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INTEGRATED CIRCUITS
DATA SHEET
TDA9830
TV sound AM-demodulator and audio source switch
Product specification |
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June 1994 |
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File under Integrated Circuits, IC02 |
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Philips Semiconductors |
Product specification |
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TV sound AM-demodulator and audio source switch |
TDA9830 |
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FEATURES
∙Adjustment free wideband synchronous AM demodulator
∙Audio source-mute switch (low noise)
∙Audio level according EN50049
∙5 to 8 V power supply or 12 V alternative
∙Low power consumption.
GENERAL DESCRIPTION
The TDA9830, a monolithic integrated circuit, is designed for AM-sound demodulation used in L- and L’-standard. The IC provides an audio source selector and also mute switch.
QUICK REFERENCE DATA
SYMBOL |
PARAMETER |
MIN. |
TYP. |
MAX. |
UNIT |
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V14 |
positive supply voltage |
4.5 |
5.0 |
8.8 |
V |
V11 |
supply voltage (alternative) |
10.8 |
12.0 |
13.2 |
V |
I14,11 |
supply current |
24 |
30 |
36 |
mA |
V1−16 |
IF sensitivity (RMS value) (for −3 dB AF-signal) |
− |
60 |
100 |
μV |
Gv |
gain control |
60 |
66 |
− |
dB |
V6 |
AF output signal (m = 54%) (RMS value) |
400 |
500 |
600 |
mV |
V6 |
S/N ratio acc. CCIR468-3 (IF-signal 10 mVRMS) |
47 |
53 |
− |
dB |
V7,9 |
AF input signal (for THD < 1.5%) (RMS value) |
− |
− |
1.2 |
V |
V8 |
crosstalk and mute attenuation |
80 |
90 |
− |
dB |
Tamb |
operating ambient temperature |
0 |
− |
+70 |
°C |
ORDERING INFORMATION
EXTENDED TYPE NUMBER |
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PACKAGE |
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PINS |
PIN POSITION |
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MATERIAL |
CODE |
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TDA9830 |
16 |
DIL |
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plastic |
SOT38GG(1) |
TDA9830T |
16 |
SO |
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plastic |
SOT109(2) |
Note
1.SOT38-1; 1996 November 20.
2.SOT109-1; 1996 November 20.
June 1994 |
2 |
Philips Semiconductors |
Product specification |
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TV sound AM-demodulator and audio
TDA9830
source switch
Fig.1 Block diagram.
June 1994 |
3 |
Philips Semiconductors |
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Product specification |
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TV sound AM-demodulator and audio source switch |
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TDA9830 |
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PINNING |
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SYMBOL |
PIN |
DESCRIPTION |
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IFIN |
1 |
sound IF differential input signal |
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n.c. |
2 |
not connected |
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CAGC |
3 |
AGC capacitor |
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CREF |
4 |
REF voltage filtering capacitor |
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n.c. |
5 |
not connected |
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AMOUT |
6 |
AM demodulator output |
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AMIN |
7 |
input signal (from AM) to audio switch |
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AFOUT |
8 |
output signal from audio switch |
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EXTIN |
9 |
input signal (from external) to audio switch |
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SWITCH |
10 |
switch input select control |
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Vp2 |
11 |
supply voltage +12 V (alternative) |
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MUTE |
12 |
mute control |
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GND |
13 |
ground (0 V) |
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Vp1 |
14 |
supply voltage +5 to +8 V |
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n.c. |
15 |
not connected |
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Fig.2 |
Pin configuration. |
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IFIN |
16 |
sound IF differential input signal |
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FUNCTIONAL DESCRIPTION
Sound IF input
The sound IF amplifier consists of three AC-coupled differential amplifier stages each with approximately 20 dB gain. At the output of each stage is a multiplier for gain controlling (→ current distribution gain control). The overall control range is approximately −6 to +60 dB and the frequency response (−3 dB) of the IF amplifier is approximately 6 to 70 MHz. The steepness of gain control is approximately 10 mV/dB.
IF AGC
The automatic gain control voltage to maintain the AM demodulator output signal at a constant level is generated by a mean level detector. This AGC-detector charges and discharges the capacitor at pin 3 controlled by the output signal of the AM-demodulator compared to an internal reference voltage. The
maximum charge/discharge current is approximately 5 μA. This value in combination with the value of the AGC capacitor and the AGC steepness determines the lower cut-off audio frequency and the THD-figure at low modulation frequency of the whole AM-demodulator. Therefore a large time constant has to be chosen which leads to slow AGC reaction at IF level change. To speed up the AGC in case of IF signal jump from low to high level, there is an additional comparator built in, which can provide additional discharge current from the AGC capacitor up to 5 mA in a case of overloading the AM demodulator by the internal IF signal.
AM-demodulator
The IF amplifier output signal is fed to a limiting amplifier (two stages) and to a multiplier circuit. However the limiter output signal (which is not any more AM modulated) is also fed to the multiplier, which provides AM
demodulation (in phase demodulation). After lowpass filtering (fg ≈ 400 kHz) for carrier rejection and buffering, the demodulator output signal is present at pin 6. The AM demodulator operates over a wide frequency range, so that in combination with the frequency response of the IF amplifier applications in a frequency range from approximately 6 MHz up to
70 MHz are possible.
Audio switch
This circuit is an operational amplifier with three input stages and internal feedback network determining gain (0 dB) and frequency response
(fg ≈ 700 kHz). Two of the input stages are connected to pin 7 and pin 9, the third input stage to an internal reference voltage. Controlled by the switching pins 10 and 12, one of the three input stages can be activated and a choice made between two different AF signals or mute state. The selected signal is present at
June 1994 |
4 |
Philips Semiconductors |
Product specification |
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TV sound AM-demodulator and audio source switch |
TDA9830 |
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pin 8. The decoupling capacitors at the input pins are needed, because the internally generated bias voltage for the input stages must not be influenced by the application in order to avoid DC-plop in case of switching.
The AM demodulator output is designed to provide almost the same DC voltage as the input bias voltage of the audio switch. But there may be spread between both voltages. Therefore it is possible to connect pin 6 directly to pin 7 (without a decoupling capacitor), but in this event the DC-plop for switching can increase up to 100 mV.
LIMITING VALUES
Reference circuit
This circuit is a band gap stabilizer in combination with a voltage regulation amplifier, which provides an internal reference voltage of about 3.6 V nearly independent from supply voltage and temperature. This reference voltage is filtered by the capacitor at pin 4 in order to reduce noise. It is used as a reference to generate all important voltages and currents of the circuit.
For application in 12 V power supply concepts, there is an internal voltage divider in combination with a
In accordance with the Absolute Maximum Rating System (IEC134).
Darlington transistor in order to reduce the supply voltage for all IC function blocks to approximately 6 V. This is necessary because of use of modern high frequency IC technology, where most of the used integrated components are only allowed to operate at maximum 9 V supply voltage.
SYMBOL |
PARAMETER |
MIN. |
MAX. |
UNIT |
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V14−13 |
supply voltage VP1 |
−0.5 |
+8.9 |
V |
V11−13 |
supply voltage VP2 |
−0.5 |
+13.3 |
V |
V10, 12−13 |
switching voltage |
−0.5 |
VP + 0.5 |
V |
Tamb |
operating ambient temperature |
0 |
+70 |
°C |
Tstg |
storage temperature |
−25 |
+150 |
°C |
Note to the limiting values
1.To avoid an inadmissible increase of ambient temperature, it is not allowed to short-circuit pin 11 for more than 10 seconds to ground.
THERMAL RESISTANCE
SYMBOL |
PARAMETER |
THERMAL RESISTANCE |
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Rth j-a |
from junction to ambient in free air |
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SOT38 |
74 K/W |
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SOT109 |
100 K/W |
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June 1994 |
5 |
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