TEA1093T Philips Semiconductors, TEA1093T Datasheet - Page 9

• Manufacturer Part Number: TEA1093T
• Description: Hands-free IC
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Loudspeaker channel
L
AND
The TEA1093 has symmetrical inputs for the loudspeaker
amplifier with an input resistance of 40 k between RIN1
and RIN2 (2
signals up to 390 mV (RMS) at room temperature for 2% of
total harmonic distortion (THD). The gain of the input stage
varies according to the mode of the TEA1093. In the
receive mode, the gain is at its maximum; in the transmit
mode, it is at its minimum and in the idle mode, it is halfway
between maximum and minimum. Switch-over from one
mode to the other is smooth and click-free. The rail-to-rail
output stage is designed to power a loudspeaker which is
connected as a single-ended load (between LSP1 and
GND) or as a bridge-tied load (between LSP1 and LSP2).
In the receive mode, the overall gain of the loudspeaker
amplifier can be adjusted from 3 dB up to 39 dB to suit
specific application requirements. The gain from RIN1 or
RIN2 to LSP1 is proportional to the value of R
equals 18 dB with R
LSP2 is in opposite phase with LSP1. Therefore, in the
basic application, the gain between RIN1-RIN2 to
LSP1-LSP2 equals 24 dB typical with R
A capacitor connected in parallel with R
provide a first-order low-pass filter.
1996 Feb 09
handbook, full pagewidth
OUDSPEAKER AMPLIFIER
Hands-free IC
LSP2
C LSP1
20 k ). The input stage can accommodate
R GAR
C DLC
GAR
:
= 66.5 k . The second output
PINS
5
6
1
4
DLC/MUTER
LSP2
GAR
LSP1
RIN1, RIN2, GAR, LSP1
from voltage
stabilizer
GAR
GAR
DYNAMIC
LIMITER
can be used to
= 66.5 k .
Fig.7 Loudspeaker channel.
GAR
and
1
9
V
The loudspeaker amplifier gain can be adjusted with the
potentiometer R
obtain logarithmic control of the gain at the loudspeaker
amplifier. Each 950
loss of 3 dB. The maximum gain reduction with the volume
control is internally limited to the switching range.
D
The dynamic limiter of the TEA1093 prevents clipping of
the loudspeaker output stages and protects the operation
of the circuit when the supply condition falls below a
certain level.
Hard clipping of the loudspeaker output stages is
prevented by rapidly reducing the gain when the output
stages start to saturate. The time in which gain reduction
is effected (clipping attack time) is approximately a few
milliseconds. The circuit stays in the reduced gain mode
until the peaks of the loudspeaker signals no longer cause
saturation. The gain of the loudspeaker amplifier then
returns to its normal value within the clipping release time
(typical 250 ms). Both attack and release times are
proportional to the value of the capacitor C
harmonic distortion of the loudspeaker output stages, in
reduced gain mode, stays below 5% up to 10 dB
(minimum) of input voltage overdrive [providing V
below 390 mV (RMS)].
V
OLUME CONTROL
YNAMIC LIMITER
I
logic
to
voice switch
VOL
:
to/from
:
PIN
PIN
. A linear potentiometer can be used to
CONTROL
VOLUME
I
DLC/MUTER
VOL
increase of R
V
envelope
detector
to
RIN1 2
RIN2
VOL
11
3
VOL
MGD222
Product specification
results in a gain
R VOL
TEA1093
from
TEA106X
DLC
. The total
RIN
is