8.5*8.5*3mm SMD Magnetic Passive Buzzer

Series at a Glance

Two coil resistances from one mechanical design: 16 Ω for lower‑voltage applications and 32 Ω for standard 5 V rails.

External drive required. The passive electromagnetic structure expects an AC waveform, typically a 2700 Hz square wave, which provides the freedom to implement custom tone patterns, variable durations and multi‑tone alerts entirely through software.

Guaranteed sound output of at least 85 dB at a 10 cm distance, measured at the rated voltage for each variant.

Resonant frequency 2700 ± 300 Hz, with batch sample data confirming a tight 2700 Hz centre across multiple units.

Compact 8.5 × 8.5 mm footprint and 3.0 mm height, designed for dense SMT assemblies where board area and clearance are both constrained.

Operating temperature range from −30 °C to +70 °C, supporting cold‑start conditions and outdoor enclosures.

Black LCP housing compatible with reflow soldering up to 255 ± 5 °C, as well as wave and manual processes.

Key Characteristics

A single PCB land pattern accommodates both the 16 Ω and 32 Ω parts, enabling platform designs that can be populated according to the target system voltage without layout changes.

The passive drive architecture relies on an externally generated square wave, which allows the microcontroller to define tone frequency, repetition rate and pattern. There is no internal oscillator to constrain the acoustic behaviour.

Acoustic output is specified at a minimum of 85 dB for both variants, with a resonant frequency of 2700 Hz and a tolerance of ±300 Hz.

Current consumption is rated at ≤100 mA for the 16 Ω version at 3.6 V and ≤80 mA for the 32 Ω version at 5 V, providing clear figures for power supply sizing.

The 3.0 mm height keeps the component within the z‑envelope of many multi‑board systems, while the 8.5 mm square footprint preserves adjacent routing channels.

Continuous operation is specified from −30 °C, a lower limit that extends the usable range beyond what many commercial‑grade buzzers offer.

The black LCP package withstands reflow, wave and hand soldering profiles, giving manufacturers flexibility in assembly sequence.

Application Scenarios

The application notes below are based on the electrical and environmental specifications of the 8.5*8.5*3mm SMD Magnetic Passive Buzzer. They are not design guarantees; verify performance against your specific requirements and applicable standards.

Industrial automation panels: fault alarms and process status indicators in PLC and motor drive systems benefit from the dual‑impedance option, which aligns with both 3.3 V and 5 V control logic without board changes.

Security and access control: intrusion panels and card readers can generate distinctive PWM‑controlled alert rhythms, helping operators distinguish between different events.

Building and home automation: gateway hubs, smoke detector interconnects and thermostat confirmations rely on the buzzer’s ability to produce software‑defined notification patterns.

Battery‑powered instruments: the 16 Ω variant suits 3.3 V Li‑ion systems, while the 32 Ω variant is optimised for 5 V regulated supplies, covering a wide range of portable equipment.

Telecommunications infrastructure: cabinet intrusion and power‑failure alarms in outdoor or unheated locations benefit from the −30 °C lower operating limit.

Outdoor and thermally exposed enclosures: equipment subjected to wide temperature swings can depend on the specified −30 °C to +70 °C operating range for consistent alert generation.

Frequently Asked Questions

1. How do I decide between the MLT‑8530H‑16R and the MLT‑8530H‑32R?

The choice depends on your available drive voltage and how much current your power supply can deliver. The 16 Ω part operates from 2.5 V to 4.5 V and is a natural fit for 3.3 V logic or single‑cell Li‑ion designs. The 32 Ω part works from 4.5 V to 6.5 V, matching standard 5 V rails and drawing less current for the same acoustic output. Because both share the same land pattern, you can evaluate one variant and later switch to the other without modifying the PCB.

2. What drive circuit should I use for each variant?

Both types require an external square wave at 2700 Hz and the rated voltage. A transistor buffer or logic‑level MOSFET is needed because the coil current (≤100 mA for the 16 Ω, ≤80 mA for the 32 Ω) exceeds the capability of most microcontroller GPIO pins. A simple NPN transistor with a base resistor is the most common solution. Dedicated buzzer driver ICs can also be used; ensure the output frequency is set to 2700 Hz to hit the resonance point.

3. Can I run the MLT‑8530H‑16R on a 5 V supply, or the 32 Ω version on 3.3 V?

Operating the 16 Ω variant above 4.5 V risks overheating the coil. The 32 Ω variant below 4.5 V will produce reduced sound output that may fall below the specified 85 dB minimum. If your system voltage is fixed and does not match the natural range of either part, MEIDI can suggest alternative models or discuss a small‑value series resistor for the 16 Ω version, though this will lower the sound pressure.

4. What is the significance of the 2700 Hz frequency compared to 4000 Hz buzzers?

The 2700 Hz centre frequency is lower than the 4 kHz typical of many compact SMD buzzers. Both sit within the band where human hearing is sensitive, but the lower pitch may be perceived as less shrill and can behave differently inside an enclosure. The best choice depends on the ambient noise spectrum and the type of alert differentiation your product needs. Prototype testing with both frequency ranges is recommended if the tonal quality is critical.

5. What do the sample measurement tables tell me?

The 10‑unit sample data shows the typical performance spread for sound pressure, current, frequency and impedance. These figures are informative only and do not replace the guaranteed limits: ≥85 dB, 2700 ± 300 Hz, and coil resistance within ±3 Ω of the nominal value. Production batch reports that document these parameters for every shipment are available upon request.