TDK Announces First MIPI Standard SoundWire MEMS Microphone

January 21 2020, 01:15
Among the many interesting demonstrations of new audio solutions for developers presented by TDK at CES 2020, the T5808 MIPI standard SoundWire microphone stands out as a "world's first," using the MIPI Alliance SoundWire compliant digital interface which allows bi-directional data flow. The T5808 is a multi-mode, low noise digital MEMS microphone in a small package, consisting of a MEMS microphone element and an impedance converter amplifier followed by a fourth-order Σ-Δ modulator. 

A 66 dB SNR/135dB Acoustic Overload Point (AOP) digital microphone, the TDK T5808 supports solutions based on the SoundWire 1.1 open standard defined by the Mobile Industry Processor Interface (MIPI) Alliance for mobile, IoT and other consumer devices, and supporting up to seven individually configurable microphones on a single audio bus.

This new TDK microphone pushes the boundaries of digital microphone acoustic performance while providing advanced feature sets with very low power. Main target applications include obviously smartphones, but also all types of microphone arrays for tablets, cameras, notebook PCs, and obviously Bluetooth headsets.

The T5808 SoundWire microphone has multiple modes of operation - High Quality, Low Power Listen (Always-On), Concurrent and Idle (sleep) - maintaining its high SNR and high AOP in all operational modes. The T5808 features 66 dBA SNR and 135dB SPL AOP at 650 µA in high quality mode (HQM), and decreases power consumption to 215µA in low power mode (LPM). The T5808 microphone also features concurrent mode (CCM), enabling simultaneous audio streams from HQM and LPM that can seamlessly transition back and forth without audio glitches.

Available in a standard 3.5 × 2.65 × 0.98 mm surface-mount package, the T5808 is reflow solder compatible with no sensitivity degradation. The microphone is currently in mass production and available for sampling and distribution in Q1 2020.
The  T5808 SoundWire demonstration platform, using a seven-microphone array, at CES 2020.
SoundWire is a standard audio bus that supports multiple audio devices including microphones, speakers, codecs and class D amplifiers, redefining how audio devices and ICs communicate by integrating audio and control data for up to 11 devices (e.g. 7 mics, 4 speakers) on a single bus. Introduced in 2014 and updated in 2019 (v1.2), the open standard consolidates many of the key attributes in mobile and PC audio interfaces, providing a common, comprehensive interface and scalable architecture that can be used to enable audio features and functions in multiple types of devices. It supports the use of advanced amplifiers and microphones, and can also optimize speaker protection, microphone power and performance, noise cancellation and always-listening audio input.

The SoundWire Standards Committee, who created the MIPI standard for SoundWire, includes technology leaders in application processors, audio DSPs and codecs, and other ICs. The MIPI SoundWire is developed by the MIPI Audio Working Group.

“As a member of the SoundWire Standards Committee, Qualcomm Technologies has supported the SoundWire interface on speaker amplifier products for a number of years. We are excited to see TDK’s microphone technology now incorporating this interface,” says Rahul Shinkre, Director, Product Management at Qualcomm Technologies, Inc.

New T5818 Microphone
TDK demonstrated the new T5808 SoundWire microphone along with its comprehensive portfolio of passive components, sensors, power supplies and batteries at CES 2020, in Las Vegas, Nevada. New at the show was the T5818, a Pulse Density Modulation (PDM) microphone with a dynamic range of 107dB at 590µA, the widest dynamic range in the industry at the lowest power, which allows for excellent acoustic performance in environments that shift from very quiet to very loud, such as far field voice pickup barge-in for Smart Speaker applications.

This new microphone features 66dBA SNR, 135dB SPL AOP, at 590 µA in High Quality Mode (HQM), and decreases power consumption to 215 µA in Low Power Mode (LPM). It is essential for capturing high quality audio inputs, which plays a vital role for AI engines and cloud-based applications that require a PDM microphone interface. Current analog output wide dynamic range microphones require expensive ADCs to take advantage of full acoustic capabilities. The T5818 provides this ADC conversion while maintaining excellent dynamic range with the benefits of a PDM low latency bit stream, making it suitable for a wide range of applications, from mobile phones to ANC headphones.
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