YDA137 Datasheet, PDF (10/20 Pages) YAMAHA CORPORATION – D- 2 STEREO 5W DIGITAL AUDIO POWER AMPLIFIER

YDA137
●Output Mute Function
When /MUTE terminal is L, it enters the Mute Mode. When /MUTE terminal is H, it enters normal operation condition.
In Mute Mode, consumption current can be decreased and setting and release can be performed in an instant.
In the mode, digital amplifier output terminal becomes WL, and headphone amplifier output terminal becomes RF.
In addition, Over-Current Detection Function stops in the mode.
Mute Mode in YDA137 points out the state where changed the inside of IC into the standby state, and output disabled.
For this reason, minute pop noise may occur under the influence of output offset voltage.
●Pop Noise Rejection Function
A function to reject pop noise caused by power-on, power-off, Sleep Mode setting, and its cancellation is equipped.
In power-on, YDA137 operates the start-up sequence after supply voltage (VDDL, VDDR) surpasses each threshold
voltage for low voltage malfunction prevention (VUVH). In the start-up sequence, pop noise can be rejected, because the
Mute Mode is canceled after input signal terminal (INL, INR) potential and voltage reference terminal (VREFL,
VREFR) potential have been stable sufficiently (after the Starting-time has elapsed).
Also in the cancellation of the Sleep Mode, pop noise can be rejected by the start-up sequence as well as that in the
power-on.
When a power supply is power-off, a pop noise is rejected by detect power supply change and mute output.
It is necessary to set each value to these elements to operate Pop Noise Rejection Function effectively in the power-on.
The values are found by the following formula, with a capacitance value (CREF) for VREFL terminal and VREFR
terminal, a resistor value (RI) and capacitance value (CI) for INL terminal and INR terminal.
CREF ≧ RI × CI / 5000 (Input sensitivity=150mVrms) CREF is recommended to 10μF.
CREF ≧ RI × CI / 22000 (Input sensitivity=1Vrms)
CREF is recommended to 10μF.
●Malfunction Prevention Function for Low Voltage
This is a function to stop the operation to prevent malfunction when supply voltage falls for some reason.
In YDA137, operation stops when supply voltage falls to operation stop voltage (VUVL) or lower.
In addition, operation starts again, when supply voltage goes up to start-up voltage (VUVH) or over.
●Malfunction Prevention Function for Power Supply Fluctuation
This is a function to prevent malfunction when supply voltage fluctuates falls rapidly for some reason.
In the digital amplifier output, it enters the Mute Mode to prevent a malfunction when supply voltage falls/rises to the
fall fluctuation protection voltage (VML) or lower, or the rise fluctuation protection voltage (VMH) or over. Moreover, in
the headphone output, it enters the Mute Mode to prevent it when supply voltage rises to VMH or over, and headphone
output stage becomes WL to prevent a malfunction, when supply voltage falls to VML or lower.
●Monaural Output Function
When /MONO terminal is L, it enters the Monaural Mode. When H, it enters the stereo mode.
In the Monaural Mode, input signal is input from L channel input terminal and is output from L channel output terminal.
At this time, R channel output terminal becomes unfixed.
In addition, when YDA137 is used only a monaural output (L channel) fixes, the following change is made to the
application circuit example.
It is not necessary to connect each resistance, the capacity, and the coil for filters of the R channel side.
Terminal processing when use by monaural output fixation.
Pin No. Name
Terminal processing
Pin No.
3 /MONO Connect to ground
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15 VSSR Connect to ground
21
16 VREFR Non connection
22
17 INR
Non connection
23
18 VPR
Non connection
24
19 HPOR Non connection
25
Name
VSSPR1
OUTMR
VDDPR
OUTPR
VSSPR2
VDDR
Terminal processing
Connect to ground
Non connection
Connect to 5V power supply
Non connection
Connect to ground
Connect to 5V power supply
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