UTC MC34018 LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
1
QW-R108-006,A
VOICE SWITCHED
SPEAKER-PHONE CIRCUIT
DESCRIPTION
The UTC MC34018 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.
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
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.
DIP-28
SOP-28
ABSOLUTE MAXIMUM RATINGS
(Ta=25
C
,Voltages referred to pin 22
)
PARAMETER VALUE
UNIT
V+ terminal Voltage (pin 16)
+12,-1.0
V
CS
(pin 18)
+12,-1.0 V
Speaker amplifier Ground(pin 14)
+3.0,-1.0
V
VLC(pin 24)
+VCC,-1.0
V
Storage temperature
-65 ~ +150
C
RECOMMENDED OPERATION CONDITIONS
PARAMETER VALUE
UNIT
V+ Terminal Voltage (pin 16)
+6.0 to +11
V
CS
(pin 18)
0 to +11
V
Icc(pin 20)
0 to 3.0
mA
VLC(pin 24)
0.55VB to VB
V
Receive Signal(pin 27)
0 to 250
mVrms
Microphone Signal(pin 9)
0 to 5.0
mVrms
Speaker Amplifier Ground (pin 14)
-10 to +10
mVdc
Ambient Temperature
-20 to +60
C
UTC MC34018 LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
2
QW-R108-006,A
BLOCK DIAGRAM
MIC AMP
TRANSMIT
ATTENUATOR
SIGNAL/NOISE
DETECTOR
ATTENUATOR
CONTROL
TRANSMIT/
RECEIVE
COMPARATOR
TRANSMIT LEVEL
DETECTOR
RECEIVE
ATTENUATOR
RECEIVE LEVEL
DETECTOR
SPEAKER
AMP
PEAK LIMITER
VCC
REGULATOR
SIDE TONE
NETWORK
RECEIVE
CHANNEL
TRANSMIT
CHANNEL
TRANSMIT
OUTPUT
RECEIVE INPUT
DC INPUT
RECEIVE VOLUME CONTROL
ENABLE INPUT
TELEPHONE
LINE
SIDE
TONE
MIC
SPEAKER
PIN CONFIGURATIONS
PIN NAME
DESCRIPTION
1
RR
A resistor to ground provides a reference current for the transmit and receive attenuators
2
RTX A resistor to ground determines the nominal gain of the transmit attenuator ,the transmit channel gain
is inversely proportional to RTX resistance.
3
TXI
Input to the transmit attenuator. Input resistance is nominally 5.0k ohms.
4
TXO Output of the transmit attenuator. The TXO output signal drivers the input of transmit level detcetor,
as well as the external circuit which drivers the telephone line.
5
TLI
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.
6
TLO 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.
7
RLI
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.
8
RLO 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.
9
MCI Microphone amplifier input. Input impedance is nominally 10k ohms and the dc bias voltage is
approximately equal to VB
10
MCO Microphone amplifier output. The MIC amp gain is internally set at 34dB(50V/V).
11
CP1 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 CP2.
12
CP2 A capacitor at this pin peak detects the speech signals for comparison with the background noise
level held at CP1.
13
XDI Input to the transmit detector system. The microphone amplifier output is ac coupled to the XDI pin
through an external resistor.
UTC MC34018 LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
3
QW-R108-006,A
(continued)
PIN NAME
DESCRIPTION
14
SKG High current ground pin for the speaker amplifier output stage. The SKG voltage should be within
10mV of the ground voltage at pin 22.
15
SKO 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).
16
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.
17
AGC 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.
18
CS
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.
19
SKI
Input to the speaker amplifier. Input impedance is nominally 20k ohms.
20
VCC A 5.4V regulated output which powers all circuits except the speaker amplifier output stage. VCC can
be used to power external circuitry such as a microprocessor(3.0mA max.) A filter capacitor is
required. The UTC MC34018 can be powered by a separate regulated supply by connecting V+ and
VCC to a voltage between 4.5V and 6.5V while maintaining
CS
at a logic "1".
21
VB
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.
22
GND Ground pin for the IC(except the speaker amplifier)
23
XDC 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).
24
VLC 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.
25
ACF Attenuator control filter. A capacitor connected to this pin reduces noise transient as the attenuator
control switches level of attenuation.
26
RXO Output of the receive attenuator. Normally this pin is ac coupled to the input of the speaker amplifier.
27
RXI Input of the receive attenuator. Input impedance is nominally is 5.0k ohms.
28
RRX 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 SYMBOL
MIN
TYP
MAX UNIT
SUPPLY VOLTAGES
V+ Supply Current
V+=11V,Pin 18=0.7V
V+=11V,Pin 18=1.6V
I
V+
9.0
800
mA
A
VCC Voltage(V+=7.5V)
Line
Regulation(6.5V<V+<11V)
Output Resistance(I
CC
=3mA)
Dropout Voltage(V+=5.0V)
Vcc
Vcc
LN
Ro
Vcc
Vccsat
4.9
5.4
65
6.0
80
5.9
150
20
300
Vdc
mV
ohms
mV
VB Voltage(V+=7.5V)
Output Resistance(I
B
=1.7mA)
Vb
Rovb
2.5
2.9
250
3.3
Vdc
ohms
UTC MC34018 LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
4
QW-R108-006,A
(continued)
PARAMETER SYMBOL
MIN
TYP
MAX UNIT
ATTENUATORS
Receive Attenuator Gain(1.0kHz)
Rx Mode, Pin 24= VB, Pin 27 =
250Mvrms
Range (Rx to Tx Modes)
Idle Mode, Pin 27= 250mVrms
G
RX
G
RX
G
RI
2.0
40
-20
6.0
44
-16
10
48
-12
dB
dB
dB
RXO Voltage (Rx Mode)
V
RXO
1.8 2.3 3.2 mV
Delta RXO Voltage (Switch from Rx
to Tx Mode)
V
RXO
100
mV
RXO Sink Current (Rx mode)
I
RXOL
75
A
RXO Source Current (Rx mode)
I
ROXH
1.0 3.0
mA
RXI Input Resistance
R
RXI
3.5 5.0 8.0 k
Volume Control Range (Rx
Attenuator Gain, Rx Mode,
0.6VB<Pin 24<VB
V
CR
24.5
32.5
dB
ATTENUATORS
Transmit Attenuator Gain (1.0kHz)
Tx Mode, Pin 3 = 250mVrms
Range, (Tx to Rx Mode)
Idle Mode, Pin 3 = 250Mvrms
G
TX
G
TX
G
TXI
4.0
40
-16.5
6.0
44
-13
8.0
48
-8.5
dB
dB
dB
TXO Voltage (Tx mode)
V
TXO
1.8 2.3 3.2 Vdc
Delta TXO Voltage (switch from Tc
to Rx Mode)
V
TXO
100
mV
TXO Sink Current (Tx mode)
I
TXOL
75
A
TXO Source Current (Tx mode)
I
TXOH
1.0 3.0 mA
TXO Input Resistance
R
TXI
3.5 5.0 8.0 k
ACF Voltage (VCC-Pin 25 Voltage)
Rx Mode
Tx Mode
Idle Mode
V
ACF
150
6.0
75
mV
mV
mV
SPEAKER AMPLIFIER
Speaker Amp Gain (pin 19 =
20mVrms)
G
SPK
33 34 35
dB
SKI Input Resistance
R
SKI
15 22 37 k
SKO Voltage ( Pin 19 =Cap couple
to GND)
V
SKO
2.4 3.0 3.6 Vdc
SKO High Voltage ( Pin 19 = 0.1V,
-100mA Load at Pin 15)
V
SKOH
5.5
Vdc
SKO Low Voltage (pin 19=0.1V,
+100mA Load at Pin 15)
V
SKOL
600 mV
MICROPHONE AMPLIFIER
Microphone Amp Gain ( Pin 9 =
10mVrms,1KHz)
G
MCI
32.5 34 35
dB
Microphone Amp Input Resistance
R
MCI
6.5 10 16
k
UTC MC34018 LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
5
QW-R108-006,A
(continued)
PARAMETER SYMBOL
MIN
TYP
MAX UNIT
LOGAMPS
RLO Leakage Current
(Pin 8 = VB+1.0V)
I
LKRLO
2.0
A
TLO Leakage Current
(Pin 6 = VB+1.0V)
I
LKTLO
2.0
A
Transmit-Receive Switching
Threshold (Ratio of I
TLI
to I
RLI -
at
20
A - to Switch Tx-Rx
Comparator)
I
TH
25
TRANSMIT DETECTOR
XDC Voltage
Idle Mode
Tx Mode
V
XDC
0
4.0
Vdc
Vdc
CP2 Current Source
I
CP2
5.0 10 13
A
Distortion
Rx Mode
RXI to SKO
(pin 27 = 10mVrms,1KHz)
R
XD
1.5
%
Tx Mode
MCI to TXO
(Pin 9 = 5mVrms,1KHz)
T
XD
2.0
%
Note 1:V+=7.5V,
CS
=0.7V except where noted.
Note 2:Rx mode:pin7=-100
A,pin5=+100A, except where noted.
Tx mode: pin 5,13=-100
A, pin 7=+100A, pin 11=0V.
Idle mode: Pin 5=-100
A, pin 7,13=+100A.
Note 3:Current into a pin designed as +,current out of a pin designed -;
Note 4:Voltage referred to pin 22,Tamb=25
C.
TEMPERATURE CHARACTERISTICS
(-20 TO +60
C )
PARAMETER PIN
TYP
CHANGE
UNIT
V+ Supply Current ( V+ 11V,Pin 18 = 0.7V )
16
-0.2
%/
C
V+ Supply Current(V+ 11V,Pin 18 = 1.6V )
16
-0.4
%/
C
VCC Voltage( V+ = 7.5V )
20
+0.1
%/
C
Attenuator Gain ( Max and Min Setting )
+-0.003
dB/
C
Delta RXO,TXO Voltage
4,26
+-0.24
%/
C
Speaker AMP Gain
15,19
+-0.001
dB/
C
Microphone AMP Gain
9,10
+-0.4
dB/
C
Microphone Amp Input Resistance
9
+0.4
%/
C
Tx-Rx Switching Threshold (20
A)
5,7 +-0.2
nA/
C
DESIGN GUIDELINES
(REF TO FIG. 1)
ATTENUATORS
The transmit and receive attenutors are complementary in function, i.e., when one is at maximum gain the other
is at maximum attenuator, and vice versa. They are never both on or both off. Their main purpose is to control the
transmit and receive paths to provide the half-duplx operation required of a speaker-phone. The attenuators are
controlled solely by the voltage at the ACF pin(pin 25).The ACF voltage is provided by the attenuator control block,
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