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Электронный компонент: U4050B

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U4050B
Rev. A2, 05-Mar-98
1 (18)
Speech Circuit with Line-Powered Loudspeaker Amplifier
Description
The electronic speech circuit U4050B is a linear
integrated circuit for use in telephone sets. It replaces the
hybrid transformer, sidetone equivalent and ear
protection rectifiers.
The circuit is line powered and contains all components
necessary for amplification of signals and adaptation to
the line. An integrated loudspeaker amplifier allows
loudhearing operation.
Features
D Integrated amplifier for loudhearing operation
D Anticlipping for loudspeaker amplifier
D Supply voltages for all functional blocks of a
subscriber set
D Adjustable DC characteristics
D Adjustable sending and receiving amplification
D Automatic line loss compensation
D Symmetrical output of earpiece amplifier
D Built-in ear protection
D Symmetrical input of microphone amplifier
D Adjustable sidetone suppression independent
of sending and receiving amplification
D DTMF and MUTE inputs
D Anticlipping in transmit direction
D Squelch
D Integrated transistor for short circuiting the line
voltage
D Power down
D Operation possible at line currents above 10 mA
Benefits
D Independent adjustment of transmit gain, receive gain
and sidetone suppression
D Low number of external components
Block Diagram
Power supply
SA
SAI
TXA
RECO2
RECO1
5
16
15
14
13
12
11
8
7
6
3
GSA
SAO
CLISA
AGA
CK
VL
RDC
VC
VD
VM
SWAMP
IREF
GND
PD
MUTE
CLIM
+
+
LIMITER
GS
MICO
TIN
ST
GR
MIC1
DTMF
MIC2
LEVSQ
CSQ
2
9
10
4
1
17
18
19
20
21
22
23
24
25
26
27
28
MUTE
SQUELCH
AGA
NSA
LIMSA
+
REC. ATT.
U4050B
Figure 1. Block diagram
Ordering Information
Extended Type Number
Package
Remarks
U4050B-AFL
SO28
U4050B-AFLG3
SO28
Taped and reeled
U4050B
Rev. A2, 05-Mar-98
2 (18)
Block Diagram / Application Circuit
With a squelch function, acoustical feedback during
loudhearing can be reduced significantly. The generated
supply voltage is suitable for a wide range of peripheral
circuits.
2.2
CGR
3.3k
RNW3
CC
68n
CL
1k
RIMP
CIMP
27k
RNW1
100n
CNW1
RGSA
100k
470n
CLIM
47k
RREF
39
RSW
AMP
22
CM
1000
CD
>60k
RC
150n
CK
7.5k
RAGA
4.7
CLISA
47
CSAO
390
RR2
15k
RR1
1k
RNW2
22n
CNW2
12k
RS1
300
RS2
100n
CDTMF
100k
RSQ
1
CSQ
20k
RDTMF
100n
CTIN
RDC
10
13V
network
Sidetone
VM
Power supply
SA
direkt an Pin 22
LINE
PD
MUTE
+
+
+
+
+
+
DTMF
RL
SAI
TXA
RECO2
RECO1
5
16
15
14
13
12
11
8
7
6
3
GSA
SAO
CLISA
AGA
CK
VL
RDC
VC
VD
VM
SW
AMP
IREF
GND
PD
MUTE
CLIM
+
+
LIMITER
GS
MICO
TIN
ST
GR
MIC1
DTMF
MIC2
LEVSQ
CSQ
2
9
10
41
17
18
19
20
21
22
23
24
25
26
27
28
MUTE
SQUELCH
AGA
NSA
LIMSA
+
VM
REC. A
T
T
.
+
+
U4050B
93 7815 e
10
m
10
m
m
m
50
m
m
m
m
Figure 2.
Typical application diagram
U4050B
Rev. A2, 05-Mar-98
3 (18)
Pin Description
1
2
3
4
5
6
7
8
10
9
27
22
21
20
18
19
17
12
11
28
25
26
23
24
CK
MICO
DTMF
GS
MIC1
MIC2
ST
CLIM
LEVSQ
RECO1
GR
RECO2
VL
GND
SAO
VD
RDC
SWAMP
PD
VC
CLISA
GSA
AGA
IREF
16
15
14
13
14052
CSQ
VM
MUTE
TIN
Figure 3. Pinning S028
Pin
Symbol
Function
1
3
RECO2,
RECO1
Symmetrical outputs of receiving
amplifier
2
GR
A resistor connected from this pin to
V
M
(AC coupled) sets the receiving
amplification at the circuit
4
ST
Input of sidetone amplifier
5
CLIM
Time constant of anticlipping in trans-
mit patch
6
CK
Input of receiving path
7
MICO
Output of microphone preamplifier
8
DTMF
Input for DTMF signals (ac coupled).
In Mute condition a small portion of
the signal at this pin is monitored to
the receiver output.
9
GS
A resistor from this pin to V
M
sets the
amplification of microphone and
DTMF signals.
10
MIC1
Inverting input of microphone ampli-
fier
Pin
Symbol
Function
11
MIC2
Non-inverting input of microphone
amplifier
12
LEVSQ
Input for setting the switching level of
the squelch circuit
13
CSQ
Time constant of the squelch function
14
VM
Reference node for microphone, ear-
phone and loudspeaker amplifier.
Supply for electret microphone set to
V
D
/2.
15
TIN
Input of intermediate transmit stage
16
MUTE
Active high input to switch the circuit
into DTMF condition.
17
CLISA
Time constant of anticlipping of
speaker amplifier.
18
SWAMP
A resistor connected from this pin to
ground converts the excess line cur-
rent into heat in order to prevent the
IC from thermal destruction at high
line currents
19
RDC
A small resistor connected from this
pin to V
L
sets the slope of the charac-
teristic and also affects the line length
equalization characteristics and the
line current at which the loudspeaker
amplifier is switched on.
20
VD
Unregulated supply voltage for pe-
ripheral circuits (dialers, microproces-
sors, etc.). Output current capability
and output voltage increase with line
current.
21
SAO
Output of loudspeaker amplifier.
22
GND
Reference point for DC and AC out-
put signals
23
VL
Line voltage
24
VC
The internal equivalent inductance of
the circuit is proportional to the value
of the capacitor at this pin. A resistor
connected to ground may be used to
reduce the line voltage.
25
PD
Active high input for reducing the
current consumption of the circuit.
Simultaneously V
L
is shorted by an
internal switch.
26
GSA
Current input for setting the gain of
the speaker amplifier
27
AGA
Automatic gain adjustment with line
current. A resistor connected from this
pin to V
L
sets the starting point.
Maximum gain change is 6 dB.
28
IREF
Internal reference current generation
U4050B
Rev. A2, 05-Mar-98
4 (18)
Absolute Maximum Ratings
Parameters
Symbol
Value
Unit
Line current
I
L
140
mA
Line voltage
V
L
15
V
Junction temperature
T
j
150
C
Ambient temperature
T
amb
25 to +75
C
Storage temperature
T
stg
55 to +150
C
Total power dissipation (T
amb
= 60
C, SO28)
P
tot
750
mW
Thermal Resistance
Parameters
Symbol
Value
Unit
Junction ambient SO28
R
thJA
120
K/W
Electrical Characteristics
Test conditions unless otherwise specified: f = 1 kHz, 0 dBm = 775 V
rms
, I
M
= 0.3 mA, I
D
= 2 mA, RC = 130 k
,
T
amb
= 25
C, R
GSA
= 560 k
, Z
H
= Z
M
= 68 nF, Pin AGA open
Parameters
Test Conditions / Pins
Symbol
Min.
Typ.
Max.
Unit
DC characteristics
see figure 4
I
L
= 2 mA
V
L
1.9
V
DC oltage drop
I
L
= 15 mA
V
L
4.8
5.2
5.6
V
DC voltage drop
over circuit
I
L
= 19 mA
V
L
5.4
V
over circuit
I
L
= 30 mA
V
L
6.0
V
I
L
= 100 mA
V
L
9.5
V
Transmission amplifier
see figures 5 and 11
Adjustment
range of transmit gain
I
L
= 15 mA
G
S
40
48
56
dB
Transmitting
amplification
I
L
= 15 mA
G
S
47.75
48.25
48.75
dB
Frequency response
I
L
w 15 A, C
L
= 4.7 nF
f = 300 to 3400 Hz
DG
S
"0.5
dB
Gain change with current
Pin AGA open
I
L
= 15 to 100 mA
DG
S
"0.5
dB
Gain deviation
T
amb
= 10 to + 60
C
I
L
= 15 mA
DG
S
"0.5
dB
CMRR of microphone
amplifier
CMRR
60
80
dB
Input resistance of MIC
amplifier
R
i
45
60
80
k
Distortion at line
I
L
> 15 mA
V
L
= 775 mV2rms
d
s
2
%
Maximum output voltage
I
L
> 19 mA d < 5%
V
mic
= 10 m
V
1max
1.8
3
4.2
dBm
Noise at line
psophometrically weighted
I
L
> 15 mA
G
S
= 48 dB
n
o
80
72
dBmp
Anticlipping
attack time
V
mic
= 20 mV
C = 470 nF
0.5
ms
Release time
Each 3 dB overdrive
9
ms
U4050B
Rev. A2, 05-Mar-98
5 (18)
Unit
Max.
Typ.
Min.
Symbol
Test Conditions / Pins
Parameters
Gain at low operating
current
I
L
= 10 mA, I
D
= 1 mA
RC
= 68 k
V
mic
= 1 mV I
M
= 0 mA
G
S
47
50
dB
Distortion at low
operating current
I
L
= 10 mA, I
M
= 0 mA
I
D
= 1 mA, RC = 68 k
V
mic
= 10 mV
ds
6
%
Line loss compensation
I
L
= 100 mA
R
AGA
= 7.5 k
DG
SI
5
6
7
dB
Mute suppression
I
L
w 15 mA
V
mute
= 1.5 V
G
SM
60
dB
Receiving amplifier
see figures 6 and 8
Adjustment range of
receiving gain
I
L
w 15 mA
differential
G
R
8
+ 8
dB
Receiving amplification
I
L
= 15 mA
differential
G
R
1
0.5
0
dB
Amplification of DTMF
signal from DTMF IN
to RECO 1/2
I
F
w 15 mA
Mute active
G
RM
15
12
9
dB
Frequency response
I
L
> 15 mA, C
L
= 4.7 nF
f = 300 to 3400 Hz
DG
RF
"0.5
dB
Gain change with current
I
L
= 15 to 100 mA
DG
R
"0.5
dB
Gain deviation
T
amb
= 10 to + 60
C
I
L
= 15 mA
DG
R
"0.5
dB
Ear protection
differential
I
L
w 15 mA
V
gen
= 11 V
rms
V
ep
2.2
V
rms
Output resistance
Each output
against GND
R
o
10
Line loss compensation
I
L
= 100 mA
R
AGA
= 7.5 k
DG
RI
5.0
6.0
7.0
dB
Output voltage
Push pull
Single ended
I
L
= 15 mA, d
v 2%
Z
H
= 68 nF
Z
H
= 450
Z
H
= 150
0.775
0.6
0.3
V
rms
Receiving noise
psophometrically
weighted
Z
H
= 68 nF
G
R
= 0 dB
I
L
> 15 mA
n
i
83
78.5
dBmp
Gain at low operating
current
I
L
= 10 mA
I
D
= 1 mA
I
M
= 0 mA
V
gen
= 560 mV
RC = 68 k
G
R
1.5
+ 0.5
dB
Distortion at low
operating current
I
L
= 10 mA, I
D
= 1 mA
V
gen
= 560 mV
RC = 68 k
dr
5
%