TEA1064A/C1 Philips Semiconductors (Acquired by NXP), TEA1064A/C1 Datasheet - Page 14

• Manufacturer Part Number: TEA1064A/C1
• Description: TEA1064A; Low Voltage Versatile Telephone Transmission Circuit With Dialler Interface And Transmit Level Dynamic Limiting
• Manufacturer: Philips Semiconductors (Acquired by NXP)

Philips Semiconductors
Table 1 Values of R6 giving optimum line-loss
MUTE input (see notes 1. and 2.)
MUTE = HIGH enables the DTMF input and inhibits the
microphone and receiving amplifier inputs.
MUTE = LOW or open-circuit disables the DTMF input and
enables the microphone and receiving amplifier inputs.
Switching MUTE gives negligible clicks at the telephone
outputs and on the line.
Dual-tone multi-frequency input DTMF (see note 1.)
When the DTMF input is enabled, dialling tones may be
sent on to the line. The voltage gain between DTMF-SLPE
and LN-V
microphone amplifier and varies with R7 in the same way
as the gain of the microphone amplifier. This means that
the tone level at the DTMF input has to be adjusted after
March 1994
handbook, full pagewidth
Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting
V
(V)
exch
EE
compensation at various values of exchange
supply voltage (V
bridge resistance (R
is typ. 26 dB less than the gain of the
36
48
60
Fig.17 Variation of gain as a function of line current with R6 as a parameter; R9 = 20 .
400
84.5
118
X
exch
(dB)
A vd
600
66.5
93.1
X
exch
) and exchange feeding
0
1
2
3
4
5
6
10
); R9 = 20 .
R
R6 (k )
exch
800
X
77.8
97.6
20
( )
30
1000
X
66.5
84.5
R6 =
40
66.5 k
14
50
setting the gain of the microphone amplifier. With
R7 = 68 k
The signalling tones can be heard in the earpiece at a low
level (confidence tone).
Power-down input PD (see notes 1. and 2.)
During pulse dialling or register recall (timed loop break)
the telephone line is interrupted; as a consequence it
provides no supply for the transmission circuit connected
to V
These supply gaps are bridged by the charges in the
capacitors C1 and C15. The requirements on these
capacitors are eased by applying a HIGH level to the PD
input during the time of the loop break. This reduces the
internal supply current I
60 A and switches off the voltage regulator to prevent
discharge via LN and V
A HIGH level at PD also internally disconnects the
capacitor at REG so that the voltage stabilizer has no
switch-on delay after line interruptions. This minimizes the
contribution of the IC to the current waveform during pulse
dialling or register recall.
When the power-down facility is not required, the PD pin
can be left open-circuit or connected to SLPE.
Side-tone suppression
Suppression of the transmitted signal in the earpiece is
obtained by the anti-sidetone network comprising R1//Z
R6 =
93.1 k
CC1
60
or for the peripherals between V
70
the gain is typically 26 dB.
118 k
I line (mA)
80
MGR072
CC2
CC1
90
.
from (typ.) 1.3 mA to (typ.)
Product specification
TEA1064A
CC2
and SLPE.
line
,