U4050B Datasheet, PDF (1/18 Pages) TEMIC Semiconductors – Speech Circuit with Line-Powered Loudspeaker Amplifier

U4050B
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
GS
MICO TIN ST
GR
RECO1
RECO2
8
DTMF
MIC1 ¹⁰
MIC2 ¹¹
9
7
15
4
+
–
–
+
2
3
–
+
SAI
1
26 ^GSA
SA
21 ^SAO
12
LEVSQ
CSQ ^{13 SQUELCH}
TXA
AGA
LIMSA
REC. ATT.
17 ^CLISA
AGA
27
6 ^CK
LIMITER
5
CLIM
MUTE
NSA
Power supply
U4050B
16
25
22
28
18
14
20
MUTE
PD
GND IREF SWAMP VM
VD
Figure 1. Block diagram
23 ^VL
19 ^RDC
24 ^VC
Ordering Information
Extended Type Number
U4050B-AFL
U4050B-AFLG3
Package
SO28
SO28
Remarks
Taped and reeled
Rev. A2, 05-Mar-98
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