MEMS Microphone
MEMS microphones are microphones produced using microelectromechanical system processing technology. MEMS microphones are also commonly referred to as microphone chips, silicon microphones, which are effectively etched into semiconductor silicon wafers. The pressure-sensitive removable membrane (septum) is etched behind the fixed perforated plate. The perforated retaining plate and diaphragm work together to form a capacitor (much like the design of a condenser microphone). Like most MEMS technologies, MEMS microphones are manufactured on the production line using semiconductor silicon wafers and highly automated processes. Different layers of different materials are stacked on top of the silicon wafer and then etched away the unwanted material. Once etched is complete, the transducer element of the MEMS microphone has a movable diaphragm, a fixed but perforated plate, and a surrounding enclosure. ASICs (application-specific integrated circuits) are designed to work with the transducer elements of MEMS microphones. It uses a charge pump to place a fixed charge between the fixing plate and the microphone film. ASICs are specialized microchips.
Advantages of MEMS Microphone
Size matters
MEMS microphones are incredibly compact, making them
suitable for applications where space is limited.
They are commonly used in smartphones, tablets, and
wearable devices, where miniaturization is critical.
Power efficiency
These microphones consume minimal power, which is
crucial for portable devices with limited battery
capacity. This ensures extended battery life for
your gadgets.
High-quality sound
Despite their small size, MEMS microphones offer
impressive audio quality, with excellent sensitivity
and signal-to-noise ratios. This makes them ideal
for capturing crisp and clear sound.
Durability
MEMS microphones are rugged and less prone to damage
from mechanical shock or vibration, making them
suitable for harsh environments and industrial
applications.
High reliability
MEMS reliability outperforms that of a similar
system assembled from discrete components. Because
of their small size and weight, MEMS mechanical
assemblies perform better in vibration and impact
conditions.
Low cost
The low cost of MEMS-based devices and MEMS scanning
mirror can be attributed to their high
processability and the ability to design using
commercially available functionally finished
components.The range of MEMS applications is
constantly expanding. Some of them are already
visible, most notably on smart roads, where MEMS are
embedded in the pavement to monitor its condition.
Why Choose Us
Quality assurance
In terms of quality assurance, the company strictly follows the standards and norms of the industry quality system. Adopt industry-leading testing equipment to ensure product quality and good reputation.
Professional service
We can accept factory inspection and goods inspection at any time. Technical discussion, research and development of new products, and complete after-sales service.
Cheap price
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Oem/odm
When you put forward your needs, our engineers will provide you with faster and more perfect customized solutions. We have a wide range of products, and we will provide technical support according to your actual needs to choose the right product for you.
MEMS Microphone Output Interface Category
Analog Single-ended
This is a commonly used format, and the price is usually lower
than the Differential type. The sensitivity is generally in
the range of -38dBV ~ 40dBV. All the audio codec microphone
inputs support this signal and make it the most popular one.
But when designing the PCB circuit for this kind of
microphone.
Analog differential-ended
This type is uncommon, and the price is usually higher than
Single-ended. It is a Differential Output. Therefore, the
sensitivity will also increase by 6dBV. The sensitivity is
generally set around -32dBV, and it can also increase the AOP
(Acoustic Overload Point). Most audio codec microphone inputs
also support this signal.
PDM (Pulse Density Modulation)
It is the main output interface of a digital MEMS microphone.
The L/R channel shares the Data BUS, so it only needs four
lines to complete the stereo L/R channel transmission; it is
also suitable for the PCB layout design of portable devices.
I2S (Integrated Internship Sound)
This digital audio serial bus standard format was developed by
Philips to transmit audio data between digital audio devices.
The bus is used explicitly for data transmission between audio
devices, widely used in various multimedia systems. Most
entry-level MCUs don't support PDM interfaces but basic
I2S interfaces. Therefore, some microphone manufacturers have
still launched I2S MEMES microphones for applications without
an audio codec.
TDM (Time-division multiplexing)
It divides the usage time of the transmission medium several
fixed time slots. Each time slot occupies a short period (for
example, 20ms) and is considered a virtual channel. When data
are communicated, the two interconnected parties will be set
to transmit data in a particular time slot. It has the right
to use the transmission intermediary for a specific time. For
a longer time, the entire transmission intermediary is the
same as having multiple connections, and they send data
simultaneously.
Application of MEMS Microphone
Smart home devices
MEMS microphones are integrated into smart speakers, virtual
assistants, and home automation systems. They enable voice
commands, allowing users to control lights, thermostats, and other
smart devices with spoken instructions.
Security systems
MEMS microphones are used in security cameras and surveillance
systems. They capture audio to enhance video footage, providing
valuable context for security personnel. Advanced models can
detect specific sounds, such as breaking glass or alarms,
triggering appropriate responses.
Medical devices
In medical applications, MEMS microphones are utilized in devices
like hearing aids and assistive listening devices. They improve
sound clarity, enhancing the hearing experience for individuals
with hearing impairments.
Industrial automation
MEMS microphones are used in industrial settings to monitor
equipment and detect abnormalities. They can detect unusual sounds
or vibrations in machines, indicating potential issues that
require maintenance or repair.
Consumer electronics
MEMS microphones are integral components of consumer electronics,
such as digital cameras and camcorders. They capture high-quality
audio during video recording, ensuring the recorded content is
immersive and engaging.
Gaming accessorie
MEMS microphones are used in gaming peripherals like headsets and
microphones. They capture clear voice communications during online
gaming, enabling players to strategize and coordinate effectively.
Educational tools
MEMS microphones are incorporated into educational devices and
language-learning tools. They facilitate interactive learning
experiences, allowing students to engage in language practice and
pronunciation exercises.
Iot devices
MEMS microphones are used in various connected devices in the
internet of things (iot) ecosystem. For example, they can be
integrated into smart appliances to receive voice commands, making
these appliances part of the smart home network.
Navigation systems
MEMS microphones are utilized in navigation devices for capturing
spoken instructions. They enhance the user experience by providing
voice-guided directions, mainly when visual guidance is limited or
unsafe, such as while driving.
Comparing MEMS Microphones and Electret Condenser Microphones
MEMS Microphones
Pioneering Miniaturization and Precision
MEMS microphones excel with compactness, integrated PCBs and
ADCs, low impedance for noise rejection, resilience to
vibrations, and continuous advancements, making them ideal
for space-constrained applications demanding high-quality
audio capture.
Electret Condenser Microphones
Versatility and Legacy Appeal
ECMs remain valuable for legacy integration, diverse
connectivity options, environmental resilience, directional
flexibility, and voltage tolerance. They are preferred for
seamless upgrades and backward compatibility and excel in
various scenarios with established designs.
The choice between MEMS microphones and ECMs depends on the application's precise demands, legacy systems, and environmental considerations. MEMS microphones offer compactness and high performance, while ECMs provide versatility and compatibility with established designs.
Components of MEMS Microphone
Diaphragm
Located on top of the microphone, is a very thin film, usually made of metal or ceramic material. The diaphragm vibrates with the fluctuations of the sound.
Backplate
Located underneath the diaphragm, it is usually made of solid material. There is an electrode on the backplate that senses the vibration of the diaphragm.
Air Gap
A tiny gap between the diaphragm and the backplate, in which the diaphragm will vibrate when the sound fluctuates.
Support structure
A stable frame structure used to support the diaphragm and backplate.
Inductor
An electronic device located on a support structure that measures the vibration of the diaphragm and converts it into an electrical signal.
How to Choose a MEMS Microphone
Power consumption
Power consumption is one of the most critical design
considerations, especially for portable and handheld electronic
devices. Therefore, the selection of power-efficient MEMS
microphones is crucial. Compared to conventional microphones, MEMS
microphones consume less power because all the circuitry is housed
in a single IC package. Moreover, analogue MEMS sensors consume
less energy than digital ones because of fewer stages.
Dimensions
The microphone size is another important consideration in the
design of modern portable electronic devices. Electronic gadgets
are shrinking daily, and available space is quite limited. MEMS
microphones are excellent in this regard because of their small
form factor. Due to this reason, manufacturers use these
microphones in tablets, mobile phones, smartwatches, and other
portable devices.
Noise floor
Noise, EMI, and buzzing are the biggest challenges in
high-frequency electronic circuits. Distortion in output signal
can lead to erroneous results and poor quality. The amount of
noise in the output signal in a quiet environment is known as the
microphone’s noise floor. Noise levels directly impact the
SNR of the microphone. Analogue microphones are more susceptible
to noise than digital microphones. MEMS microphones feature
on-chip signal conditioning circuitry to minimize noise and
interference.
Distortion
Total Harmonic Distortion (THD) is the deviation of a signal from
its actual waveform. Signal distortion in an audio system can
cause poor sound quality and user experience. The most common
cause of signal distortion is various types of noise and
interference.
Frequency response
Frequency response is the variation in microphone sensitivity at
different frequencies. The typical frequency range within which
MEMS sensors operate satisfactorily lies between 100Hz and 10 kHz.
As a result, high-performance MEMS microphones provide a flat
frequency response over the entire audible range, i.e. 20 Hz to 20
kHz.
Power supply rejection
PSP is another critical factor in the selection of MEMS
microphones. The ability of the microphone to reject the power
supply noise is known as PSR. In poor-quality microphones, the
power supply noise often appears at the output signal, which
causes distortion and sound quality issues.
Directionality
Board-level microphones can either be omni or uni-directional.
Uni-directional microphones can only gather sound from a
particular direction, while omnidirectional microphones can
receive sound from any direction. Therefore, the directionality of
a microphone is a crucial factor in its selection for a specific
application.
MEMS microphone contains both electronic and mechanical components on the same semiconductor wafer. It has a transducer and an application-specific integrated circuit (ASIC) integrated into a single component protected by a mechanical cover. A small hole on the cover or the base PCB allows the sound into the microphone. It is either top-ported or bottom-ported, depending on whether the hole is in the top cover or the PCB.
The image below shows that it consists of a micro-sized pressure-sensitive diaphragm transducer and signals conditioning pre-amplifier circuitry. In addition, the Digital version of the MEMS sensor has a digital converter to convert the analogue signal to a digital signal.
The micro-sized pressure-sensitive diaphragm acts as a
single plate of a capacitor. The ASIC-based charge pump
circuit injects charge between the capacitor plates.
The diaphragm movement due to sound pressure changes the
capacitance, which in turn causes the generation of an
electrical signal. This electrical audio signal is then fed
to the pre-amplifier.
An impedance converter reduces the output impedance of the
signal to something usable before feeding into the
amplifier.
What Are the Trends and Development Directions of MEMS Microphone in the Market
Higher SNR
MEMS microphone performance continues to improve. SNRs have
increased from 55 – 58 dB a few years ago to 63 – 66
dB today, resulting in cleaner audio capture and allowing
microphones to be used at greater distances with the same level of
clarity. High SNR levels are needed by automatic speech
recognition algorithms to achieve good word accuracy rates.
Higher sound pressure levels
Many microphone users are also requesting higher acoustic overload
points to prevent distortion in loud environments. Distortion
caused by clipping at sound pressure levels above the acoustic
overload point can make recordings made in loud environments such
as rock concerts unusable.
Smaller package sizes
MEMS microphone package sizes are also shrinking as consumer
demand for thinner, lighter products continues to increase. Early
MEMS microphones had package sizes of 3.76mm x 4.72mm x 1.25mm
while today 3mm x 4mm x 1mm and 2.95mm x 3.76mm x 1mm packages are
common. Newer MEMS microphones are available in 2.5mm x 3.35mm x
0.98mm and 2.65mm x 3.5mm x 0.98mm packages. This trend is likely
to continue, although smaller microphone packages make it more
difficult to maintain or improve audio quality due to the
shrinking size of the microphone’s back chamber.
Ambient noise reduction
Many smartphones and tablets are starting to use more than one
microphone to enable features such as video recording. Another
common way in which multiple microphones are used is for ambient
noise reduction. Many smartphones use a microphone located on the
top or the back of the phone to detect noise in the surrounding
environment and subtract it from the output from the voice
microphone(s) to help improve intelligibility. Microphones whose
primary purpose is video recording are frequently also used for
ambient noise reduction.
Tighter control of sensitivity
The performance algorithms used to perform functions such as noise
cancellation and beamforming usually assume that the sensitivity
of the microphones being used is the same, so variations in
sensitivity between the microphones in an array hurt the
performance of the algorithms.
Company Profile
Shenzhen Marquess Electronics Co., Ltd. was founded in July 2004, originating from the Japanese AOI Electric Motor Manufacturing Company as a joint venture specializing in the production of ECM (Electret Condenser Microphones).
Our Certificate
ISO 9001 2015,ISO 14001 2015,ISO 4500 12018,UL E473299,UL E473487
FAQ
Q: What is a MEMS Microphone?
Q: How does a MEMS Microphone differ from traditional microphones?
Q: What are the advantages of using a MEMS Microphone?
Q: In what devices are MEMS Microphones commonly found?
Q: Do MEMS Microphones require phantom power to operate?
Q: Are MEMS Microphones more durable than traditional microphones?
Q: Can MEMS Microphones capture high-quality audio recordings?
Q: What is the frequency response range of MEMS Microphones?
Q: Are MEMS Microphones suitable for voice recognition and voice control applications?
Q: Do MEMS Microphones offer noise-canceling features?
Q: Can MEMS Microphones be used for recording music and instruments?
Q: Do MEMS Microphones require special handling or maintenance?
Q: Are MEMS Microphones sensitive to environmental factors like humidity and temperature?
Q: What is the typical signal-to-noise ratio (SNR) of MEMS Microphones?
Q: Can MEMS Microphones be integrated into wearable devices?
Q: Do MEMS Microphones offer multiple polar patterns like traditional microphones?
Q: What is the power consumption of MEMS Microphones compared to traditional microphones?
Q: Are MEMS Microphones cost-effective compared to traditional microphones?
Q: Can MEMS Microphones be used for teleconferencing and video calls?
Q: What advancements can we expect in MEMS Microphone technology in the future?