TEA7092TQ Просмотр технического описания (PDF) - STMicroelectronics
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TEA7092TQ Datasheet PDF : 24 Pages
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TEA7092
LOUDSPEAKER AMPLIFIER PART (continued)
Antiacoustic Feedback (Tamb = 25°C, IL = 20mA, see Test 4)
The antiacoustic feedback system is coupled to the microphone squelch. As soon as the level on the handset
microphone is higher than VT2, the transmit gain increases and the loudspeaker gain decreases. So the transmit
and loudspeaker gains are never simultaneously at maximum gain, which reduces larsen effect.
Symbol
Dgls(0)
Dgls(1)
Dgls(2)
Dgls(3)
Parameter
Antiacoustic Feedback Efficiency
Test Conditions
Code 0111100
Code 0111101
Code 0111110
Code 0111111
Min. Typ. Max. Unit
-12 -9.5
-7
dB
-17 -14.5 -12
dB
-21.5 -18.5 -15.5 dB
-26.5 -22.5 -18.5 dB
Figure 5 : Loudspeaker Gain GLS versus Voltage on Microphone
Gtr (dB)
Gmax
Gma x - 9dB
GLS
GLS - xdB
Low Microphone
Le vel
Normal Spee ch
9dB
High Microphone S igna l
S oftclipping Mode
3dB
VT1
VT2
VSOFT
VMIC
GLS is P rogramma ble through the Volum e Control S ta g e
x is P rogramma ble through the S e rial Bus
(10, 15, 20, 25dB) (de fault va lue is 15dB)
VMIC
RING MODE
Loudspeaker Power Supply in Ring Mode (Tamb = 25°C, RLS = 50Ω, see Test 5)
In ring mode, it is neccessary to convert the high voltage / low current power input to a low voltage / high
current power, output to be able to drive a 50Ω loudspeaker,the external switch mode power supply driven
by the TEA7092 realizes this feature.
The switch mode power supply, through external component values, fixes the impedance and the start up
threshold level.
The volume control in ring mode is the same than the one used in loudspeaking mode for the highest steps,
8 steps of 4dB, and 5 more steps of 4dB each have been added, by using the code 0111011, for the lowest
one, by this way the maximum depth in ring mode for the volume control is 48dB.
Symbol
ILEAK1
ILEAK2
IRON1
IVRSU
VLS1
VRMC1
VRI1
VRES1
VLS2
VRMC2
VRI2
VRES2
VOUT
Parameter
Leackage Current
Input Current
Start up Current
LS Supply
Stabilized Microprocessor Supply
Ring Indicator Output
Reset Output
LS Supply
Stabilized Microprocessor Supply
Ring Indicator Output
Reset Output
LS Output Level
Test Conditions
Min. Typ. Max. Unit
VRING = 16V, I(VZP) = 0
VRING = VRSU = 22V, I(VZP) = 20µA
40 150 µA
130 400 µA
10
12 mA
VRING = 22V
I(VZP) = 140µA, I(VLS) = 40mA
No code sent, no signal on the
loudspeaker output
60 150 µA
2.8 3.05 3.5
V
2.75 3
V
2.7 2.95
V
2.7 2.95
V
VRING = 22V, I(VZP) =250µA,
Gain = Gain Max.,
Codes sent :
- Group listening
- FI = 26321Hz & n = 60
- Ring start
5
5.4
V
3
3.4 3.75 V
2.9 3.3
V
2.9 3.3
V
5
5.4
VPP
Ring Frequency
The frequencies of the ring are given by : Fring = Fni.
Fi can take one of the following values : 19455Hz, 21308Hz, 23551Hz or 26321Hz, and n varies between
1 and 63. Fi and n correspond to 2 codes sent on the serial bus.
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