{"id":15157,"date":"2025-05-22T12:17:48","date_gmt":"2025-05-22T12:17:48","guid":{"rendered":"https:\/\/sistc.com\/?p=15157"},"modified":"2025-05-22T12:17:49","modified_gmt":"2025-05-22T12:17:49","slug":"what-is-the-digital-output-of-a-mems-microphone","status":"publish","type":"post","link":"https:\/\/sistc.com\/zh\/what-is-the-digital-output-of-a-mems-microphone\/","title":{"rendered":"\u4ec0\u4e48\u662f MEMS \u9ea6\u514b\u98ce\u7684\u6570\u5b57\u8f93\u51fa\uff1f"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">In modern audio system design, MEMS (Micro-Electro-Mechanical Systems) microphones have largely replaced traditional analog microphones\u2014thanks to their tiny size, low power consumption, and robust performance. One of their greatest advantages is the <strong>digital output<\/strong>, which simplifies integration and improves noise immunity. In this article, we\u2019ll explore the two most common digital interfaces for MEMS microphones, compare their characteristics, and show how to choose the right format for your application.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-1024x1024.jpg\" alt=\"\" class=\"wp-image-15158\" style=\"width:231px;height:auto\" srcset=\"https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-1024x1024.jpg 1024w, https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-300x300.jpg 300w, https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-100x100.jpg 100w, https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-768x768.jpg 768w, https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-1536x1536.jpg 1536w, https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-2048x2048.jpg 2048w, https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-12x12.jpg 12w, https:\/\/sistc.com\/wp-content\/uploads\/2025\/05\/IMG_9229-600x600.jpg 600w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\"><a href=\"https:\/\/sistc.com\/product\/digital-mems-microphone\/\">Digital MEMS Microphone<\/a><\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">1. Why Digital Output Matters<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Unlike analog microphones, which output a variable voltage that must be routed through anti-aliasing filters and an external ADC (Analog-to-Digital Converter), digital MEMS microphones integrate the ADC on-chip. This yields:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Superior EMI Immunity<\/strong><br>The signal is digitized right at the diaphragm, so it isn\u2019t corrupted by electromagnetic noise along the PCB traces.<\/li>\n\n\n\n<li><strong>Simplified PCB Layout<\/strong><br>No need for precision analog routing or additional filtering components.<\/li>\n\n\n\n<li><strong>Consistent Performance<\/strong><br>Tight factory calibration of the ADC ensures minimal part-to-part variation.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">2. The Two Main Digital Interfaces<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">2.1 PDM (Pulse Density Modulation)<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>How It Works:<\/strong> Outputs a one-bit high-rate stream whose density corresponds to the sound pressure level.<\/li>\n\n\n\n<li><strong>Clocking:<\/strong> Requires a single clock line (typically 1\u20133 MHz).<\/li>\n\n\n\n<li><strong>Pros:<\/strong>\n<ul class=\"wp-block-list\">\n<li>Very simple interface<\/li>\n\n\n\n<li>Low pin count<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Cons:<\/strong>\n<ul class=\"wp-block-list\">\n<li>Requires significant MCU\/DSP processing to decimate and filter<\/li>\n\n\n\n<li>May need careful PCB layout for high-speed clock<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">2.2 I\u00b2S (Integrated Inter-IC Sound)<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>How It Works:<\/strong> Sends multi-bit digital audio words (usually 16\u201324 bits) synchronized by a word select and bit clock.<\/li>\n\n\n\n<li><strong>Clocking:<\/strong> Two or three lines: Bit Clock (BCLK), Word Select (WS), and optionally Master Clock (MCLK).<\/li>\n\n\n\n<li><strong>Pros:<\/strong>\n<ul class=\"wp-block-list\">\n<li>High audio resolution without extra filtering<\/li>\n\n\n\n<li>Native support in many audio codecs and DSPs<\/li>\n\n\n\n<li>Facilitates multi-mic synchronization<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Cons:<\/strong>\n<ul class=\"wp-block-list\">\n<li>More pins required<\/li>\n\n\n\n<li>Slightly higher BOM and routing complexity<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">3. Choosing Between PDM and I\u00b2S<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Criterion<\/th><th>PDM<\/th><th>I\u00b2S<\/th><\/tr><\/thead><tbody><tr><td><strong>Pin Count<\/strong><\/td><td>Low (Data + Clock)<\/td><td>Higher (BCLK + WS [+ MCLK])<\/td><\/tr><tr><td><strong>Processing Load<\/strong><\/td><td>High (decimation\/filter in firmware)<\/td><td>Low (direct multi-bit data)<\/td><\/tr><tr><td><strong>Audio Quality<\/strong><\/td><td>Depends on decimation filter design<\/td><td>Native high-bit resolution<\/td><\/tr><tr><td><strong>Multi-Mic Arrays<\/strong><\/td><td>Possible, but complex<\/td><td>Easier sync via shared clocks<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Use PDM<\/strong> when you need the simplest hardware interface and have plenty of processing headroom to filter the data stream in software.<br><strong>Use I\u00b2S<\/strong> when you need higher resolution audio, easier synchronization between multiple microphones, or compatibility with standard audio peripherals.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">4. SISTC\u2019s MEMS Microphones with Digital Output<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">At <strong>Wuxi Silicon Source Technology Co., Ltd.<\/strong>, our digital MEMS microphones support both PDM and I\u00b2S interfaces, offering designers maximum flexibility:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><a class=\"\" href=\"https:\/\/sistc.com\/product\/digital-mems-microphone\/\">DM2611 Digital MEMS Microphone<\/a><\/strong><br>\u2022 SNR: 64 dB | AOP: 125 dB SPL | Interfaces: PDM &amp; I\u00b2S<\/li>\n\n\n\n<li><strong><a class=\"\" href=\"https:\/\/sistc.com\/product\/digital-mems-microphone\/\">DM4710 Ultra-Low Power MEMS Microphone<\/a><\/strong><br>\u2022 Operating Current: 12 \u00b5A | SNR: 62 dB | Interfaces: PDM &amp; I\u00b2S<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Whether you\u2019re building smart speakers, wearables, or automotive voice-control systems, these parts deliver reliable digital audio that\u2019s easy to integrate.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">5. Further Reading<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>PDM vs. I\u00b2S: Choosing the Right Digital Microphone Interface<\/strong> \u2013 Analog Devices technical brief\u00b9<\/li>\n\n\n\n<li><strong>MEMS Microphone Fundamentals<\/strong> \u2013 TDK InvenSense whitepaper\u00b2<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u00b9 <a>https:\/\/www.analog.com\/en\/technical-articles\/understanding-pdm-and-i2s-interfaces.html<\/a><br>\u00b2 <a>https:\/\/www.invensense.tdk.com\/technology\/mems-microphones\/<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In modern audio system design, MEMS (Micro-Electro-Mechanical Systems) microphones have largely replaced traditional analog microphones\u2014thanks to their tiny size, low power consumption, and robust performance. One of their greatest advantages [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":15158,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_joinchat":[],"footnotes":""},"categories":[1],"tags":[],"class_list":["post-15157","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-company-news"],"_links":{"self":[{"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/posts\/15157","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/comments?post=15157"}],"version-history":[{"count":0,"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/posts\/15157\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/media\/15158"}],"wp:attachment":[{"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/media?parent=15157"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/categories?post=15157"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sistc.com\/zh\/wp-json\/wp\/v2\/tags?post=15157"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}