KA8512
COMPANDOR
INTRODUCTION
Compandor is a composite word of compressor and expander.
It is used for maintaining dynamic range and improving
of S/N ratio, and generally called as a noise reduction
system or automatic gain control system.
KA8512 consists of compressor, expander, mic amp,
Iimiter, ALC(automatic level control) and mute logic.
14-DIP-300
FEATURES
•
•
•
•
Operating voltage range : 2 ~ 6V
Included ALC circuit
Easy gain control to use external component
Included mute function
14-SOP-225B
ORDERING INFORMATION
Device
KA8512
KA8512D
Package
14-DIP-300
14-SOP-225B
Operating Temperature
-20°C ~ + 70°C
BLOCK DIAGRAM
EPI
ERC
EMUTE
CMUTE
2
15K
3
RECTIFIER
30K
5
6
MUTE LOGIC
10K
GAIN CELL
G
10K
_
4
V
REF
+
SUM AMP
+
LIMITER
V
REF
_
24K
30K
10K
15K
GAIN CELL
G
ALC
15K
+
MIC AMP
51K
EO
+
CO
V
REF
3.3K
12
_
125K
125K
_
30K
9
8
11
CPI-
CPI+
AGIC
13
ALC
BIAS CIRCUIT
RETIFIER
7
GND
14
V
CC
1
V
REF
10
CRC
KA8512
COMPANDOR
PIN CONFIGURATION
V
R E F
EPI
ERC
EO
EMUTE
CMUTE
GND
1
2
3
4
5
6
7
KA8512
14
13
12
11
10
9
8
V
C C
ALC
CO
AGIC
CRC
CPI-
CPI+
PIN DESCRIPTION
Pin No
1
Symbol
V
REF
Description
It is a voltage reference (V
REF
=1V) used for supplying a constant voltage
to the compressor and expander of compandor.
It is SUM AMP input terminal of expander. The voice signal recoverd after
2
EPI
the demodulation waveform from the receiver passed through the 2’ order
nd
low pass filter enters this terminal.
This terminal is used for converting waveform from the full wave rectifier to
3
ERC
DC element at the rectifier block of expander
(R X C = 22msec)
4
EO
It is an output terminal of expander, which a regenerated voice signal
comes out.
It is an expander mute terminal of compandor and the final mute block
of an expander located next to the receiver terminal. It blocks the data sig-
5
EMUTE
nal of MICOM being transmitted to an user, and is connected to the RX
mute terminal of MICOM.
Expanding is executed if this terminal is high, and expander mute is exe-
cuted if it is low.
KA8512
COMPANDOR
PIN DESCRIPTION
(Continued)
Pin No
Symbol
Description
It is compressor mute terminal of a compandor.
Mute block is used to avoid duplication of data transmission from MICOM
6
CMUTE
(Between the base and hand set) with the voice signal.
It is connected to the TX mute terminal of MICOM.
Compressing is executed if the terminal is high, and compressor mute is
executed if it is low.
7
8
GND
CPI+
It is ground terminal.
It is a MIC AMP non-inverting input terminal of compressor, and is used
as an input terminal for voice signal.
It is a MIC AMP inverting input terminal of compressor, and is used for
9
CPI-
adjusting the negative feedback loop gain.
(In application, gain is about 5)
This terminal is used for converting waveform from the full wave rectifier
10
CRC
to DC element at the rectifier block of compressor.
(R X C = 22msec)
This terminal is used for bypassing an AC element at the feed-back loop
11
AGIC
which comes from the SUM AMP block of compressor. A capacitor should
be connected between this terminal and GND.
12
CO
It is a compressor output terminal of compandor, and is connected to the
modulation input terminal of transmitter.
It is a reference voltage input terminal of ALC (Automatic Level Control).
ALC circuit may be turned off according to the ALC reference voltage, ma-
13
ALC
gnitude of output voltage may be limited if it is used for adjusting THD of
output voltage of compressor to less than 3% or to limit the frequency of
TX in case the input is higher than a certain level.
14
V
CC
It is supply voltage terminal.
KA8512
COMPANDOR
ABSOLUTE MAXIMUM RATINGS
Characteristic
Maximum Supply Voltage
Power Dissipation
Operating Temperature
Storage Temperature
Symbol
V
CC(MAX)
P
D
T
OPR
T
STG
Value
7
600
- 20 ~ + 70
- 55 ~ + 150
Unit
V
mW
°C
°C
ELECTRICAL CHARACTERISTICS
(V
CC
= 3V, f = 1KHz, Ta = 25°C, Unless otherwise Specified)
Characteristic
DC Electrical Characteristics
Operating Voltage
Operating Current
Compressor Part
Reference Voltage
Standard Output Voltage
V
REF
V
O(COMP)
∆
G
V1(COMP)
∆
G
V2(COMP)
THD
COMP
ATT
MUTE
V
LIM(COMP)
V
ALCO
No Signal
V
INC
= 13mVrms
= 0dB
V
INC
= -20dB
V
INC
= -40dB
V
INC
= 0dB
V
INC
= 0dB
V
INC
= Variable
V
ALC
= 0.87V
-0.5
-1.5
-
60
1.15
280
0
0.7
0.5
80
1.35
325
+0.5
0
1.0
-
1.5
360
dB
dB
%
dB
V
P-P
mVrms
0.9
240
1.0
300
1.1
340
V
mVrms
V
CC
I
CC
No Signal
-
2.0
-
-
3.6
6.0
6.0
V
mA
Symbol
Test Conditions
Min
Typ
Max
Unit
Gain Difference
Output Distortion
Mute Attenuation Ratio
Limiting Voltage
ALC
Expander Part
Standard Output Voltage
V
O(EXP)
∆
G
V1(EXP)
V
INE
= 180mVrms
= 0dB
V
INE
= -10dB
V
INE
= -20dB
V
INE
= -30dB
V
INE
= 0dB
V
INE
= 0dB
V
INE
= Variable
110
+1.0
-1.5
-1.5
-
60
500
130
+0.5
-0.7
0
0.5
85
600
160
0
0
+1.5
1.5
-
-
mVrms
dB
dB
dB
%
dB
mVrms
Gain Difference
∆
G
V2(EXP)
∆
G
V3(EXP)
Output Distortion
Mute Attenuation Ratio
Maximum Output Voltage
THD
EXP
ATT
MUTE
V
OEXP(MAX)
COMPANDOR
VI(COMP)
V
O (C OM P)
Vcc
10K
1uF
10uF
47K
22uF
2.2uF
9.1K
0.47uF
0.047uF
680
14
13
12
11
10
Rectifier
9
8
125K
+
V
RE F
125K
MUTE
Limiter
Bias
Circuit
Gain Cell
G
10K
10K
V
RE F
Rectifier
15K
_
15K
ALC
15K
Gain Cell
G
51K
10K
30K
_
Sum Amp
+
V
RE F
30K
24K
+
Mic Amp
_
3.3K
30K
_
MUT E
+
Sum Amp
1
2
0.047uF
33uF
3
4
1uF
2.2uF
10K
5
6
7
SW1
SW2
TEST CIRCUIT
KA8512
V
I (E X P )
V
O(E XP )
PCB Design
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