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Multimedia ICs
Analog compander for KARAOKE
echo systems
BA7725S / BA7725FS
The BA7725S and BA7725FS are analog companders designed for KARAOKE echo systems, and logarithmically
compress the signal level by 1 / 2 and then logarithmically expand it by a factor of 2. These ICs can be used in com-
bination with the BU9252S or BU9252F to create a digital echo system. These ICs have an internal line mixer ampli-
fier for mixing line input and echo signals. The internal electronic volume control makes it possible to adjust the mixer
level and loop level mixer with an external DC voltage.
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Applications
Circuits that require analog signal compression and expansion
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Features
1) Internal logarithmic 1 / 2 compression circuit and 2 ·
expansion circuit
2) Internal 2-channel buffer amplifier used as a tertiary
low pass filter
3) Internal mixer amplifier that mixes line input and
microphone input
4) Internal electronic volume control allows for adjust-
ment of the echo mixer level and loop mixer level
using an external DC voltage.
5) Internal microphone amplifier and microphone input
ON / OFF switch
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Absolute maximum ratings (Ta = 25°C)
Parameter Symbol Limits Unit
Power supply voltage VCC 13 V
Power
dissipation
BA7725S 1000
* 1
mW
600
* 2
BA7725FS
Storage temperature °C
Operating temperature °C
– 55 ~ + 125
– 10 ~ + 70
Pd
Tstg
Topr
*
1 Reduced by 10mW for each increase in Ta of 1°C over 25°C.
*
2 Reduced by 6.0mW for each increase in Ta of 1°C over 25°C.
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Recommended operating conditions
Parameter Symbol Limits Unit
Power supply voltage VVCC 6.5 ~ 12.0