YDA138
●Protection
Function
YDA138 has Over-current Protection function and Clock Stop Protection function as protection functions for the digital
amplifier. In addition, it has Output Current Limit function as a protection function for headphone amplifier. Moreover,
YDA138 has Thermal Protection function, Low-voltage Malfunction Prevention function, and Power Supply Voltage
Fluctuation Protection function commonly.
Over-current Protection Function
This is a function to make the Over-current Protection Mode (disables the output stage of digital amplifier in addition to the
output of L signal to PROTN terminal) by detection of short-circuiting (Ground short/Power supply short/Speaker terminal
short) in the output stage of digital amplifier.
The over-current protection function can be canceled by power off or setting L to SLEEPN terminal and can be
automatically returned after the over-current detection by connection of PROTN terminal and SLEEPN terminal.
Thermal Protection Function
This is a function to make the Thermal Protection Mode (disables the output stage of digital amplifier and headphone
amplifier in addition to the output of L signal to PROTN terminal) by detecting extraordinary high temperature of YDA138.
This Thermal Protection mode can be cancelled by lowering temperature of YDA138, power off, or setting L to SLEEPN
terminal and can be automatically returned after the extraordinary high temperature detection by connection of PROTN
terminal and SLEEPN terminal.
Clock Stop Protection Function
This is a function to make the Clock Stop Protection mode (disables the output stage of digital amplifier) when carrier clock
frequency was extraordinarily lowered in digital amplifier mode.
The Clock Stop Protection mode can be cancelled by returning carrier clock frequency to the right value.
Low-voltage Malfunction Prevention Function
This is a function to make the Low-voltage Protection mode (disables the output stage of digital amplifier and headphone
amplifier in addition to making “Hi-Z” of PROTN terminal) when voltage at 12V-line power terminal (PVDDREG)
becomes lower than Low-voltage detection threshold voltage (V
UVPL
) or voltage at 5V-line power terminal (REFA, DVDD)
becomes lower than the voltage (V
UVAL
).
In addition, when voltage at 12V-line power supply terminal becomes lower than V
UVPL,
5V embedded regulator is also
disabled.
The Low-voltage Protection mode is cancelled when voltage at each power supply terminal exceeded the low-voltage
cancellation threshold voltage (V
UVPH
,V
UVAH
).
Power Supply Voltage Detection Function
This is a function to make Mute mode when voltage at 5V Regulator output terminal (REFA) fluctuated (V
MH
,V
ML
) with
respect to twice of the voltage of reference terminals (VREFL,VREFR).
Headphone Amplifier Output Current Limit Function
YDA138 headphone amplifier has a Current-Limit-Circuit which limits output current so as not to exceed the limit current
(I
OCHP
).
●5V
Regulator Function
YDA138 outputs 5V to REFA terminal when SLEEPN terminal is H. Connect a 1µF or more capacitor to REFA terminal
for voltage stabilization.
Connect REFA terminal to DVDD terminal on a board. And, do not connect the REFA terminal to other terminals except
for DVDD terminal and YDA138 control terminals.
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YAMAHA [ YAMAHA CORPORATION ]
