YDA144 Datasheet, PDF (5/26 Pages) YAMAHA CORPORATION – STEREO 2.1W Non-Clip DIGITAL AUDIO POWER AMPLIFIER

YDA144
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■Description of operating functions
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●Digital Amplifier Function
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YDA144 has digital amplifiers with analog and digital input, PWM pulse output, Maximum output of 2.1W(R_L=4Ω)×2ch.
Distortion of PWM pulse output signal and noise of the signal is reduced by adopting “Pure Pulse Direct Speaker Drive
Circuit”
In addition, YDA144 has been designed so that high-efficiency can be maintained within an average power range (100mW
or so) that is used for mobile terminal.
First Stage Amplifier Gain Setting Function
G0 terminal can set the Gain of YDA144. When Non-Clip function is disabled, the relation between G0 terminal setting and
Gain is as follows.
Digital Amplifier Gain Setting
G0
Gain
Input Impedance(Z_IN)
L
12dB
44kΩ
H
18dB
28kΩ
Note） H and L indicates logic High and logic Low, respectively.
Input Lch differential input signals to INL+ terminal and INL- terminal through DC-cut capacitors (C_IN). For single ended
operation, input the signal to INL+ pin through the DC-cut capacitor (C_IN). At this time, INL- pin must be connected to
AVSS pin through a capacitor (C_REF: same value as C_IN). As with Lch, connect input signals to Rch.
＜Differential input＞
＜Single input＞
In addition, positive (+) and negative (-) sides of differential input pins (INL+ and INL-, or INR+ and INR-), input pins of
the unused channel side, should be connected to each other and connected to AVSS through a capacitor.
Use a capacitor with the same capacitance (0.1µF) as that of a DC-cut capacitor in the channel side being used.
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＜Input terminal processing of unused channel side＞
The lower cut-off frequency (fc) can be found from DC-cut capacitor (C_IN) and input impedance (Z_IN) as shown below.
fc=1/(2ñπñZ_INñC_IN)
In order to reduce pop-noise, impedance in the differential input signal source is arranged. And, DC-cut capacitor (C_IN)
should be 0.1µF or less.
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