically exceed 83 dB. The capacitive nature of the piezoelectric element eliminates magnetic emissions, which is an advantage when the buzzer is placed near sensitive analogue or RF circuitry.
| Parameter | Value | Test Conditions |
| Product Type | Piezoelectric Passive Buzzer | — |
| Rated Voltage | 3 V (Vp‑p) | Peak‑to‑peak reference |
| Operating Voltage | 1 – 25 V (Vp‑p) | Full functional range |
| Resonant Frequency | 4000 ± 300 Hz | At rated voltage |
| Sound Output at 10 cm | ≥ 80 dB | At 3 V, 4000 Hz |
| Operating Current | ≤ 5 mA | At 3 V |
| Capacitance | 14,000 ± 30% pF | At 1 kHz, 25 ℃ |
| Operating Temperature | -30 ℃ ~ +70 ℃ | Continuous |
| Storage Temperature | -40 ℃ ~ +85 ℃ | Non‑operating |
| Dimensions (L × W × H) | 12.0 × 12.0 × 3.0 mm | Body only |
| Weight | 0.4 g | Typical |
| Housing Material | Black LCP | Reflow compatible |
| Mounting Type | SMD | Reflow: 255 ± 5 ℃, up to 3 passes |
Consumer appliance interfaces: end‑of‑cycle and fault alerts in washing machines, microwave ovens and air purifiers, where a single buzzer can serve 5 V and 12 V control boards without voltage translation.
Smart home panels and IoT gateways: status tones for Wi‑Fi pairing, security arming and voice assistant acknowledgement, driven directly from a 3.3 V GPIO.
Commercial refrigeration and HVAC equipment: door‑ajar and temperature‑threshold alarms in display cases and walk‑in coolers, benefiting from the extended operating temperature range.
Battery‑powered portable instruments: handheld meters and environmental monitors where the sub‑5 mA current draw extends run time.
Automotive aftermarket accessories: 12 V direct drive for seatbelt reminders, parking sensor feedback and charging indicators.
| Design Requirement | MLT‑1230 Attribute |
| One buzzer for multiple product voltages | 1–25 V range covers 3.3 V, 5 V, 12 V and 24 V rails, consolidating inventory and simplifying BOM management. |
| Low energy consumption | ≤5 mA at 3 V is suitable for battery and energy‑harvesting systems; actual consumption depends on drive voltage and duty cycle. |
| Clear alert for all age groups | 4 kHz resonance is consistently perceptible across demographics, and the tone carries well through typical plastic enclosures. |
| EMC‑friendly placement | No magnetic field or inductive switching noise, so the buzzer can be placed near antennas, sensors or precision analogue circuits. |
| Slim enclosure integration | 3 mm height fits beneath displays, battery packs and shielding cans in portable and panel‑mounted products. |
The 14000 pF capacitance represents a reactive load of approximately 2.8 kΩ at 4000 Hz. Most 3.3 V MCU outputs can drive this directly, but for 12 V or 24 V operation a simple transistor buffer or dedicated piezo driver is recommended to manage the higher voltage swing. Reference schematics are available from MEIDI’s application team.
MEIDI Intelligent Technology has been designing and manufacturing acoustic components since 2011. The company’s vertically integrated factory in Jiangsu, China, covers LCP moulding, automated SMD assembly, piezoelectric ceramic processing and 100 % end‑of‑line acoustic testing. ISO 9001 certification and a dedicated reliability laboratory provide the framework for consistent quality at high volumes.
The 12*12*3mm SMD Piezoelectric Passive Buzzer is produced on the same automated lines that supply MEIDI’s automotive and industrial customers. Every production batch is subjected to a comprehensive suite of tests. Resonant frequency is verified on 100 % of units to ensure the 4000 ± 300 Hz window is met; production samples consistently show a tight 4000 Hz distribution. Capacitance is screened to 14000 pF ±30 %, and sound pressure level is confirmed through statistical sampling, with typical values ranging from 83.8 dB to 86.7 dB. Environmental stress screening includes 48 hours at +80 °C, 48 hours at -30 °C, and five thermal shock cycles. Mechanical robustness is validated by vibration testing and 75 cm drop tests, while soldering integrity is verified by solder heat resistance and full reflow profiling. All test records are linked to a lot code on the housing and are retained for ten years.
1. How does the wide voltage range affect the drive circuit?
At 3 V many microcontrollers can drive the buzzer directly because the current draw is below 5 mA. As the supply voltage increases, the peak current also rises; at 12 V or 24 V a simple transistor buffer or logic‑level MOSFET is advisable. The important advantage is that the same buzzer can be used across all these voltages, eliminating the need for different part numbers.
2. Why is the resonant frequency set at 4000 Hz?
4000 Hz lies within the 2–5 kHz range where human hearing is most sensitive, so the tone is easily detected even at low volumes. This frequency also propagates well through plastic enclosures and is less directional than higher frequencies, making it a good general‑purpose alert tone.
3. Can the MLT‑1230 produce voice or music?
No. The device is a narrowband resonant transducer optimised for 4000 Hz. While simple patterns such as beeps and chirps can be generated by varying the PWM duty cycle, it cannot reproduce speech or complex audio. For such applications a dynamic speaker or wideband piezo sounder should be considered.
4. What does the 14000 pF capacitance mean for my design?
The capacitance defines the reactive load seen by the driver. At 4000 Hz the reactance is about 2.8 kΩ. This value should be used to calculate the peak current the driver must supply. The ±30 % tolerance should be accounted for in worst‑case design margins.
5. Is customisation available?
Yes. MEIDI offers custom frequency tuning within a 2–5 kHz range, alternative capacitance values, and different tape‑and‑reel configurations for high‑volume OEM projects. Contact the applications team with your requirements for a feasibility assessment and lead time.
For datasheets, voltage‑specific acoustic curves, drive circuit reference designs or OEM customisation, submit your requirements through the contact form. MEIDI application engineers normally respond within one business day with technical documentation and volume pricing.
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