System Plus examines iPhone 7’s MEMS mics

Article By : Vivek Nanda

In a breakdown of the iPhone 7 Plus, System Plus Consulting finds 4 MEMS microphones and reveals they present totally different internal structures.

Yole Développement has forecast a 10% CAGR between 2015 and 2021 in the MEMS microphones market. Yole analysts said that the growth is due to high demand from the smartphone and home appliances market segment. MEMS in smartphones have near-100% penetration in the segment.

System Plus Consulting, a costing company, shared a technical analysis of the 4 microphones embedded in the Apple iPhone 7 Plus. Apple can be recalled earlier ordering MEMS microphones for the iPhone 7 from Goertek/Infineon Technologies, Knowles and STMicroelectronics. Is there an added value of each device?

The Apple iPhone 7 and 7 Plus each features the following MEMS microphones:
• A front-facing top microphone,
• Two front-facing bottom microphones,
• And a rear-facing top microphone.

 

Figure 1: System Plus Consulting's teardown of iPhone 7 Plus showing sources of MEMS microphones. (Source: Apple iPhone 7 Plus: MEMS Microphones, a report by System Plus.)
 

System Plus said the two front-facing bottom microphones were sourced by either Knowles or Goertek. The firm added that the MEMS landscape now has a lot of companies, including Knowles, AAC Technologies, Infineon Technologies, Goertek, STMicroelectronics, Gettop, InvenSense, Bosch Akustica and Cirrus Logic. The company said Knowles, AAC and Goertek are considered top players in the consumer market, while Knowles also addresses the medical application of hearing aids.

Manufacturing capabilities

On the manufacturing process, System Plus Consulting emphasised the in-house manufacturing capability at STMicroelectronics. STMicroelectronics makes MEMS die internally without relying on the Japanese company, Omron, according to Sylvain Hallerau, analyst at System Plus.

Goertek, however, relies on Infineon Technologies for die manufacturing. The company integrates the latest Infineon Technologies MEMS microphone, which delivers a differential MEMS microphone using a dual backplate technology. Knowles, meanwhile, makes strategic technical choices internally to reduce die size.

The 4 microphone technologies share the same Apple-specific package dimensions. However, they present totally different internal structures, including the number of substrate metal layers and the embedded capacitance.