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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.

Circuits that require analog signal compression and expansion

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

Parameter

Symbol

Limits

Unit

Power supply voltage

13

V

Power

dissipation

BA7725S

mW

BA7725FS

Storage temperature

°C

Operating temperature

°C

– 55 ~ + 125

– 10 ~ + 70

Pd

Tstg

Topr

Parameter

Symbol

Limits

Unit

Power supply voltage

V

6.5

∼ 12.0