English
The 5*5*2mm Surface Mount Magnetic Passive Buzzer is a surface‑mount electromagnetic passive buzzer that combines a compact 5.0 × 5.0 mm footprint with a centre‑hole acoustic port. This symmetrical opening helps radiate sound more evenly around the component, making the perceived loudness less dependent on the orientation of the end device. The electrical characteristics are identical to those of the offset‑hole MLT‑5020: a 12 Ω coil that can be driven directly from many 3.3 V microcontroller pins, a rated voltage of 3.0 V and a resonant frequency of 4000 Hz. With a height of 2.0 mm and a mass of 0.1 g, the part is compatible with standard pick‑and‑place equipment and reflow soldering.
The choice between centre‑hole and offset‑hole configurations is primarily an acoustic one. When the buzzer is mounted behind a grille that is aligned with the centre of the component, or when the device may be used in multiple orientations, the symmetrical emission pattern of the MLT‑5020H can provide a more consistent alert. MEIDI manufactures both variants on the same automated production lines, with identical reliability testing and traceability, so the decision can be based purely on the sound‑field requirements of the application.
As a passive electromagnetic transducer, the 5*5*2mm Surface Mount Magnetic Passive Buzzer needs an external AC signal to generate sound. A 4000 Hz square wave with a 50 % duty cycle at the rated voltage will produce the specified output. The 12 Ω coil resistance means that many 3.3 V microcontrollers can drive the buzzer without a separate transistor, though a simple NPN buffer remains a safe option when the GPIO current capability is not guaranteed. The 2 V to 4 V operating window covers single‑cell lithium batteries, coin cells and regulated logic supplies.
The centre‑hole opening is located at the geometric centre of the housing. This arrangement tends to produce a more uniform sound field in the forward hemisphere compared to an offset port, where the level can drop noticeably when the listener is positioned away from the hole axis. For a handheld scanner, a wearable monitor or a wall‑mounted panel that may be approached from different angles, this characteristic can be a useful differentiator. The guaranteed minimum sound pressure is 80 dB at 10 cm, and production measurements on sample batches typically show values in the mid‑80 dB range.
The buzzer is delivered on 330 mm reels with 2500 pieces per reel, ready for high‑speed SMT placement. The black LCP body has been proven to withstand multiple reflow cycles and the thermal and mechanical stresses described in the reliability section below.
The sound port is positioned in the centre of the housing so that the acoustic output is less affected by the mounting orientation, which is helpful when the final device may be held or installed in various positions.
A coil resistance of 12 Ω allows the buzzer to be connected directly to a 3.3 V GPIO pin that can source up to 100 mA, removing the need for an external driver transistor in many designs.
The operating voltage range of 2 V to 4 V provides compatibility with lithium‑ion cells, coin cells and standard 3.3 V rails without extra regulation.
At 5.0 mm square and 2.0 mm high, the package fits within the same PCB area as many other miniature SMD buzzers, while delivering a rated sound pressure of at least 80 dB.
The resonant frequency is specified at 4000 Hz with a tolerance of ±300 Hz, placing the tone in the most sensitive region of human hearing.
The black LCP housing is designed for lead‑free reflow soldering and can endure the thermal profile of double‑sided PCB assembly.
Tape‑and‑reel packaging with 2500 units per reel supports automated placement and minimises changeover time on high‑volume lines.
| Parameter | Value |
| Product Type | Electromagnetic SMD Passive Buzzer |
| Rated Voltage | 3.0 V (o‑p) |
| Operating Voltage | 2 – 4 V (o‑p) |
| Sound Output at 10 cm | ≥ 80 dB |
| Operating Current | ≤ 100 mA |
| Resonant Frequency | 4000 ± 300 Hz |
| Coil Resistance | 12 ± 3 Ω |
| Operating Temperature | -20 °C ~ +70 °C |
| Storage Temperature | -30 °C ~ +80 °C |
| Dimensions (L × W × H) | 5.0 × 5.0 × 2.0 mm |
| Weight | 0.1 g |
| Housing Material | Black LCP |
| Packaging | Tape & Reel; 2500 pcs per 330 mm reel |
| Soldering Method (Recommended) | Reflow: 255 ± 5 °C, 3 s; Preheat 180 °C, 40–70 s |
The application suggestions that follow are derived from the component’s electrical and mechanical specifications. They are not a substitute for end‑product validation against the relevant standards.
Handheld industrial terminals such as barcode scanners and RFID readers, where the device is often rotated during use and the buzzer must remain audible regardless of orientation.
Medical wearables and portable diagnostic tools that need a compact alert source with predictable sound distribution, including insulin pumps, patient monitors and ambulatory recorders.
Smart home panels and wall‑mounted controllers whose front‑facing grille aligns naturally with the centre‑hole emission pattern, giving a balanced alert across the room.
Automotive cabin electronics, including seat‑belt reminders and door‑ajar chimes, where the buzzer may be placed behind a small aperture and the symmetrical output helps maintain consistent volume.
IoT gateway nodes and sensor hubs that require an audible status indicator in a very small footprint; the 2 V to 4 V supply range matches common battery and energy‑harvesting power architectures.
Consumer accessories such as power banks, Bluetooth trackers and charging cases, where the buzzer provides power‑on and low‑battery alerts in a space‑constrained plastic enclosure.
The 5*5*2mm Surface Mount Magnetic Passive Buzzer is essentially the MLT‑5020 with a different acoustic port geometry. Electrically and mechanically, the two parts are interchangeable. The benefit of the centre‑hole design is a more uniform radiation pattern: in testing, the sound pressure level varies less with the angle between the buzzer and the measurement microphone. This can be an advantage when the device does not have a fixed listening position, or when multiple users need to hear the alert from different directions.
The 5.0 mm square footprint and 2.0 mm height make the MLT‑5020H a practical choice for space‑limited PCBs. The 12 Ω coil keeps the drive requirements simple, and the LCP housing has been qualified through the full reliability programme detailed below. For projects that are already using the MLT‑5020 but want to evaluate the acoustic effect of a centre port, the change can be made with no board redesign.
MEIDI Intelligent Technology has been producing electromagnetic and piezoelectric acoustic components since 2011. The company operates a vertically integrated facility in Jiangsu, China, covering LCP moulding, precision coil winding, SMD assembly and inline acoustic testing. ISO 9001 certification and a dedicated reliability laboratory provide the framework for consistent quality, and batch‑level traceability is maintained for all shipments.
The MLT‑5020H is manufactured on the same automated lines that supply MEIDI’s automotive and industrial customers. Each production batch is subjected to the reliability verification programme prescribed in the product specification. Climatic stress screening includes 48 hours at +80 °C, 48 hours at −30 °C, and five thermal shock cycles between these extremes with a 30‑minute dwell. Mechanical endurance is checked by sweeping vibration from 10 Hz to 55 Hz at 1.0 mm amplitude on all three axes, and by three 75 cm drops onto a hardwood surface. Humidity resistance is confirmed by a 48‑hour exposure to 50 °C and 90–95 % relative humidity, followed by a 2‑hour recovery. Soldering integrity is verified through a 250 °C solder heat test and full reflow profile validation.
Production sample measurements for the MLT‑5020H typically show sound pressure between 84.5 dB and 87.5 dB, with current values between 85.4 mA and 88.1 mA. These figures are representative of standard production and are documented in the batch test reports available to customers. The guaranteed limits remain at 80 dB minimum and 100 mA maximum.
1. How does the MLT‑5020H differ from the MLT‑5020?
The only difference is the position of the sound outlet. The MLT‑5020H has a centre‑hole, while the MLT‑5020 has an offset hole. All electrical parameters, dimensions and soldering characteristics are the same. The choice depends on whether a symmetrical radiation pattern is beneficial for the application.
2. Can this buzzer be placed by standard pick‑and‑place machines?
Yes. It is supplied in tape‑and‑reel format with 2500 pieces per 330 mm reel. The flat top surface and 5.0 mm square body are well suited to standard SMT nozzles and vision alignment systems.
3. What drive signal is recommended?
A 4000 Hz square wave at 3.0 V peak‑to‑peak, 50 % duty cycle. Because the coil is 12 Ω, a 3.3 V MCU pin that can deliver 100 mA may drive the buzzer directly. If the pin current is lower, an NPN transistor with a base resistor provides a robust alternative. A small flyback diode across the coil is recommended to protect the driver.
4. Does the centre‑hole design affect the frequency or SPL compared with an offset‑hole buzzer?
The resonant frequency and rated SPL are identical. The advantage of the centre hole is a more uniform sound field: the sound pressure level varies less as the measurement angle changes. This is particularly useful when the device orientation is not fixed.
5. Can the MLT‑5020H be driven at frequencies other than 4 kHz?
It will respond to drive signals over a range of frequencies, but the maximum output occurs at the mechanical resonance of 4000 ± 300 Hz. Driving outside this band will reduce the sound level. For applications that need a variable tone, it is best to stay close to the resonant point.
To request a quotation, order engineering samples or discuss custom modifications, contact MEIDI through the enquiry form. The applications team can provide layout recommendations, drive circuit schematics and acoustic simulation data for your enclosure design.
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