SENSOR SOLUTIONS
Rugged Miniature Silicon MEMS Microphone 
High temperature immunity permits fully automated SMT manufacturing

Infineon Technologies’ new Silicon Microphone SMM310 offers the same acoustic and electrical properties of conventional microphones but is half their size. Additionally, it is more heat resistant and more rugged than typical microphones based on Electret Condenser Microphone (ECM) technology.

This silicon MEMS (Micro Electro Mechanical System) microphone can withstand temperatures as high as +260°C and is very immune to vibrations and shocks. Thanks to its temperature resistance, it can be soldered to any standard PCB without difficulty and is thus ideally suited to fully automated manufacturing; its RoHS-compliant SMT (Surface Mount Technology) package can be reflow soldered.

The microphone consists of two chips, the MEMS chip and the Application Specific Integrated Circuit (ASIC); both share the same package on the SM device. The MEMS comprises a rigid, perforated back electrode and flexible silicon membrane and serves as a capacitor, transforming acoustic waves into capacity variations. The ASIC converts the variations into electrical signals and passes them to appropriate processing devices, such as a baseband processor or amplifier.



Current consumption is typically only 80μA for a power supply voltage range from 1.5V to 3.3V.

The SMM310 features excellent acoustic properties such as a high Signal-to-Noise Ratio (SNR) 59dB(A) and high sensitivity. Silicon MEMS microphones such as the SMM310 can be used in numerous applications including portable consumer and computing. Its compact, flat package (4.72mm x 3.76mm x 1.5mm) allows for a wide choice of product design options; several identical, individual microphones can be easily configured into the arrays needed for directional microphones, because silicon microphones’ variations over time are low and conformity is maintained.

Infineon is the only provider that offers, from a single source, MEMS and ASIC expertise with the associated manufacturing skills. The technology used to manufacture the MEMS microphones was developed by Infineon in Villach, Austria.

Features

  • SMD MEMS microphone for automated surface mount assembly
  • Reflow soldering up to +260°C (lead free)
  • High long-term temperature stability
  • Stable sensitivity over power supply range of 1.5V to 3.3V
  • Low current consumption of 80μA
  • Excellent power supply rejection of -55dB
  • High integrated immunity to EMI
  • RoHS-compliant package with small footprint and low height of 1.25mm

Applications

The SMM310 is designed for:

  • Mobile phones (handsets, headsets)
  • Consumer (game consoles, PDAs)
  • Computing (PCs, notebooks)
  • Cameras (digital still cameras, video cameras)

For further information, including the SMM310 Application Notes and a Promotional Video on MEMS, please click here