ILA1062/ILA1062A
TELEPHONE SPEECH NETWORK WITH DIALER INTERFACE
DESCRIPTION
The ILA1062 and ILA1062A are integrated circuits that perform all speech and line interface
functions required in fully
electronic telephone sets. They perform electronic switching between dialing and speech. The ICs
operates at line voltage down
to 1.6 V DC (with reduced performance) to facilitate the use of more telephone sets connected in
parallel.
All statements and values refer to all versions unless otherwise specified. The ILA1062(ILA1062A)
is packaged in a standard
16-pin plastic DIP and special plastic DIP with internal heatsink is also available.
PIN CONNECTION
FEATURES
Low DC line voltage; operates down to 1.6V
(excluding
polarity guard)
· Voltage regulator with adjustable static resistance
· Provides a supply for external circuits
· Symmetrical high-impedance inputs (64 kΩ) for
dynamic, magnetic or piezo-electric microphones
· Asymmetrical high-impedance input (32 kΩ) for
electret
microphones
· DTMF signal input with confidence tone
· Mute input for pulse or DTMF dialing
- ILA1062: active HIGH (MUTE)
- ILA1062A: active LOW (MUTE)
· Receiving amplifier for dynamic, magnetic or
piezo-electric earpieces
· Large gain setting range on microphone and
earpiece
amplifiers
· Line loss compensation (line current dependent) for
microphone and earpiece amplifiers
· Gain control curve adaptable to exchange supply
· DC line voltage adjustment facility
·
1
1
16
SLPE
GAS1 2
15
AGC
GAS2
3
14
REG
OR
4
13
VCC
GAR
5
12
MUTE
MIC-
6
11
DTMF
MIC+
7
10
IR
STAB
8
9
VEE
LN
ILA1062A
BT1062A
ILA1062/ILA1062A
QUICK REFERENCE DATA
Characteristic
Symbol
Test Condition
Min
Typ
Max
Unit
Line Voltage
VLN
Iline = 15mA
3.55
4.0
4.25
V
Operating Line Current
I line
2.0
Vdc
Normal Operation
11
140
mA
with Reduced Performance
1
11
mA
1.35
mA
V
Internal Supply Current
Supply Voltage for Peripherals
I CC
VCC
Voltage Gain
VCC = 2.8V
Iline= 15mA
Ip= 1.2mA
Ip= 0mA
0.9
2.2
2.2
2.7
3.4
GV
microphone amplifier
44
52
dB
receiving amplifier
20
31
dB
Line loss compensation
Gain Control
DGV
5.8
Exchange Supply Voltage
Vexch
36
60
V
Exchange Feeding bridge
Resistance
Rexch
0.4
1
kW
BLOCK DIAGRAM
VCC
LN
13
IR
1
10
5
-
ILA1062A
4
GAR
QR
+
MIC+
MIC-
DTMF
(1)
MUTE
7
+
2
6
-
-
+
11
+
dB
3
-
12
SUPPLY AND
REFERENCE
CONTROL
CURRENT
LOW VOLTAGE
CIRCUIT
CURRENT
REFERENCE
9
VEE
14
REG
GAS1
15
8
AGC
STAB
16
SLPE
(1) Pin 12 is active HIGH (MUTE) for ILA1062.
Fig.1 Block diagram for ILA1062A
2
GAS2
dB
ILA1062/ILA1062A
FUNCTIONAL DESCRIPTION
Supplies VCC, LN, SLPE, REG and STAB
Power for the IC and its peripheral circuits is usually obtained from the telephone line. The supply voltage is
delivered from the line via a dropping resistor and regulated by the IC. The supply voltage VCC may also be
used to supply external circuits e.g. dialing and control circuits.
Decoupling of the supply voltage is performed by a capacitor between VCC and VEE . The internal voltage
regulator is decoupled by a capacitor between REG and VEE.
The DC current flowing into the set is determined by the exchange supply voltage Vexch , the feeding bridge
resistance Rexch and the DC resistance of the telephone
line Rline .
The circuit has internal current stabilizer operating at a level determined by a 3.6 k? resistor connected
between STAB and VEE (see Fig.6). When the line current (Iline) is more than 0.5mA greater than the sum of
the IC supply current (ICC) and the current drawn by the peripheral circuitry connected to VCC (Ip) the excess
current is shunted to VEE via LN.
The regulated voltage on the line terminal (VLN) can be calculated as:
VLN = Vref + ISLPE x R9
VLN = Vref + {(Iline - ICC - 0.5 x 10-3A) - Ip} x R9
Vref is an internally generated temperature compensated reference voltage of 3.7V and R9 is an external
resistor connected between SLPE and VEE.
In normal use the value of R9 would be 20?.
Changing the value of R9 will also affect microphone gain, DTMF gain, gain control characteristics, sidetone
level, maximum output swing on LN and the DC characteristics (especially at the lower voltages).
Fig.2 Equivalent impedance circuit
LN
Under normal conditions, when ISLPE >>ICC + 0.5mA + Ip, the static
behaviour of the circuit is that of a 3.7V regulator diode with an
Rp
R1
Leq
internal resistance equal to that of R9. In the audio frequency
range the dynamic impedance is largely determined by R1. Fig.2
show the equivalent impedance of the circuit.
Vref
At line currents below 9mA the internal reference voltage is
REG
VCC
automatically adjusted to a lower value (typically 1.6V at 1mA).
R9
This means that more sets can be operated in parallel with DC
20Ω
C1
C3
line voltage (excluding the polarity guard) down to an absolute
100µF
4.7µF
minimum voltage of 1.6V. At line currents below 9mA the circuit
VEE
has limited sending and receiving levels. The internal reference
Leq = C3 x R9 x Rp
voltage can be adjusted by means of an external resistor (RVA).
Rp = 16.2 kΩ
This resistor when connected between LN and REG will decrease
the internal reference voltage and when connected between REG
and SLPE will increase the internal reference voltage.
Microphone inputs MIC+ and MIC- and gain pins GAS1 and GAS2
The circuit has symmetrical microphone inputs. Its input impedance is 64 k? (2 x 32k?) and its voltage gain is
typically 52 dB (when R7 = 68k?; see Fig.6).
Dynamic, magnetic, piezo-electric or electret (with built-in FET source followers) can be used.
The gain of the microphone amplifier can be adjusted between 44 dB and 52 dB to suit the sensitivity of the
transducer in use. The gain is proportional to the value of R7 which is connected between GAS1 and GAS2.
Stability is ensured by two external capacitors, C6 connected between GAS1 and SLPE and C8 connected
between GAS1 and VEE. The value of C6 is 100pF but this may be increased to obtain a first-order low-pass
3
ILA1062/ILA1062A
filter. The value of C8 is 10 times the value of C6. The cut-off frequency corresponds to the time constant R7
x C6.
Input MUTE (ILA1062)
When MUTE is LOW or open-circuit, the DTMF input is enable and the microphone and receiving amplifier
inputs are inhibited. The reverse is true when MUTE is HIGH.
MUTE switching causes only negligible clicking on the line and earpiece output. If the number of parallel sets
in use causes a drop in line current to below 6 mA the DTMF amplifier becomes active independent to the
DC level applied to the MUTE input.
Dual-tone multi-frequency input DTMF
When the DTMF input is enable dialing tones may be sent on to the line. The voltage gain from DTMF to LN
is typically 25.5 dB (when R7=68k?) and varies with R7 in the same way as the microphone gain. The
signalling tones can be heard in the earpiece at a low level (confidence tone).
Receiving amplifier IR, QR and GAR
The receiving amplifier has one input (IR) and a non-inverting output (QR). The IR to QR gain is typically
31dB (when R4 = 100k?). It can be adjusted between 20 and 31dB to match the sensitivity of the transducer
in use. The gain is set with the value of R4 which is connected between GAR and QR. The overall receive
gain, between LN and QR, is calculated by subtracting the anti-sidetone network attenuation (32dB) from the
amplifier gain. Two external capacitors, C4 and C7, ensure stability. C4 is normally 100pF and C7 is 10
times the value of C4. The value of C4 may be increased to obtain a first-order low-pass filter. The cut-off
frequency will depend on the time constant R4 x C4.
The output voltage of the receiving amplifier is specified for continuous-wave drive. The maximum output
voltage will be higher under speech conditions where the peak to RMS ratio is higher.
Automatic gain control input AGC
Automatic line loss compensation is achieved by connecting a resistor (R6) between AGC and VEE.
The automatic gain control varies the gain of the microphone amplifier and the receiving amplifier in
accordance with the DC line current. The control range is 5.8 dB which corresponds to a line length of 5 km
for a
0.5mm diameter twisted-pair copper cable with a DC resistance of 176 ?/km and average attenuation of
1.2dB/km. Resistor R6 should be chosen in accordance with the exchange supply voltage and its feeding
bridge resistance. The ratio of start and stop currents of the AGC curve is independent of the value of R6. If
no automatic
line-loss compensation is required the AGC pin may be left open-circuit. The amplifiers, in this condition, will
give their maximum specified gain.
Sidetone suppression
The anti-sidetone network, R1//Zline, R2, R3, R8, R9 and Zbal suppresses the transmitted signal in the
earpiece. Maximum compensation is obtained when the following conditions are fulfilled:
R9 x R2 = R1 x
Z bal
Z bal + R 8
=
R3+
Z line
Z line + R 1
R 8 x Z bal
R 8 + Zbal
(1)
(2)
If fixed values are chosen for R1, R2, R3 and R9, then condition (1) will always be fulfilled when
To obtain optimum sidetone suppression, condition (2) has to be fulfilled which results in:
4
ILA1062/ILA1062A
Zbal =
R8
R1
x Zline = k x Zline
Where k is scale factor; k =
R8
R1
The scale factor k, dependent on the value of R8, is chosen to meet the following criteria:
· compatibility with a standard capacitor from the E6 or
E12 range for Zbal
· |Zbal//R8|<<R8 fulfilling condition (a) and thus
ensuring correct
anti-sidetone bridge operation
· |Zbal + R8|>>R9 to avoid influencing the transmit gain.
In practise Zline varies considerably with the line type and length. The value chosen for Zbal should therefore
be for an average line thus giving optimum setting for short or long lines.
ABSOLUTE MAXIMUM RATING
Characteristic
Symbol
Test Condition
Min
Typ
Max
Unit
Positive Continuous Line
VLN
12
V
Voltage
Repetitive Line Voltage During
VLN(R)
13.2
V
Switch-on or Line Interruption
Repetitive Peak Line Voltage
VLN(RM)
R9 = 20W; R10 = 13W;
28
V
for a 1ms Pulse per 5s
see Fig.6
Line Current
Iline
R9 = 20W; note 1
140
mA
VCC+0.7
Input Voltage on all other Pins
VI
-0.7
V
Total
Standard DIP
Ptot
R9 = 20W; note 2
0.58
W
Power
Dissipation DIP with heatsink
0.67
o
Operating Ambient
TA
-25
+75
C
Temperature
o
Storage Temperature
Tstg
-40
+125
C
o
Junction Temperature
Tj
+125
C
Notes
1. Mostly dependent on the maximum required TA and on the voltage between LN and SLPE.
2. Calculated for the maximum ambient temperature specified and a maximum junction temperature of
125oC.
(Thermal Resistance RJA = 85oC/W for standard DIP and RJA = 75oC/W for special DIP with heatsink).
(1) TA=45oC; Ptot=0.94W
(2) TA=55oC; Ptot=0.82W
(3) TA=65oC; Ptot=0.71W
(4) TA=75oC; Ptot=0.58W
(1) TA=45oC; Ptot=1.07W
(2) TA = 55oC; Ptot=0.93W
(3) TA=65oC; Ptot=0.80 W
(4) TA=75oC; Ptot=0.67 W
150
ILN (mA)
130
110
150
ILN (mA)
130
110
(1)
(1)
90
(2)
90
(2)
(3)
70
(3)
70
(4)
(4)
50
50
30
30
2
4
6
8
10
VLN - VSLPE (V)
12
Fig.3a Safe operating area(Standard DIP)
5
2
4
6
8
10
VLN - VSLPE (V)
12
Fig.3b Safe operating area (DIP with HS)
ILA1062/ILA1062A
CHARACTERISTICS
o
Iline = 11mA to mA; VEE = 0V; f = 800Hz; TA = 25 C; unless otherwise specified.
Characteristic
Voltage Drop over Circuit between LN and
VEE
Variation with Temperature
Voltage Drop over Circuit Between LN and
VEE with External Resistor RVA
Supply Current
Supply Voltage available for Peripheral
Circuitry
Symbol
Test Condition
VLN
MIC inputs open-circuit
Iline = 1mA
Iline = 4mA
Iline = 15mA
Iline = 100mA
Iline = 140mA
Iline = 15mA
Iline = 15mA
RVA(LN to REG) = 68kW
RVA(REG to SLPE) = 39kW
VCC = 2.8V
Iline = 15mA;
Ip = 1.2mA
Ip = 0mA
|VLN/|T
VLN
ICC
VCC
Min
Typ
3.55
4.9
1.6
1.9
4.0
5.7
Max
V
4.25
6.5
7.5
-0.3
3.5
4.5
0.9
2.2
Unit
o
mV/ C
V
1.35
mA
V
2.7
3.4
Microphone inputs MIC- and MIC+ (pins 6 and 7)
Input Impedance
Differential
Single-ended
Common mode rejection ratio
Voltage Gain MIC+ or MIC- to LN
Gain Variation with Frequency referenced
to 800Hz
Gain Variation with Temperature referenced
o
to 25 C
|Zi |
CMRR
Gv
DGvf
DGvT
kW
between MIC- and MIC+
MIC- or MIC+ to VEE
Iline = 15mA; R7 = 68kW
f = 300 and 3400 Hz
50.5
64
32
82
52.0
± 0.2
53.5
± 0.2
without R6; Iline = 50mA;
o
TA = -25 and +75 C
kW
dB
dB
dB
dB
DTMF Input (Pin 11)
Input Impedance
Voltage Gain from DTMF to LN
Gain Variation with Frequency referenced
to 800Hz
Gain Variation with Temperature referenced
o
to 25 C
|Zi |
Gv
DGvf
DGvT
Iline = 15mA; R7 = 68kW
f = 300 and 3400 Hz
243.0
20.7
25.5
± 0.2
27.0
± 0.2
Iline = 50mA;
o
TA = -25 and +75 C
kW
dB
dB
dB
Gain adjustment inputs GAS1 and GAS2 (Pins2 and 3)
Transmitting Amplifier Gain variation by
adjustment of R7 between GAS1 and GAS2
DGv
-8
0
dB
Sending amplifier output LN (Pin1)
Output Voltage (RMS value)
Noise Output Voltage (RMS value)
VLN(rms)
Vno(rms)
THD = 10 %
Iline = 4mA
Iline = 15mA
Iline = 15mA; R7 = 68kW; 200W
between MIC- and MIC+;
V
1.7
0.8
2.3
-69
dBmp
21
kW
Receiving amplifier input IR (Pin 10)
Input Impedance
|Zi |
Receiving amplifier output QR (Pin 4)
Output Impedance
Voltage Gain from IR to QR
|Zo |
Gv
Gain Variation with Frequency referenced
to 800Hz
Gain Variation with Temperature referenced
o
to 25 C
DGvf
Output Voltage (RMS value)
Iline = 15mA; RL = 300W;
(from pin 9 to pin 4)
f = 300 and 3400 Hz
DGvT
without R6; Iline = 50mA;
o
TA = -25 and +75 C
Vo(rms)
THD = 2%; sine wave drive;
R4 = 100kW; Iline = 15mA;
Ip = 0mA
RL = 150W
RL = 450W
6
29.5
0.22
0.3
4
31
32.5
W
dB
± 0.2
dB
± 0.2
dB
0.33
0.48
V
V
ILA1062/ILA1062A
Characteristic
Symbol
Output Voltage (RMS value)
Vo(rms)
Noise Output Voltage (RMS value)
Vno(rms)
Test Condition
Min
THD = 10%; R4 = 100kW;
RL = 150W; Iline = 4mA
Iline = 15mA; R4 = 100kW;
IR open-circuit
RL = 300W
Typ
Max
Unit
15
mV
50
mV
Gain adjustment input GAR (Pin 5)
Receiving Amplifier Gain Variation by
adjustment of R4 between GAR and QR
DGv
-11
0
dB
HIGH Level Input Voltage
VIH
1.5
VCC
V
LOW Level Input Voltage
VIL
0.3
V
15
mA
Mute input (Pin 12)
Input Current
IMUTE
8
Reduction of Gain
dB
DGv
MIC+ or MIC- to LN
TEA1062
TEA1062A
Voltage Gain from DTMF to QR
TEA1062
TEA1062A
70
70
MUTE = HIGH
MUTE = LOW
R4 = 100kW; RL = 300W
MUTE = HIGH
MUTE = LOW
Gv
dB
-17
-17
Automatic Gain Control Input AGC (Pin 15)
Controlling the Gain from IR to QR and the
Gain from MIC+, MIC- to LN
Gain Control Range
DGv
Highest Line Current for Maximum Gain
IlineH
5.8
23
dB
mA
IlineL
61
mA
Lowest Line Current for Minimum Gain
R6 = 110kW
(between AGC and VEE)
Iline = 70mA
2.4
(1)
Ip
(mA)
(2)
1.6
0.8
0
0
1
2
4
3
VCC(V)
Fig.4 Typical current Ip available from VCC for peripheral circuitry.
The supply possibilities can be increased by setting the voltage drop over the circuit VLN to a higher value be
resistor RVA connected between REG and SLPE.
VCC > 2.2V; Iline = 15mA at VLN = 4V; R1 = 620W; R9 = 20W
(1) Ip = 2.1mA. Curve (1) is valid when the receiving or when MUTE = HIGH(ILA1062), MUTE =
LOW(ILA1062A).
(2) Ip = 1.7mA. Curve (2) is valid when MUTE = LOW(ILA1062), MUTE = HIGH(ILA1062A) and the receiving
amplifier is driven; Vo(rms) = 150mV, RL = 150W.
7
R6 =
0
8
ILA1062/ILA1062A
∆GV
(dB)
-2
-4
-6
20
0
40
80
60
100
120
140
Iline (mA)
R9 = 20 Ω
Fig. 5 Variation of gain as a function of the line current with R6 as a parameter
TABLE 1
Values of resistor R6 for optimum line-loss compensation at various values of exchange supply voltage
(Vexch) and exchange bridge resistance (Rexch ); R9 = 20W.
Vexch (V)
400 Rexch (W)
600 Rexch (W)
800 Rexch (W)
1000 Rexch (W)
R6 (kW)
36
100
78.7
-
-
48
140
110
93.1
82
60
-
-
120
102
PINNING
Pin
Symbol
Description
1
LN
2
GAS1
Gain Adjustment; Transmitting Amplifier
3
GAS2
Gain Adjustment; Transmitting Amplifier
4
QR
5
GAR
Gain Adjustment; Receiving Amplifier
6
MIC-
Inverting Microphone Input
7
MIC+
Non-inverting Microphone Input
8
STAB
Current Stabilizer
9
VEE
Negative Line Terminal
10
IR
Receiving Amplifier Input
11
DTMF
Dual-tone Multi-Frequency Input
12
MUTE
Mute Input (see note 1)
13
VCC
Positive Supply Decoupling
14
REG
Voltage Regulator Decoupling
15
AGC
Automatic Gain Control Input
16
SLPE
Slope (DC resistance) Adjustment
Positive Line Terminal
Non-inverting Output; Receiving Amplifier
Note 1. Pin 12 is active HIGH (MUTE) for ILA1062
8
9
Zbal
R3
3.92kΩ
C2
R2
130kΩ
R8
390Ω
C7
1 nF
100pF
(1) Pin 12 is
R9
20Ω
6
7
5
4
10
BT1062.
RVA (REG to SLPE).
protection arrangement is required for pulse dialling or register recall.
active HIGH (MUTE) for
C6
100 pF
16
MICSLPE
MIC+
GAR
QR
IR
LN
1
C8
1 nF
2
GAS1
R7
RVA(R16-14)
3
GAS2
+
C3
4.7
µF
14
REG
ILA1062A
620Ω
R1
current into, and the voltage across, the circuit during line transients.
R4
C4
100 nF
C5
The DC line voltage can be set to a higher value by the resistor
A different
The diode bridge, the Zener and R10 limit the
telephone
line
BZW14
(2x)
BAS11
(2x)
R10
13Ω
BZX79
C12
R6
15
AGC
13
R5
3.6
kΩ
8
STAB
VCC
(1)
VEE
9
MUTE
DTMF
12
11
+
C1
100
µF
-
from dial
and
control circuits
+
ILA1062/ILA1062A
APPLICATION INFORMATION
Fig. 6 Typical application of ILA1062A, with piezo-electric earpiece and DTMF dialling