MEMS Microphone - Sonion · Membrane Cover Substrate ASIC die MEMS die MEMS Microphone Document:...
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Membrane Cover Substrate ASIC die MEMS die MEMS Microphone Document: Sonion Academy Poster Doc code: 306 Version: 001 Release date: 2015-08-24 Sound inlet How it works 1 A sound wave enters the sound inlet and front volume of the microphone. 2 The ASIC inside the MEMS microphone uses a charge pump to place a fixed charge on the microphone membrane. 3 The rear volume of the microphone creates a pressure reference for the membrane. Incoming sound creates a pressure differ- ence between front and rear volume. This pressure difference moves the mem- brane of the MEMS die. 4 The ASIC then measures the voltage variations caused when the capacitance be- tween the membrane and the fixed backplate chang- es due to the motion of the membrane. 5 The amplifier converts the high impedance of the cart- ridge to a low impedance. Due to this the voltage swing at the output terminal represents the potential change at the membrane and is consequently proportional to the incoming sound level.
Transcript of MEMS Microphone - Sonion · Membrane Cover Substrate ASIC die MEMS die MEMS Microphone Document:...
Membrane
Cover
Substrate
ASIC die
MEMS die
MEMS Microphone
Document: Sonion Academy PosterDoc code: 306Version: 001Release date: 2015-08-24
Sound inlet
How it works
1 A sound wave enters the sound inlet and front volume of the microphone.
2 The ASIC inside the MEMS microphone uses a charge pump to place a fixed charge on the microphone membrane.
3 The rear volume of the microphone creates a pressure reference for the membrane. Incoming sound creates a pressure differ-ence between front and rear volume. This pressure difference moves the mem-brane of the MEMS die.
4 The ASIC then measures the voltage variations caused when the capacitance be-tween the membrane and the fixed backplate chang-es due to the motion of the membrane.
5 The amplifier converts the high impedance of the cart-ridge to a low impedance. Due to this the voltage swing at the output terminal represents the potential change at the membrane and is consequently proportional to the incoming sound level.
