YDA131 Datasheet, PDF (12/18 Pages) YAMAHA CORPORATION – D- 1 STEREO 2.5W DIGITAL AUDIO POWER AMPLIFIER

■Application notes
YDA131
Warning for the device which makes sound using speaker.
A speaker radiates heat in a voice-coil by air flow accompanying vibration of a diaphragm. When DC signal
(several Hz or less) is input, heat radiation characteristics falls rapidly.
In addition, even if it is used lower than rated input, it may lead to voice-coil burnout, smoke or ignition of a speaker.
In order to avoid such situations, be sure to implement one or more preventive measures from the following.
1) Do not select settings (sound creation, sound generation stop with DC offset) which may generate DC signal.
(Since thoroughness of this preventive measure is generally difficult, we recommend the combined use with
the following 2, 3 and 4)
2) Add the equivalent of DC cut digital filter for cutting DC signal in the digital section.
(As long as "Built-in" is not mentioned in the manual, there is no such built-in circuit inside of a device).
3) Add a DC cut capacitor for cutting DC signal in the analog section.
(When addition is specified in the example of a recommended circuit diagram, be sure to add)
4) When a latter stage device exists in the signal path from this device to speaker, be sure to realize the DC cut in a latter
stage device.
In addition, the above-mentioned measures are based on the assumption that the device itself, DC cut capacitor, and the
latter stage device will be in a normal operation. Therefore, it is also necessary to implement measures based on the
assumption of these part failures.
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