TECHNICAL DATA

TELEPHONE SPEECH NETWORK

ILA1062/1062A

WITH DIALER INT`ERFACE

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 k

) for

dynamic, magnetic or piezo-electric microphones
- Asymmetrical high-impedance input (32 k

) 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

PIN CONNECTION

BT1062A

GAS1

GAS2

GAR

MIC-

MIC+

STAB

SLPE

AGC

REG

MUTE

DTMF

ILA1062

ILA1062A

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.

QUICK REFERENCE DATA

Characteristic

Symbol

Test Condition

Min

Typ

Max

Unit

Line Voltage

line

= 15mA

3.55

4.0

4.25

Operating Line Current

line

2.0

Normal Operation

140

with Reduced Performance

Internal Supply Current

= 2.8V

0.9

1.35

Supply Voltage for Peripherals

line

= 15mA

= 1.2mA

= 0mA

2.2
2.2

2.7
3.4

Voltage Gain

microphone amplifier

receiving amplifier

Line loss compensation

Gain Control

5.8

Exchange Supply Voltage

exch

Exchange Feeding bridge Resistance

exch

0.4

ILA1062/1062A

FUNCTIONAL DESCRIPTION

Supplies V

, 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 V

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 V

and V

. The internal voltage regulator is decoupled by

a capacitor between REG and V

EE.

The DC current flowing into the set is determined by the exchange
supply voltage V

exch

, the feeding bridge resistance R

exch

and the DC

resistance of the telephone
line R

line

The circuit has internal current stabilizer operating at a level
determined by a 3.6 k

resistor connected between STAB and V

(see Fig.6). When the line current (I

line

) is more than 0.5mA greater

than the sum of the IC supply current (I

) and the current drawn by

the peripheral circuitry connected to V

) the excess current is

shunted to V

via LN.

The regulated voltage on the line terminal (V

) can be calculated as:

= V

ref

+ I

SLPE

x R9

= V

ref

+ {(I

line

- I

- 0.5 x 10

-3

A) - I

} x R9

ref

is an internally generated temperature compensated reference

voltage of 3.7V and R9 is an external resistor connected between
SLPE and V

EE.

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

Under normal conditions, when I

SLPE

>>I

+ 0.5mA + I

, the static

behaviour of the circuit is that of a 3.7V regulator diode with an
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.

At line currents below 9mA the internal reference voltage is
automatically adjusted to a lower value (typically 1.6V at 1mA). This
means that more sets can be operated in parallel with DC line voltage
(excluding the polarity guard) down to an absolute minimum voltage
of 1.6V. At line currents below 9mA the circuit has limited sending
and receiving levels. The internal reference voltage can be adjusted
by means of an external resistor (R

). 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 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 (ILA1062A)

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.

ILA1062/1062A

Automatic gain control input AGC

bal

line

(2)

Automatic line loss compensation is achieved by connecting a
resistor (R6) between AGC and V

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

If fixed values are chosen for R1, R2, R3 and R9, then condition (1)
will always be fulfilled when

0.5mm diameter twisted-pair copper cable with a DC resistance of
176

?/km and average attenuation of

To obtain optimum sidetone suppression, condition (2) has to be
fulfilled which results in:

bal

R 8

R 1

x Z

line

= k x Z

line

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

Where k is scale factor; k =

R 8

R 1

line-loss compensation is required the AGC pin may be left open-
circuit. The amplifiers, in this condition, will give their maximum
specified gain.

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 Z

bal

Sidetone suppression

bal

//R8

|<<R8 fulfilling condition (a) and thus

The anti-sidetone network, R1//Z

line

, R2, R3, R8, R9 and Z

bal

suppresses the transmitted signal in the earpiece. Maximum
compensation is obtained when the following conditions are fulfilled:

ensuring correct
anti-sidetone bridge operation
-

bal

+ R8

|>>R9 to avoid influencing the transmit gain.

In practise Z

line

varies considerably with the line type and length. The

value chosen for Z

bal

should therefore be for an average line thus

giving optimum setting for short or long lines.

R9 x R2 = R1 x

R 3

(1)

R 8

bal

ABSOLUTE MAXIMUM RATING

Characteristic

Symbol

Test Condition

Min

Typ

Max

Unit

Positive Continuous Line Voltage

Repetitive Line Voltage During Switch-on
or Line Interruption

LN(R)

13.2

Repetitive Peak Line Voltage for a 1ms
Pulse per 5s

LN(RM)

R9 = 20

; R10 = 13;

see Fig.6

Line Current

line

R9 = 20

; note 1

140

Input Voltage on all other Pins

-0.7

+0.7

Total Power

Standard DIP

tot

R9 = 20

; note 2

0.58

Dissipation

DIP with heatsink

0.67

Operating Ambient Temperature

-25

+75

Storage Temperature

stg

-40

+125

Junction Temperature

+125

Notes
1. Mostly dependent on the maximum required T

and on the voltage between LN and SLPE.

2. Calculated for the maximum ambient temperature specified and a maximum junction temperature of 125

(Thermal Resistance R

= 85

C/W for standard DIP and R

= 75

C/W for special DIP with heatsink).

(1)

= 45

C; P

tot

= 1.07 W

(2) T

= 55

C; P

tot

= 0.93 W

(3) T

= 65

C; P

tot

= 0.80 W

(4) T

= 75

C; P

tot

= 0.67 W

110

130

150

V - V

(V)

SLPE

I (mA)

(1)

(2)

(3)

(4)

110

130

150

V - V

(V)

SLPE

I (mA)

(1)

(2)

(3)

(4)

(1)

= 45

C; P

tot

= 0.94 W

(2) T

= 55

C; P

tot

= 0.82 W

(3) T

= 65

C; P

tot

= 0.71 W

(4) T

= 75

C; P

tot

= 0.58 W

Fig.3a Safe operating area Fig.3b Safe operating area
(Standard DIP) (DIP with HS)

ILA1062/1062A

ELECTRICAL CHARACTERISTICS

line

= 11mA to mA; V

= 0V; f = 800Hz; T

= 25

C; unless otherwise specified.

Characteristic

Symbol

Test Condition

Min

Typ

Max

Unit

Voltage Drop over Circuit between LN and V

MIC inputs open-circuit

line

= 1mA

line

= 4mA

line

= 15mA

line

= 100mA

line

= 140mA

3.55

4.9

1.6
1.9
4.0
5.7

4.25

6.5
7.5

Variation with Temperature

line

= 15mA

-0.3

mV/

Voltage Drop over Circuit Between LN and V

with External Resistor R

line

= 15mA

(LN to REG) = 68k

(REG to SLPE) = 39k

3.5
4.5

Supply Current

= 2.8V

0.9

1.35

Supply Voltage available for Peripheral Circuitry

line

= 15mA;

= 1.2mA

= 0mA

2.2

2.7
3.4

Microphone inputs MIC- and MIC+ (pins 6 and 7)

Input Impedance
Differential

between MIC- and MIC+

Single-ended

MIC- or MIC+ to V

Common mode rejection ratio

CMRR

Voltage Gain MIC+ or MIC- to LN

line

= 15mA; R7 = 68k

50.5 52.0

53.5 dB

Gain Variation with Frequency referenced to
800Hz

f = 300 and 3400 Hz

0.2

Gain Variation with Temperature referenced to
25

without R6; I

line

= 50mA;

= -25 and +75

0.2

DTMF Input (Pin 11)

Input Impedance

20.7

Voltage Gain from DTMF to LN

line

= 15mA; R7 = 68k

243.0 25.5 27.0 dB

Gain Variation with Frequency referenced to
800Hz

f = 300 and 3400 Hz

0.2

Gain Variation with Temperature referenced to
25

line

= 50mA;

= -25 and +75

0.2

Gain adjustment inputs GAS1 and GAS2 (Pins2 and 3)

Transmitting Amplifier Gain variation by
adjustment of R7 between GAS1 and GAS2

-8

Sending amplifier output LN (Pin1)

Output Voltage (RMS value)

LN(rms)

THD = 10 %

line

= 4mA

line

= 15mA

1.7

0.8
2.3

V
V

Receiving amplifier input IR (Pin 10)

Input Impedance

line

= 15mA; R

= 300

;

(from pin 9 to

Receiving amplifier output QR (Pin 4)

Output Impedance

Voltage Gain from IR to QR

line

= 15mA; R

= 300

;

(from pin 9 to pin 4)

29.5 31

32.5 dB

Gain Variation with Frequency referenced to
800Hz

f = 300 and 3400 Hz

0.2

Gain Variation with Temperature referenced to
25

without R6; I

line

= 50mA;

= -25 and +75

0.2

Электронный компонент: ILA1062