W91030 Ver la hoja de datos (PDF) - Winbond

Número de pieza

componentes Descripción

Fabricante

W91030

CALLING LINE IDENTIFIER

Winbond 

Preliminary W91030B

The diode bridge shown in Figure 7-1 works for both single ended ring signal and balanced ringing.

R1 and R2 are used to set the maximum loading and must be of equal value to achieve balanced

loading at both the tip and ring line. R1, R3 and R4 form a resistor divider to supply a reduced voltage

to the RNGDI input. The attenuation value is determined by the detection of minimal ring voltage and

maximum noise tolerance between tip/ring and ground.

Input Pre-processor

The input signal is processed by an Input Pre-Processor, which is added to the offset voltage to adjust

the input amplitude and to filter out unwanted frequencies. The gain control op-amp is used to bias

the input voltage with the VREF signal voltage. The voltage of VREF pin is VDD/2 typically, this pin

had better connected a 0.1uF capacitor to VSS. It is also used to select the input gain by connecting a

feedback resistor between this pin and the INN pin. Figure 7-2 shows the necessary connections with

the tip/ring line inputs. In a single-ended configuration, the gain control op-amp is connected as

shown in Figure 7-3.

C1

R1

Tip

Ring

C2

R2

W91030B

VREF

0.1 uF

R3

R4

INP

+

INN

-

R5 GCFB

Differential Input Amplifier

C1 = C2

R1 = R2

R3 = (R4 R5) / (R4 +R5)

Voltage Gain

Av = R5 / R1

Input Impedance

Zin = 2 R12 + (1 / wC)2

Input C

R1

Voltage Gain

A V = R2 / R1

W91030B

VREF

0.1 uF

INP

+

INN

-

R2 GCFB

Figure 7-2 Differential Input Gain Control Circuit

Figure 7-3 Single-ended Input Gain Control Circuit

Dual Tone Alert Signal Detection

The dual tone alert signal is separated into high and low tones and detected by a high/low tone

detector. The dual tone alert signal detection circuit is always enabled when the W91030B/BS is not

in sleep state. The ALGR is the output of the dual tone detector and when high indicates that the high

tone and low tone alert signals have been detected. The guard time improves detection performance

by rejecting detected signals with insufficient duration and by masking momentary detection dropout.

Figure 7-4 shows the relationship between the ALGR, ALGRC and ALGO pins and Figure 7-5 shows

the guard time waveform of the same pins. The total recognition time is tREC = tDP + tGP, where tDP is

the tone present detect time and tGP is the tone present guard time. The tone present guard time is

the RC time constant with the capacitor discharging from VSS to VDD ( the ALGRC pin discharges

from VSS to VDD through a resistor). The capacitor will discharge rapidly via a discharge switch after

ALGO returns high. The total absent time is tABS = tDA + tGA, where tDA is the tone absent detect time

and tGA is the tone absent guard time. The tone absent guard time is the RC time constant with the

Publication Release Date: March 2000

-7-

Revision A1

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