YDA138
●Headphone Amplifier Function
YDA138 has class AB single-ended push-pull headphone amplifier. Headphone amplifier mode can be set by setting HP
terminal to H. Audio signal input terminal and voltage reference terminal is common to digital amplifier.
Connect DC-cut capacitor to headphone amplifier output terminal (HPOL and HPOR).
When a headphone amplifier is not used, HP terminal should be "L" and output terminal (HPOL, HPOR) should be "No
Connection".
First stage Amplifier Gain Setting function
Headphone amplifier is composed of the first stage amplifier of which gain setting is possible, and 0dB fixed-gain
amplifier. Gain of the first stage amplifier can be set by VOL[1:0] terminal.
Headphone Amplifier Gain Setting
VOL[1:0]
Gain
L,L
18dB
L,H
12dB
H,L
6dB
H,H
0dB
Input sensitivity
Input Impedance
0.14V
12.1kΩ
0.28V
22.0kΩ
0.56V
37.1kΩ
1.12V
56.5kΩ
●Control Function
Sleep Function
When SLEEPN terminal is L, YDA138 enters the Sleep Mode.
In Sleep mode, all the circuit functions including 5V regulator are stopped to minimize the consumption current. At this
time, output stages of digital amplifier and headphone amplifier are disabled and PROTN and CKIO terminal output
becomes “Hi-Z”.
Mute Function
When MUTEN terminal is set to L while HP terminal is L, YDA138 enters the Digital Amplifier Mute mode. In this mode,
output stage of Digital Amplifier is disabled.
When MUTEN terminal is set to L while HP terminal is H, YDA138 enters the Headphone Amplifier Mute Mode. In this
mode, output stage of Headphone Amplifier outputs the reference voltage.
Headphone Selection Function
When HP terminal is set to H, YDA138 enters the Headphone Amplifier mode. At this time, output stage of Digital
Amplifier is disabled. On the contrary, when HP terminal is set to L, YDA138 enters Digital Amplifier mode. At this time,
output of the Headphone Amplifier output is disabled.
When logic of HP terminal is changed, YDA138 restarts and as the result of it, all the protection states are cleared.
Monaural Selection Function
YDA138 enters the Monaural mode, when connecting VREFR terminal to REFA terminal and then connecting INR
terminal to AVSS terminal.
In Digital Amplifier Monaural Ｍode, maximum continuous output 20W can be obtained by short-circuiting between
OUTPL terminal and OUTPR terminal and between OUTML terminal and OUTMR terminal to drive 4Ωload resistor.
In Headphone Amplifier Monaural Mode, HPOUTL terminal outputs signals and HPOUTR terminal is disabled.
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YAMAHA [ YAMAHA CORPORATION ]
