1 Application note
sonitron Piezo Audio Speakers & Amplifiers
are the perfect answer for audio sound, voice
messages and complex audio information into
When there is no place ….”a piezo speaker feels
comfortable”. “Perfect fit” and “slim line” are the
words you can add to your design.
No more worries anymore about water drops that
can damage the front of your speaker. The
piezoelectric speakers of Sonitron embrace these
problems and nevertheless EMC/EMI is history.
Patented multilayer Technology
A few years ago piezoelectric speakers were only
known as piezo tweeters. Loudspeakers that are
able to produce only high audio frequencies,
typically from around 2 kHz to 20 kHz.
Sonitron, established in 1977 and European
leader in piezoelectric audio components, started
with intensive research to develop broadband
audio speakers who have a frequency response
graph beneath 1kHz.
Sonitron developed and patented a completely
new principle of piezoceramics and a composite
polymer/metal membrane. The composite
polymer/metal membrane reduces unwanted
resonance peaks to provide a more even
frequency response than can be achieved with
conventional designs. High sound quality and
low distortion quarantee perfect reproduction of
music and speech.
“ Polymer/ metal membrane”
"Piezo Speaker Technology, an answer to
your request..." Excellence in physical acoustics
Piezoelectric Speaker Technology sonitron Techpaper
The Basic Four of Piezoelectric
Piezoelectric speakers have a total different
working principle than an electro dynamic
speaker. There is no coil, no magnetic field and no
large current consumption.
“No electro-magnetic field (EMC/EMI)”
The heart of each piezoelectric speaker is a
ceramic disc that interacts when it feels a certain
An increase of the signal amplitude Vpp (Voltage
peak to peak), will result in a larger piezo
deformation and result in a larger sound output.
“Interacting with voltage variations”
“More Vpp creates more sound output”
Piezoelectric speakers have a complex electronic
equivalent circuit but mainly they can be seen as
a capacitive load with values between 10nF and
The capacitive value of the speaker is an
important characteristic for the amplifier circuit of
“Piezoelectric means capacitive load”
Most amplifier IC’s are developed for
electrodynamic speakers. They can deliver high
current variations and are limited to a voltage
level of +/- 10 Vpp.
Piezoceramic speakers demand voltage
variations. The current consumption is extreme
small and the voltage peak to peak level goes up
“Piezo Audio Amplifier is needed”