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TEA1112A 数据表(PDF) 5 Page - NXP Semiconductors |
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TEA1112A 数据表(HTML) 5 Page - NXP Semiconductors |
5 / 20 page 1997 Mar 26 5 Philips Semiconductors Product specification Low voltage versatile telephone transmission circuits with dialler interface TEA1112; TEA1112A FUNCTIONAL DESCRIPTION All data given in this chapter are typical values, except when otherwise specified. Supply (pins LN, SLPE, VCC and REG) The supply for the TEA1112; TEA1112A and their peripherals is obtained from the telephone line. The ICs generate a stabilized reference voltage (Vref) between pins LN and SLPE. This reference voltage is equal to 3.35 V, is temperature compensated and can be adjusted by means of an external resistor (RVA). It can be increased by connecting the RVA resistor between pins REG and SLPE (see Fig.5), or decreased by connecting the RVA resistor between pins REG and LN. The voltage at pin REG is used by the internal regulator to generate the stabilized reference voltage and is decoupled by a capacitor (CREG) which is connected to VEE. This capacitor, converted into an equivalent inductance (see Section “Set impedance”), realizes the set impedance conversion from its DC value (RSLPE) to its AC value (RCC in the audio-frequency range). The voltage at pin SLPE is proportional to the line current. Figure 4 illustrates the supply configuration. The ICs regulate the line voltage at pin LN, and can be calculated as follows: V LN V ref R SLPE I SLPE × + = I SLPE I line I CC – I p – I∗ – I LED I + sh == Where: Iline = line current ICC = current consumption of the IC Ip = supply current for peripheral circuits I* = current consumed between LN and VEE ILED = supply current for the LED component Ish = the excess line current shunted to SLPE (and VEE) via LN. The preferred value for RSLPE is 20 Ω. Changing RSLPE will affect more than the DC characteristics; it also influences the microphone and DTMF gains, the LED supply current characteristic, the gain control characteristics, the sidetone level and the maximum output swing on the line. The internal circuitry of the TEA1112; TEA1112A is supplied from pin VCC. This voltage supply is derived from the line voltage by means of a resistor (RCC) and must be decoupled by a capacitor CVCC. It may also be used to supply peripheral circuits such as dialling or control circuits. The VCC voltage depends on the current consumed by the IC and the peripheral circuits as shown by the formula (see also Figs.6 and 7). RCCint is the internal impedance of the voltage supply point, and Irec is the current consumed by the output stage of the earpiece amplifier. V CC V CC0 R CCint I p I rec – () × – = V CC0 V LN R CC I CC × – = Fig.4 Supply configuration. handbook, full pagewidth LED DRIVER Ish Rp Rd ISLPE REG LN RGASint from pre amp SLPE 45.5 k Ω 15.5 k Ω VEE Vd VCC RCC CVCC ICC CREG RSLPE Vexch Rexch ILED ILED Iline Rline TEA1112 TEA1112A I * IP peripheral circuits 100 µF 4.7 µF 20 Ω 69 k Ω 619 Ω MBE789 |
类似零件编号 - TEA1112A |
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类似说明 - TEA1112A |
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