1
Multimedia ICs
KARAOKE echo IC
BU9253AS / BU9253FS / BU9255FS
The BU9253AS, BU9253FS and BU9255FS are single-chip ICs that contain all the components needed to configure
a KARAOKE echo system: an A / D and D / A converter, SRAM, LPF, and mixer for mixing source signals. With
these ICs, an echo function can be configured easily and with minimum external components.
•
Applications
KARAOKE functions for portable stereo sets, mini com-
ponent stereo sets, video CDs and DVDs, etc.
•
Features
1) Echo mixing ratio is adjustable with a DC voltage.
2) A second order LPF can be configured with the
internal amplifier and an attached capacitor and
resistor.
3) Delay time of 131ms. (when fCLK = 357kHz)
4) Internal mute function.
5) Single power supply (5V).
•
Block diagram
BU9253FS / BU9255FS
BU9253AS
1
COUNTER
VCC A / D
SRAM
D / A
OSC
2345678
16 15 14 13 12 11 10 9
MIX
123456789
COUNTER
VCC A / D
SRAM
D / A
OSC
16 15 14 13 12 11 10
MIX
18 17

+
–

+
–

+
–

+
–