SPM0204LE5H Knowles Acoustics, SPM0204LE5H Datasheet - Page 26

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SPM0204LE5H

Manufacturer Part Number
SPM0204LE5H
Description
MICROPHONE, -38DB, OMNI
Manufacturer
Knowles Acoustics
Datasheet

Specifications of SPM0204LE5H

Transducer Function
Microphone
Device Type
Microphone
Directivity
Omni
Connector Type
SMD
Sensitivity
-38 ±3dB
Length
3.76mm
Supply Voltage
3.6V
Supply Voltage Max
3.6V
Supply Voltage Min
1.5V
Drain Current Max
250µA
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
26
MICROPHONES
Microphones measure sound pressure. Inside a Knowles microphone is a thin flexible diaphragm, an electrically
charged plate, and an amplifier (Fig. 1). The output voltage is proportional to changes in the small separation
between the diaphragm and the charged plate (Fig. 2).
As sound pressure inside the front cavity increases, the diaphragm is pushed closer to the plate. As the
pressure decreases, it moves further away. The motion of the diaphragm produces a small electrical signal that
is amplified by a miniature circuit inside the microphone.
The sensitivity of a typical Knowles’ microphone is measured in units of dB relative to 1 Volt per 0.1 Pascal.
Fig 1: Cross section of a Knowles EM microphone
FIG. 2: EM diaphragm and electret
MICROPHONE AND SPEAKER BASICS
MICROPHONE AND SPEAKER BASICS
AMPLIFIER
OUTPUT TERMINAL
CHARGE PLATE
CHARGE PLATE
DIAPHRAGM
DIAPHRAGM
www.knowles.com
FRONT CAVITY
AIR GAP SEPARATION
WIRE
SOUND PRESSURE

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