Comparison of Digital PDM and I²S Interfaces in MEMS Microphones
Micro-electro-mechanical systems (MEMS) microphones are increasingly used in modern mobile devices and many other audio systems. These microphones make use of digital interfaces such as Pulse-density Modulation (PDM) and Inter-IC Sound (I²S) to communicate audio data. These two interfaces offer their own advantages and disadvantages, and are used in various applications.
PDM is a digital interface that is used to transmit audio data over short distances. It is used to convert an analog signal into a serial digital data stream, and is usually implemented with a one-bit signal. This makes it simple to implement, since there are only two signal levels (high and low). This also leads to a reduced signal-to-noise ratio (SNR), making it best suited for applications that don’t require high-fidelity audio. This type of interface is often used in devices that are battery-powered, since it requires less power than other digital interfaces.
In contrast, I²S is a universal digital interface used to transmit audio between digital devices and DACs. This interface uses a byte-serial protocol to transmit digital audio data and typically supports multiple channels of audio. Like PDM, I²S also has a reduced SNR and is best suited for applications that do not require high fidelity audio. The main advantage of I²S is that it is a universal interface and can be used to connect various types of digital devices and DACs.
MEMS microphones typically use PDM or I²S interfaces to communicate the audio signals they are sensing. The choice of which interface to use usually depends on the application. PDM is best suited for applications that do not require high quality audio and can benefit from lower power consumption. I²S is a more versatile interface and is best suited for applications that require the ability to connect to various types of digital devices and DACs.
Both PDM and I²S are popular interfaces for MEMS microphones, each offering different advantages. PDM is better suited for applications that require low power consumption, while I²S is better suited for applications that require more versatility. Both interfaces offer their own advantages and disadvantages, and are used in various applications. It is important to understand these interfaces and their differences in order to choose the right one for a given application.
In conclusion, PDM and I²S are both popular interfaces for MEMS microphones, each offering different advantages. PDM is simpler to implement and requires less power, while I²S is more versatile and can be used to connect to various types of digital devices and DACs. When deciding which of these interfaces to use, it is important to consider the application and its requirements in order to make the best choice.