TECHNICAL DATA
Universal Speech Circuit
with Dialler Interface
ORDERING INFORMATION
IL3726AN
T
A
= -40
to 70 C
The IL3726AN is a low voltage speech network which includes Mic amp. transmit
amp, receive amp. and stabilized DC-supply It handles the voice signal performing
the 2/4 wire interface and changing the gain on both sending and receiving
amplifiers to compensate for line attenuation by sensing the line length through the
line current.
Application dependent parameters such as amplitude of each amp, sidetone level,
line balance and frequency response are controlled by external components. Each
gain can be controlled by external component exchange.
IL3726AN
Uses a minimum of external components (7 Capacitors & 11 Resistors)
Low Voltage Operating
Symmetrical inputs for microphones, provided good balance to ground
DTMF signal input with confidence tone
Mute input for DTMF dialling
Line loss compensation (line current dependent) for microphone and earpiece amplifiers
Gain control curve adaptable to exchange supply
DC line voltage adjustment facility
BLOCK DIAGRAM
1
12
13
10
8
17
18
14
15
16
11
2
6
5
4
3
9
7
DC
1
IL3726A
PIN DESCRIPTION PIN CONFIGURATION
Pin No
Designation
Description
1
V +
Positive power line and transmit amplifier
output.
2
TXO
Transmit amplifier output. The resistor which is
connected this pin to V - sets the DC
resistance of circuit. The value of resistor is
suitable for 47 to 100.
3
TXI
Transmit amplifier input. Input impedance is
17k
20%.
4
V
DD
Positive power supply pin for internal circuitry.
This pin will be connected to a decoupling
capacitor 47 F
- 100 F.
5
MUTE
Mute input : Active low .
6
GR
Gain regulation control input
7
DCS
Sense input to the DC supply
8
DCO
Output from the DC supply
9
DCC
Control output from the DC supply
10
DTMF
Dual-tone Multi-Frequency Input
11
MIC0
Microphone a ifier output.
12, 13 MIC1, MIC2
Microphone amplifier inputs. Input impedance
is 1.7k
20%
14
V
Negative power line
15
RXI
Receive amplifier input. . Input impedance is
~38k
20%
16
DR
Receive amplifier driving capability control
input
17, 18 RXO1, RXO2
Receive amplifier output. Output impedance is
3 (Typ).
3
1
2
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
1
7
V+
TXO
TXI
V
DD
DCS
GR
Mute
DTMF
DCC
DCO
RXI
V-
MICO
MIC1
MIC2
DR
RXO2
RXO1
MAXIMUM RATINGS
Symbol Parameter Min
Max
Unit
V
LN
Positive line voltage, t
p
= 2s
0
18
V
I
line
Line current continious
0
130
mA
Tstg Storage
temperature
-55
+125
C
T
J
Operating temperature range
-40
+70
C
No input should be set on higher level than pin4
ELECTRICAL CHARACTERISTICS
(T
amb
= 25 C)
2
IL3726A
Characteristic
Symbol Test
Conditions
Min.
Typ. Max.
Unit
Line Voltage
VLN
IL = 15mA
IL = 100mA
3.3
11.0
3.7
13.0
4.1
15.0
V
TX Gain
GV (TX)
RL = 0
RL = 400
RL = 900 - 2.2 k
41
43.5
46
43
45.5
48
45
47.5
50
dB
TX Range of Regulation
GTX
RL = 0 - 900 , 1 kHz 3
5
7
dB
TX Frequency Response
GTX(RE
S)
200Hz to 3400 Hz
1
dB
TX Dynamic Output
Voltage
VO(TX)
200Hz to 3400 Hz,
IL = 20 - 100 mA
1.5
Vp-p
TX Max Output Voltage
VOTX(M
AX)
200Hz to 3.4 kHz,
IL = 0 - 100mA
3
Vp-p
TX Input Impedance
ZI (TX)
1 kHz
13.5
17
20.5
k
Mute Input Voltage
VI
(MUTE)
0.3
V
RX Gain
GV (RX)
RL = 0
RL = 400
RL = 900
- 2.2 k
-18.5
-16
-13.5
-16.5
-14
-11.5
-14.5
-12
-9.5
dB
RX Range of Regulation
GRX
RL =0 - 900
, 1 kHz
3
5
7
dB
RX Frequency Response
GRX(RE
S)
200 Hz - 3400 Hz
-1
1
dB
RX Dynamic Output
Voltage
VO(RX)
200 Hz - 3400 Hz
IL = 20 - 100 mA
0.5
Vp-p
RX Max Output Voltage
VORX(M
AX)
200 Hz - 3400 Hz
IL = 0 - 100mA
0.9
Vp-p
RX output impedance
ZO(RX)
1 kHz
3
Microphone input impedance
ZI (Mic)
1 kHz
1.7
k
Transmitter output noise
-75
dB
Receiver output noise
- 85
dB
DC supply voltage
IL = 21 - 100 mA
IDC = 0 mA
IDC = 2 mA
2.1
1.95
2.35
2.2
2.6
2.45
V
V
DC supply current
2
mA
DTMF transmitting gain
24.5
26.5
28.5
dB
DTMF input impedance
20
25
30
k
3
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