三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM7181
ECHO
DESCRIPTIONS
SM7181 is an Audio Echo Processor using
CMOS Technology. It has buildin AD/DA and
8KBits SRAM for echo effect time delay.
FEATURE
* Buildin adjustable OSC.
* Buildin power on reset circuit.
* Buildin 8KBits SRAM for delay control.
* By change oscillator resistor to echo effect
time.
APPLICATIONS
*
*
*
*
*
VCD
Karaok
TV
Audio System
Car Stereo
VREF
OSC1
OSC2
VDD
DGND
AGND
ADCTL
DACTL
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
OP1-IN
OP1-OUT
ADC-OUT
ADC-IN
DAC-IN
DAC-OUT
OP2-IN
OP2-OUT
Page 1
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM7181
ECHO
PIN DESCRIPTION
PIN No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
PIN NAME
VREF
OSC1
OSC2
VDD
DGND
AGND
ADCTL
DACTL
OP2-OUT
OP2-IN
DAC-OUT
DAC-IN
ADC-IN
ADC-OUT
OP1-OUT
OP1-IN
I/O
AI/O
IN
OUT
Power
Power
Power
AIN
AIN
AOUT
AIN
AOUT
AIN
AIN
AOUT
AOUT
AIN
FUNCTION
Analog referance voltage
Oscillator control Resistor
Power
Digital negative power supply
Analog negative power supply
ADC control
DAC control
OP2 output
OP2 input
DAC OP output
DAC OP input
ADC OP input
ADC OP output
OP1 output
OP1 input
AIO: Analog input/output
AIN: Analog input
AOUT: Analog output
Page 2
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM7181
ECHO
BLOCK DIAGRAM
D
A
C
T
L
D
A
C
I
N
D
A
C
O
U
T
A
D
C
O
U
T
A
D
C
I
N
A
D
C
T
L
OP1-IN
OP2-IN
Low Pass
Filter
Mix
AD Converter
VDD
DGND
OP1-OUT
OP2-OUT
Low Pass
Filter
AGND
DA Converter
OSC1
OSC
OSC2
Verf
POR
Digital
Control
SRAM
VREF
Page 3
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM7181
ECHO
Echo Mode & Surround Mode
SM7181 digitize the audio signal through A/D converter and store the value in a First-in- First-out 8Kbits
SRAM. After 3.2RCms of delay time the value store in the SRAM will be read out and reconstruct by
D/A converter then add with the present sound to become an echo signal output. The echo delay is
control by the RC of Pin 2, Pin 3.
Audio
out
Low Pass
Filter
Audio In
Add
Low Pass
Filter
DA Converter
Echo Mode
AD Converter
SRAM
ABSOLUTE MAXIMUM RATINGS
( Ta = 25 C, unless otherwise noted )
o
Symbol
Vcc
Icc
Pd
Topr
Tstg
Description
Supply voltage
Supply current
Power dissipation
Operation temperature
Storage temperature
Limits
6.5
100
1.7
-20
-25
75
125
Unit
V
mA
W
o
o
C
C
Page 4
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM7181
ECHO
AC CHARACTERISTICS
( Vcc = 5.0V, f
in
= 1KHz, Vi = 100mVrms, f
ck
= 4MHz, Ta = 25 C, unless
otherwised noted )
SYMBOL
Icco
Gv
Vomax
THD
No
o
PARAMETER
Sypply current
Voltage gain
Maximum output
voltage
Output disortion
Test condition
Min Typ Max Unit
60
100
2.5
mA
dB
Vrms
3.0
1.0
-60
-70
-25
%
%
dBV
dBV
dB
RL = 47K
Ω
THD = 10%
30KHz
L.P.F.
DIN
Audio
Echo mode
Surround mode
Echo mode
Surround mode
0.7
-0.5
1.2
1.5
0.3
-85
-90
-40
515 520
122 127
Output noise voltage
Power supply
rejection ratio
Mute time
Vcc = -20dBV
f = 100Hz
Echo mode
Surround mode
PSRR
Tmute
525
msec
132
msec
DC CHARACTERISTICS
Symbol
Vcc
Icc
V
IH
V
IL
Parameter
Supply voltage
Supply current
"H" input voltage
"L" input voltage
3V
1.5V
Limits
Min Typ Max
4.5
5
60
5.5
100
Unit
V
mA
V
V
Page 5
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