TEA1112AT NXP Semiconductors, TEA1112AT Datasheet - Page 9

• Manufacturer Part Number: TEA1112AT
• Manufacturer: NXP Semiconductors

Specifications of TEA1112AT

• Max Transmitter Gain: 53dB
• Receiver Gain (max): 32.7dB
• Operating Temp Range: -25C to 75C
• Package Type: SSOP
• Pin Count: 16
• Operating Current: 1.15mA
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Lead Free Status / Rohs Status: Not Compliant

Philips Semiconductors
MUTE and MMUTE levels for different modes
Table 1 Required MUTE and MMUTE levels to enable the different possible modes
SIDETONE SUPPRESSION
The TEA1112; TEA1112A anti-sidetone network
comprising R
(see Fig.10) suppresses the transmitted signal in the
earpiece. Maximum compensation is obtained when the
following conditions are fulfilled:
The scale factor k is chosen to meet the compatibility with
a standard capacitor from the E6 or E12 range for Z
In practice, Z
the line length. Therefore, the value chosen for Z
1997 Mar 26
R
k
Z
handbook, full pagewidth
Mode
Speech
DTMF dialling
Microphone mute
bal
SLPE
Low voltage versatile telephone
transmission circuits with dialler interface
=
---------------------------------------------------------------------- -
=
R
k Z
ast2
R
ast1
R
line
line
CC
ast1
R
=
varies considerably with the line type and
// Z
IC
ast3
R
R
line
CC
SLPE
Fig.10 Equivalent circuit of TEA1112; TEA1112A family anti-sidetone bridge.
+
, R
R
SLPE
ast1
R
ast2
, R
ast2
+
Z line
V EE
R
, R
ast3
ast3
, R
R SLPE
MUTE
SLPE
R CC
H
L
L
bal
and Z
should
TEA1112
bal
SLPE
LN
bal
.
I m
R ast3
9
be for an average line length which gives satisfactory
sidetone suppression with short and long lines.
The suppression also depends on the accuracy of the
match between Z
line.
The anti-sidetone network for the TEA1112; TEA1112A
(as shown in Fig.14) attenuates the receiving signal from
the line by 32 dB before it enters the receiving amplifier.
The attenuation is almost constant over the whole audio
frequency range. A Wheatstone bridge configuration (see
Fig.11) may also be used.
More information on the balancing of an anti-sidetone
bridge can be obtained in our publication “Applications
Handbook for Wired Telecom Systems, IC03b” , order
number 9397 750 00811.
MMUTE
R ast1
H
X
L
Z bal
R ast2
IR
MBE787
bal
Z ir
and the impedance of the average
MUTE
TEA1112; TEA1112A
H
H
L
TEA1112A
Product specification
MMUTE
H
X
L