YAC523 Datasheet, PDF (5/16 Pages) YAMAHA CORPORATION – Electric Variable Resistance 2

YAC523
■Description of functions
●Analog functions
・Maximum input voltage
The maximum amplitude of the input signal that is inputted to the analog input pin of YAC523 is 4.2Vrms when
power supply voltage is ±6V.
For a system to which a signal exceeding the power supply voltage (AVDD/AVSS) may be applied, use external
diodes to suppress the signal to the maximum rating or less.
・Maximum output voltage
The maximum output voltage(THD<1％) of the signal that is outputted from the analog output pin of YAC523 is
4.2Vrms when power supply voltage is ±6V and no load is connected. The output impedance is 100Ω (typ.).
●Realization of low residual noise system
General audio amplifiers are designed to have input sensitivity of approximately 150mV, and have a gain of
approximately 16dB at the preamplifier (PreAMP) section and approximately 30dB at the main amplifier section
(MainAMP).
The residual noise of YAC523 (Gain=-∞) is 1.2μVrms (typ.) which is very small, and the device has positive side
gain (max: 31.5dB). Therefore, by using YAC523 also as ”PreAMP”, systems with a very small residual noise
and amplification of volume control noise can be configured.
For conventional configurations that need a ”PreAMP”, even if the residual noise of the volume control itself is
zero, the noise that is produced at the ”PreAMP” is amplified by the gain, the noise becomes very high when it is
heard at the speakers.
When the input converted noise of ”PreAMP” is 1μV, the conventional configuration produces noise of
approximately 200μV at the speakers. For the configuration that uses YAC523, the noise is 38μV which is very
small.
Residual noise produced by
conventional configuration
Residual noise produced by a
configuration that adopts YAC523
1μVrms 6.3μVrms 200μVrms
+16dB
+30dB
Zin=50kΩ
1.2μVrms
YAC523
38μVrms
+30dB
Volume
PreAMP MainAMP
-∞〜+16dB
Volume + PreAMP
MainAMP
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