參數(shù)資料
型號(hào): TEA1098
廠商: NXP Semiconductors N.V.
英文描述: Speech and handsfree IC
中文描述: 免提語音和集成電路
文件頁數(shù): 13/40頁
文件大?。?/td> 199K
代理商: TEA1098
1999 Oct 14
13
Philips Semiconductors
Product specification
Speech and handsfree IC
TEA1098
L
OUDSPEAKER CHANNEL
Loudspeaker amplifier: pins HFRX, GALS and LSAO
The TEA1098 loudspeaker amplifier has an asymmetrical
inputwithaninputresistanceof20 k
betweenpinsHFRX
and GND. It is biased at a voltage of two diodes. Without
output limitation, the input stage can accept signals of up
to 580 mV (RMS) at 2% THD (room temperature).
The gain of the input stage varies according to the
TEA1098 mode. In Rx mode, it has maximum gain; in
Tx mode, it has minimum gain and in Idle mode, it is
halfway between maximum and minimum gain.
Switch-over from one mode to the other is smooth and
click-free.Therail-to-railoutputstageisdesignedtopower
aloudspeakerconnectedasasingle-endedload(between
pins LSAO and GND).
In Rx mode, the overall gain of the loudspeaker amplifier
can be adjusted from 0 up to 35 dB to suit specific
application requirements. The gain from pin HFRX to pin
LSAO is proportional to the value of R
GALS
and is 28 dB
when R
GALS
is 255 k
. It is recommended that a capacitor
is connected in parallel with R
GALS
to provide a first-order
low-pass filter.
Volume control: pin VOL
The loudspeaker amplifier gain can be adjusted by the
potentiometer R
VOL
. For logarithmic gain control, a linear
potentiometer can be used. Each 1.9 k
increase of R
VOL
results in a gain loss of 3 dB. The maximum gain reduction
using the volume control is internally limited to the
switching range (see Fig.9).
handbook, full pagewidth
MGL343
DYNAMIC
LIMITER
VOLUME
CONTROL
I V
V I
DLC
LSAO
GALS
VOL
HFRX
14
(11)
15
(12)
12
(8)
5
(1)
26
(23)
VBB
RGALS
CGALS
CLSAO
CDLC
RVOL
to
logic
to/from
voice switch
to
envelope
detector
Fig.9 Loudspeaker channel.
Pin numbers in parenthesis apply to the TEA1098H. Pin numbers not in parenthesis apply to the TEA1098TV.
Dynamic limiter: pin DLC
The TEA1098 dynamic limiter prevents clipping of the
loudspeaker output stage and protects the operation of the
circuit when the supply voltage at V
BB
falls below 2.7 V.
Hard clipping of the loudspeaker output stage is prevented
by rapidly reducing the gain when the output stage starts
to saturate. The time taken to effect gain reduction
(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 (typically
250 ms). Both attack and release times are proportional to
the value of the capacitor C
DLC
.
The total harmonic distortion of the loudspeaker output
stage, in reduced gain mode, stays below 2% up to 10 dB
(minimum) of input voltage overdrive [providing V
HFRX
is
below 580 mV (RMS)].
When the supply voltage falls below an internal threshold
voltage of 2.7 V, the gain of the loudspeaker amplifier is
reduced rapidly (approximately 1 ms). When the supply
voltage rises above 2.7 V, the gain of the loudspeaker
amplifier is increased. By forcing a level lower than 0.2 V
on pin DLC, the loudspeaker amplifier is muted and the
TEA1098 is automatically forced into the Tx mode.
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TEA1098A 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Speech and handsfree IC
TEA1098AH 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Speech and handsfree IC
TEA1098ATV 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Speech and handsfree IC
TEA1098H 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Speech and handsfree IC
TEA1098TV 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Speech and handsfree IC