TEA1098 Philips Semiconductors, TEA1098 Datasheet - Page 10

• Manufacturer Part Number: TEA1098
• Description: Speech and handsfree IC
• Manufacturer: Philips Semiconductors

Philips Semiconductors
P
To reduce consumption during dialling or register recall
(flash), the TEA1098 is provided with a power-down input
(PD). When the voltage on pin PD is LOW, the current
consumption from V
460 A. Therefore a capacitor of 470 F on V
sufficient to power the TEA1098 during pulse dialling or
flash. The PD input has a pull-up structure. In this mode,
the capacitor C
Transmit channels (pins MIC+, MIC , DTMF,
HFTX and LN)
H
AND
The TEA1098 has symmetrical microphone inputs.
The input impedance between pins MIC+ and MIC is
typically 70 k . The voltage gain between pins MIC+/MIC
and LN is set to 44.3 dB. Without output limitation, the
microphone input stage can accept signals of up to
18 mV (RMS) at 2% THD (room temperature).
1999 Oct 14
handbook, full pagewidth
OWER
ANDSET MICROPHONE AMPLIFIER
Speech and handsfree IC
(pA)
I DD
LN)
10
10
10
10
10
10
10
-
10
DOWN MODE
8
7
6
5
4
3
2
1.0
REG
is internally disconnected.
BB
(
PIN
and V
PD)
DD
is reduced to typically
(
1.5
PINS
MIC+, MIC
Fig.6 Current consumption on V
BB
is
10
2.0
The microphone inputs are biased at a voltage of one
diode.
Automatic gain control is provided for line loss
compensation.
DTMF
The TEA1098 has an asymmetrical DTMF input. The input
impedance between DTMF and GND is typically 20 k .
The voltage gain between pins DTMF and LN is set to
25.35 dB. Without output limitation, the input stage can
accept signals of up to 180 mV (RMS) at 2% THD (room
temperature).
When the DTMF amplifier is enabled, dialling tones may
be sent on the line. These tones can be heard in the
earpiece or in the loudspeaker at a low level. This is called
the confidence tone. The voltage attenuation between pins
DTMF and RECO is typically 16.5 dB. This input is
DC biased at 0 V.
The automatic gain control has no effect on these
channels.
AMPLIFIER
DD
.
(
PINS
2.5
DTMF, LN
V DD (V)
AND
Product specification
RECO)
TEA1098
FCA050
3.0