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TEA1110 データシート(PDF) 6 Page - NXP Semiconductors |
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TEA1110 データシート(HTML) 6 Page - NXP Semiconductors |
6 / 20 page 1997 Apr 22 6 Philips Semiconductors Product specification Low voltage versatile telephone transmission circuit with dialler interface TEA1110A Set impedance 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. Microphone amplifier (pins MIC+ and MIC −) The TEA1110A has symmetrical microphone inputs. The input impedance between pins MIC+ and MIC − is 64 k Ω (2 × 32 kΩ). The voltage gain from pins MIC+/MIC− to pin LN is set at 43.7 dB (typ). Automatic gain control is provided on this amplifier for line loss compensation. Receiving amplifier (pins IR, GAR and QR) The receiving amplifier has one input (IR) and one output (QR). The input impedance between pin IR and pin VEE is 20 k Ω. The voltage gain from pin IR to pin QR is set at 33 dB (typ). The gain can be decreased by connecting an external resistor RGAR between pins GAR and QR; the adjustment range is 14 dB. Two external capacitors CGAR (connected between GAR and QR) and CGARS (connected between GAR and VEE) ensure stability. The CGAR capacitor provides a first-order low-pass filter. The cut-off frequency corresponds to the time constant CGAR × (RGARint // RGAR). RGARint is the internal resistor which sets the gain with a typical value of 125 k Ω. The condition CGARS =10 × CGAR must be fulfilled to ensure stability. The output voltage of the receiving amplifier is specified for continuous wave drive. The maximum output swing depends on the DC line voltage, the RCC resistor, the ICC current consumption of the circuit, the IP current consumption of the peripheral circuits and the load impedance. Automatic gain control is provided on this amplifier for line loss compensation. Automatic gain control (pin AGC) The TEA1110A performs automatic line loss compensation. The automatic gain control varies the gain of the microphone amplifier and the gain of the receiving amplifier in accordance with the DC line current. The control range is 5.9 dB (which corresponds approximately to a line length of 5 km for a 0.5 mm diameter twisted-pair copper cable with a DC resistance of 176 Ω/km and an average attenuation of 1.2 dB/km). The IC can be used with different configurations of feeding bridge (supply voltage and bridge resistance) by connecting an external resistor RAGC between pins AGC and VEE. This resistor enables the Istart and Istop line currents to be increased (the ratio between Istart and Istop is not affected by the resistor). The AGC function is disabled when pin AGC is left open-circuit. Mute function (pin MUTE) The mute function performs the switching between the speech mode and the dialling mode. When MUTE is LOW, the DTMF input is enabled and the microphone and receiving amplifiers inputs are disabled. When MUTE is HIGH, the microphone and receiving amplifiers inputs are enabled while the DTMF input is disabled. A pull-up resistor is included at the input. DTMF amplifier (pin DTMF) When the DTMF amplifier is enabled, dialling tones may be sent on line. These tones can be heard in the earpiece at a low level (confidence tone). The TEA1110A 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 25.3 dB. The automatic gain control has no effect on the DTMF amplifier. Fig.5 Typical current IP available from VCC for peripheral circuits at Iline = 15 mA. (1) With RVA resistor. (2) Without RVA resistor. handbook, halfpage 2.5 0 01 2 3 4 MBE783 0.5 1 1.5 2 VCC (V) (1) (2) IP (mA) |
同様の部品番号 - TEA1110 |
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同様の説明 - TEA1110 |
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