ET- 34018

ET- 34018
LINEAR INTEGRATED CIRCUIT
VOICE SWITCHED SPEAKERPHONE CIRCUIT
DESCRIPTION
The Contek KGM34018
speaker-phone integrated circuit
incorporates the necessary functions to produce a high quality
hands-free speaker-phone system. The applications include
household and office speaker-phones, intercom systems, hand
free kit for mobile phones, and others
SOP-28
FEATURES
*All necessary level detection and attenuation controls for a
hand-free telephone included.
*Background noise level monitoring with long time constant.
*Background sound level compensation for transmit and
DIP-28
receive levels as well as the background level.
*Wide operating dynamic range through signal compression.
*On-chip voltage regulators illuminate external regulators for
lining operation.
*Power audio amplifier for typical 100mW output (into 25
ohms)with peak limiting for speaker to minimize distortion.
*Chip Select pin for active/stand by operation.
*Volume control function for external volume control.
*Standard 28-pin plastic DIP and SOP package.
ABSOLUTE MAXIMUM RATINGS(Ta=25
PARAMETER
C,Voltages referred to pin 22)
V+ terminal Voltage (pin 16)
CS (pin 18
Speaker amplifier Ground(pin 14)
VLC(pin 24)
Storage temperature
RECOMMENDED OPERATION CONDITIONS
PARAMETER
V+ Terminal Voltage (pin 16)
CS (pin 18)
Vcc (pin 20)
VLC(pin 24)
Receive Signal(pin 27)
Microphone Signal(pin 9)
Speaker Amplifier Ground (pin 14)
Ambient Temperature
1
VALUE
UNIT
+12,-1.0
+12,-1.0
V
V
+3.0,-1.0
+VCC,-1.0
-65 ~ +150
V
V
C
VALUE
UNIT
+6.0 to +11
0 to +11
V
V
0 to 3.0
0.55VB to VB
0 to 250
0 to 5.0
-10 to +10
-20 to +60
mA
V
mVrms
mVrms
mVdc
C
BEIJING ESTEK ELECTRONICS CO.,LTD
ET- 34018
Internal Block Diagram
TRANSMIT
CHANNEL
MIC
TRANSMIT
OUTPUT
TRANSMIT
ATTENUATOR
MIC AMP
TRANSMIT
LEVEL
DETECTOR
SIGNAL/NOISE
DETECTOR
TRANSMIT/
RECEIVE
COMPARATOR
ATTENUATOR
CONTROL
SIDE
TONE
SIDE
TONE
RECEIVE LEVEL
DETECTOR
PEAK
LIMITER
SPEAKE
R AMP
RECEIVE
ATTENUATOR
RECEIVE
INPUT
RECEIVE
CHANNEL
VCC
REGULATOR
SPE
AKE
R
DC INPUT
TELEPHONE
LINE
Contek
ENABLE
INPUT
RECEIVE VOLUME
CONTROL
Fig 1
PIN CONFIGURATIONS
PIN
1
2
NAME
RR
RTX
3
4
TXI
TXO
5
TLI
6
TLO
7
RLI
8
RLO
9
MCI
10
11
MCO
CP1
12
CP2
13
XDI
14
SKG
15
SKO
16
V+
17
AGC
18
CS
19
20
21
SKI
VCC
VB
22
GND
DESCRIPTION
A resistor to ground provides a reference current for the transmit and receive attenuators
A resistor to ground determines the nominal gain of the transmit attenuator ,the transmit channel gain is
inversely proportional to RTX resistance.
Input to the transmit attenuator. Input resistance is nominally 5.0k ohms.
Output of the transmit attenuator. The TXO output signal drivers the input of transmit level detector, as well
as the external circuit which drivers the telephone line.
Input of the transmit level detector. An external resistor ac coupled to The TLI pin sets the detection level.
Decreasing this resistor increases the sensitivity to transmit channel signals.
Output of the transmit level detector. The external resistor and capacitor set the time the comparator will
hold the system in the transmit mode after speech ceases.
Input of the receive level detector. An external resistor ac coupled to The RLI pin sets the detection level.
Decreasing this resistor increases the sensitivity to receive channel signals
Output of the receive level detector. The external resistor and capacitor set the time the comparator will
hold the system in the receive mode after speech ceases
Microphone amplifier input. Input impedance is nominally 10k ohms and the dc bias voltage is
approximately equal to VB
Microphone amplifier output. The MIC amp gain is internally set at 34dB(50V/V)
A parallel resistor and capacitor connected between this pin and VCC holds a voltage corresponding
to the background noise level. The transmit detector compares the CP1 voltage with the speech signal from
A capacitor at this pin peak detects the speech signals for comparison with the background noise level held
at CP1.
Input to the transmit detector system. The microphone amplifier output is ac coupled to the XDI pin
through an external resistor
High current ground pin for the speaker amplifier output stage. The SKG voltage should be within
10mV of the ground voltage at pin 22
Speaker amplifier output. The SKO pin will source and sink up to 100mA when ac coupled to the
speaker. The speaker amplifier gain is internally set at 34dB(50V/V).
Input DC supply voltage. V+ can be powered from Tip and Ring if an ac decoupling inductor is used to
prevent loading ac line signals. The required V+ voltage is 6.0V to 11V(7.5V nominal ) at 7.0mA
A capacitor from this pin to VB stabilizes the speaker amplifier gain control loop, and additionally
controls the attack and decay time of this circuit. The gain control loop limits the speaker amplifier input
to prevent clipping at SKO. The internal resistance at AGC pin is nominally 110k ohms.
Digital chip select input. When at a logic "0" (<0.7V) the VCC regulator is enabled. When at a logic "1"
(>1.6V),the chip is in the standby mode drawing 0.5mA.An open CS pin is a logic "0". Input
Impedance is nominally 140k ohms. The input voltage should not exceed 11V
Input to the speaker amplifier. Input impedance is nominally 20k ohms
A 5.4V regulated output which powers all circuits except the speaker amplifier output stage
An output voltage equal to approximately VCC/2 which series as an analog ground for the
speakerphone system. Up to 1.5mA of external load current may be sourced from VB. Output
impedance is 250 ohms. A filter capacitor is required
Ground pin for the IC(except the speaker amplifier)
2
BEIJING ESTEK ELECTRONICS CO.,LTD
ET- 34018
(continued)
PIN
NAME
23
XDC
24
VLC
25
ACF
26
27
28
RXO
RXI
RRX
DESCRIPTION
Transmit detector output. A resistor and capacitor at his pin hold the system in the transmit mode during
pauses between words or phrases. When the XDC pin voltage decays to ground, the attenuators switch
from the transmit mode to idle mode. The internal resistor at XDC is nominally 2.6k ohms(see fig.1).
Volume control input>connecting this pin to the slider of a variable resistor provides receive mode
volume control. The VLC pin voltage should be less than or equal to VB
Attenuator control filter. A capacitor connected to this pin reduces noise transient as the attenuator
control switches level of attenuation
Output of the receive attenuator. Normally this pin is ac coupled to the input of the speaker amplifier
Input of the receive attenuator. Input impedance is nominally is 5.0k ohms
A resistor to ground determines the nominal gain of the receive attenuator. The receive channel gain is
directly proportional to the RRX resistance
ELECTRICAL CHARACTERISTICS(referred to fig. 1)
PARAMETER
SUPPLY VOLTAGES
SYMBOL
V+ Supply Current
IV+
V+=11V, Pin 18=0.7V
V+=11V, Pin 18=1.6V
VCC Voltage (V+=7.5V)
Line
Regulation (6.5V<V+<11V)
Output Resistance (ICC=3mA)
VB Voltage(V+=7.5V)
Output Resistance (I B=1.7mA)
ATTENUATORS
Receive Attenuator Gain (1.0kHz)
Rx Mode, Pin 24= VB, Pin 27 =
250Mvrms
Range (Rx to Tx Modes)
Idle Mode, Pin 27= 250mVrms
RXO Voltage (Rx Mode)
Delta RXO Voltage (Switch from Rx
to Tx Mode)
RXO Sink Current (Rx mode)
MIN
UNIT
9.0
800
5.9
150
20
300
3.3
mA
A
Vdc
MV
ohms
mV
Vdc
ohms
4.9
GRX
2.0
6.0
10
dB
GRX
GRI
VRXO
VRXO
40
-20
1.8
44
-16
2.3
48
-12
3.2
100
dB
dB
mV
mV
2.5
IRXOL
75
ITXOH
1.0
TXO Input Resistance
ACF Voltage (VCC-Pin 25 Voltage)
Rx Mode
Tx Mode
Idle Mode
RTXI
VACF
3.5
5.4
65
6.0
80
2.9
250
MAX
Vcc
VccLN
RoVcc
Vccsat
Vb
Rovb
TXO Source Current (Tx mode)
SPEAKER AMPLIFIER
Speaker Amp Gain (pin 19 = 20mVrms)
SKI Input Resistance
SKO Voltage ( Pin 19 =Cap couple
to GND)
SKO High Voltage ( Pin 19 = 0.1V,
-60mA Load at Pin 15)
SKO Low Voltage (pin 19=0.1V,
+60mA Load at Pin 15)
MICROPHONE AMPLIFIER
Microphone Amp Gain
( Pin 9 = 10mVrms,1KHz)
Microphone Amp Input Resistance
LOGAMPS
RLO Leakage Current (Pin 8 = VB+1.0V)
TLO Leakage Current (Pin 6 = VB+1.0V)
Transmit-Receive Switching
Threshold (Ratio of ITLI to IRLI - at
20 A - to Switch Tx-Rx Comparator)
TRANSMIT DETECTOR
XDC Voltage
Idle Mode
Tx Mode
CP2 Current Source
Distortion
Rx Mode
RXI to SKO
(pin 27 = 10mVrms,1KHz)
Tx Mode
MCI to TXO
(Pin 9 = 5mVrms,1KHz)
TYP
A
5.0
3.0
mA
8.0
k
150
6.0
75
GSPK
RSKI
VSKO
33
15
2.4
VSKOH
5.5
mV
mV
mV
34
22
3.0
35
37
3.6
dB
k
Vdc
Vdc
VSKOL
600
mV
GMCI
32.5
34
35
dB
RMCI
6.5
10
16
k
2.0
2.0
A
A
ILKRLO
ILKTLO
ITH
25
VXDC
ICP2
5.0
0
4.0
10
Vdc Vdc
13
A
RXD
1.5
%
TXD
2.0
%
Note 1:V+=7.5V, CS =0.7V except where noted.
Note 2:Rx mode:pin7=-100 A, pin5=+100 A, except where noted
Tx mode: pin 5,13=-100 A, pin 7=+100 A, pin 11=0V. Idle mode: Pin 5=-100A, pin 7,13=+100 A
Note 3:Current into a pin designed as + ,current out of a pin designed -;
Note 4:Voltage referred to pin 22,Tamb=25 C
3
BEIJING ESTEK ELECTRONICS CO.,LTD
ET- 34018
TEMPERATURE CHARACTERISTICS(-20 TO +60 C )
PARAMETER
V+ Supply Current ( V+ 11V,Pin 18 = 0.7V )
V+ Supply Current(V+ 11V,Pin 18 = 1.6V )
VCC Voltage( V+ = 7.5V )
Attenuator Gain ( Max and Min Setting )
Delta RXO,TXO Voltage
Speaker AMP Gain
Microphone AMP Gain
Microphone Amp Input Resistance
Tx-Rx Switching Threshold (20 A)
PIN
TYP CHANGE
UNIT
16
16
20
-0.2
-0.4
+0.1
+-0.003
+-0.24
+-0.001
+-0.4
+0.4
+-0.2
%/ C
%/ C
%/ C
dB/ C
%/ C
dB/ C
dB/ C
%/ C
nA/ C
4,26
15,19
9,10
9
5,7
S1
0.01μF
22kΩ
1000μF
4700pF 4700pF
47kΩ
2.2kΩ
33kΩ
10μF
47kΩ
0.1μF
470kΩ
0.068μF 15kΩ
R
8.2kΩ
6.8kΩ
8.2kΩ
8.2kΩ
0.01μF
0.01μF
2.7kΩ
47kΩ
T
470kΩ
68kΩ
Hook
Switch
0.05μF
470kΩ
220kΩ
0.01μF
4.7kΩ
47kΩ
Vcc
0.05μF
MIC
2kΩ
0.1μF
10
ΤXΙ
ΜCΟ
9
MCI
15
SKO
14
SKG
13
XDΙ
4
0.1μF
0.068μF
1.0μF
4.7μF
100kΩ
4.7kΩ
3
0.068μF
0.1μF
S2
0.068μF
VB
3.3kΩ
47μF
3.3kΩ
5
11
25
17
16
18
7
TXO
TLI
CP1
ACF
AGC
V+
CS
RLI
27
RTX
RR
RRX
RXO
SKI
CP2
XDC
TLO
1
28
26
19
12
23
6
RXI
47μF
2
4.3kΩ
VB
47μF
30kΩ
18kΩ
0.01μF
91kΩ
20kΩ
Volume
Control
47μF
24kΩ
200kΩ
RLO
GND
8
2.2MΩ
22
2.2MΩ
1.0μF
20
1.0μF
Vcc
21
4.7μF
VB
24
4.7μF
VLC
0.05μF
Speaker
Fig 2 - Basic Line powered Speakerphone
4
BEIJING ESTEK ELECTRONICS CO.,LTD