iPhone 4 Microphone Teardown
The phone's microphone, a component likely experiencing more verbal interaction than any other device or person globally, warrants detailed examination.
Microphones are essential components often overlooked in daily use, performing numerous functions without receiving recognition, despite their technical sophistication and design.
- Chipworks collaborated with us to demonstrate the several microphones found within an iPhone 4.
These microphones, typical of those found in modern smartphones, exemplify common designs and performance characteristics without incorporating any unique or exceptional technology.
Step 1 | iPhone 4 Microphone Teardown
The iPhone incorporates a total of three microphones—two positioned within the device's body and one integrated into the provided Apple earbuds. Based on their placement, one microphone is likely dedicated to voice calls, while the other serves to record video and reduce background noise.
The Knowles S1950 and Infineon 1014 microphones, as shown in the accompanying image, are components of the iPhone 4's handset, whereas the earbuds incorporate a Knowles S199 microphone.
The Knowles S1950 and Infineon 1014 microphones, as shown in the accompanying image, are components of the iPhone 4's handset, whereas the earbuds incorporate a Knowles S199 microphone.
Step 2
The iPhone's speaker-facing microphone, identified as a Knowles S1950 component, represents one of two microphones present within the device.
Knowles' MEMS microphones utilize a proprietary CMOS/MEMS fabrication process, enabling remarkably compact designs, reduced height, and diverse mounting possibilities.
Due to its diminutive size, measuring only 3mm by 4mm, this microphone utilizes surface-mount technology, requiring automated placement onto the logic board.
Employing surface-mount technology proves advantageous during production, as it enables simultaneous component placement onto the printed circuit board, thereby removing the expense of pre-assembled sub-units and reducing the bill of materials cost. Furthermore, this design approach facilitates component mounting on both the upper and lower surfaces of the board, a capability unavailable with traditional thru-hole methods.
Knowles' MEMS microphones utilize a proprietary CMOS/MEMS fabrication process, enabling remarkably compact designs, reduced height, and diverse mounting possibilities.
Due to its diminutive size, measuring only 3mm by 4mm, this microphone utilizes surface-mount technology, requiring automated placement onto the logic board.
Employing surface-mount technology proves advantageous during production, as it enables simultaneous component placement onto the printed circuit board, thereby removing the expense of pre-assembled sub-units and reducing the bill of materials cost. Furthermore, this design approach facilitates component mounting on both the upper and lower surfaces of the board, a capability unavailable with traditional thru-hole methods.
Step 3
The Knowles S1950 microphone, consistent with other iPhone 4 microphones, functions through the integrated collaboration of two distinct components: a MEMS and an ASIC; the MEMS handles the mechanical transduction of sound, while the ASIC processes the resulting electrical signals.
The S1950 MEMS die's construction reveals its operational principles; its microphone resembles a miniature condenser microphone, utilizing a capacitor formed by two parallel plates crafted from polysilicon—extremely thin structures composed of numerous small silicon crystals.
Sound waves impacting the upper plate, which features numerous small holes and is positioned with a slight space from the lower plate, induce a minimal displacement. This movement, occurring in a capacitor where both plates carry an electrical charge, results in subtle fluctuations within the electric field. The stationary lower capacitor plate detects and transmits these variations as an analog signal.
The S1950 MEMS die's construction reveals its operational principles; its microphone resembles a miniature condenser microphone, utilizing a capacitor formed by two parallel plates crafted from polysilicon—extremely thin structures composed of numerous small silicon crystals.
Sound waves impacting the upper plate, which features numerous small holes and is positioned with a slight space from the lower plate, induce a minimal displacement. This movement, occurring in a capacitor where both plates carry an electrical charge, results in subtle fluctuations within the electric field. The stationary lower capacitor plate detects and transmits these variations as an analog signal.
Step 4
The iPhone 4 microphone's S1950 ASIC die receives and translates the analog output from the MEMS die, performing signal processing and relaying the resulting data to the device's processor.
The integrated analog-to-digital converter within the microphone simplifies connection to other digital circuits.
The integrated analog-to-digital converter within the microphone simplifies connection to other digital circuits.
Step 5
The handset incorporates the 1014 microphone, produced by Infineon, a company that has recently entered the MEMS market, previously largely populated by smaller, newer businesses.
Due to increased production volume and broader availability, microelectromechanical systems (MEMS) technology has experienced significant shifts in the market; for example, Infineon now produces MEMS microphones, and Bosch acquired Akustica, a pioneering MEMS microphone company.
Despite their outwardly comparable appearances, the Infineon component and the Knowles component incorporate distinct internal designs and manufacturing processes.
Due to increased production volume and broader availability, microelectromechanical systems (MEMS) technology has experienced significant shifts in the market; for example, Infineon now produces MEMS microphones, and Bosch acquired Akustica, a pioneering MEMS microphone company.
Despite their outwardly comparable appearances, the Infineon component and the Knowles component incorporate distinct internal designs and manufacturing processes.
Step 6
Die markings on the Infineon 1014 MEMS die demonstrate a high level of detail, reflecting a comparable membrane structure found in Knowles devices.
The available area allowed for ample maneuvering.
The available area allowed for ample maneuvering.
Step 7
Detailed examination of the Infineon 1014 ASIC's die photograph offers limited insight into its internal operational architecture.
A substantial metallic sheet covers the circuit board.
This metallic layer may function as an electrical ground, provide radio frequency shielding, or obscure the underlying die circuitry, a practice increasingly common due to the prevalence of device teardowns.
The ASIC die was successfully revealed by Chipworks, who were able to eliminate the metallic layer without issue.
A substantial metallic sheet covers the circuit board.
This metallic layer may function as an electrical ground, provide radio frequency shielding, or obscure the underlying die circuitry, a practice increasingly common due to the prevalence of device teardowns.
The ASIC die was successfully revealed by Chipworks, who were able to eliminate the metallic layer without issue.
Step 8
Knowles also supplied the S199 microphone, found within the iPhone 4's included headset, marking a second successful design partnership.
Because the microphones are positioned differently on each model, installation typically involves adapting the device to suit the specific use case.
Because the microphones are positioned differently on each model, installation typically involves adapting the device to suit the specific use case.
Step 9
Despite differing external packaging labels, the two microphones both utilize identical ASIC and MEMS die markings.
Step 10
The Knowles 1950 X-ray source is located on the left, while the Infineon 1014 X-ray source is positioned on the right.
Radiographic analysis reveals a striking resemblance between the Knowles 1950 and Infineon 1014 components; visual differentiation requires careful attention due to their near-identical appearance.
Radiographic analysis reveals a striking resemblance between the Knowles 1950 and Infineon 1014 components; visual differentiation requires careful attention due to their near-identical appearance.
Step 11
This is the Knowles S199 X-ray system.The replacement component exhibits significantly different characteristics compared to both the Knowles and Infineon versions.
Image documentation for this disassembly was generously supplied by Chipworks.
Image documentation for this disassembly was generously supplied by Chipworks.