|TEA1114AUH||Low voltage telephone transmission circuit with dialler interface and regulated strong supply|
|TEA1114AUH Datasheet PDF : 28 Pages |
Low voltage telephone transmission circuit with
dialler interface and regulated strong supply
handbook, full pagewidth Rline
Fig.6 VDD regulator configuration.
In the audio frequency range, the dynamic impedance is
mainly determined by the RCC resistor. The equivalent
impedance of the circuit is illustrated in Fig.7.
LEQ = CREG × RSLPE × RP.
RP = internal resistance.
RP = 17.5 kΩ.
Fig.7 Equivalent impedance between LN and VEE.
Transmit stage (pins MIC+, MIC− and DTMF)
MICROPHONE AMPLIFIER (PINS MIC+ AND MIC−)
The TEA1114A has symmetrical microphone inputs.
The input impedance between pins MIC+ and MIC− is
64 kΩ (2 × 32 kΩ). The voltage gain from pins MIC+/MIC−
to pin LN is set at 44.2 dB (typically).
Automatic gain control is provided on this amplifier for line
DTMF AMPLIFIER (PIN DTMF)
When the DTMF amplifier is enabled, dialling tones may
be sent on line. These tones are also sent to the receive
output RX at a low level (confidence tone).
The TEA1114A has an asymmetrical DTMF input.
The input impedance between DTMF and VEE is 20 kΩ.
The voltage gain from pin DTMF to pin LN is set at 26 dB.
Automatic gain control has no effect on the DTMF
2000 Mar 21
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