W91031 Datasheet, PDF (22/29 Pages) Winbond – LOW POWER CMOS INTERGRATED CIRCUIT

Preliminary W91031
APPLICATION INFORMATION
Application Circuit
The application circuit of the W91031 in Figure 9-1 shows the device being used within a typical CPE
system. Note that only the circuit between the W91031 and the line interface is shown. The gain
control op-amp is set to unity gain to allow the electrical characteristics to be met in this application
circuit. It should also be noted that if a glitch with sufficient amplitude appears on the tip and ring
interface, this will be detected as a ringing input by this circuit.
Tip/A
Ring/B
22nF
430K
V DD
34K
22nF
430K
V DD
34K
464K
53K6 60K4 ^VDD
0.1 uF
V DD
V DD
W91031
INP
VDD
V DD
0.1uF
10K
INN
ALGRC
GCFB
VREF
ALGR
ALGO
R1 R2
TEST1
INTN
0.1uF _470K
VDD
V DD
RNGDI
RNGRC
RNGON
FCDN
FDRN
DATA
0.1uF _470K
200K
300K
150K
0.22uF
MODE
OSCI
OSCO
VSS
DCLK
FSKE
SLEEP/
RESET
TEST2
Must rest by
microcontroller
or by RC pulse.
Resistor must have 1% tolerance.
Resistor may have 5% tolerance.
Crystal is 3.579545MHz with 0.1% frequency tolerance.
R1, R2 must calculated according to the formula of Figure 7-6(a)
for Bellcore or BT application.
FSK 3-wire interface Mode 0 selected.
Figure 9-1. Application Circuit.
Another application circuit for the W91031, which provides common mode rejection of ringing circuit
signals, is shown in Figure 9-2. When the AC voltage between the tip and ring is greater than the
zener diode breakdown voltage, the photo-coupler LED will turn on, driving RNGDI high and thus
detecting a ringing signal. Note however in this case, a glitch on the tip and ring interface is not able
to turn on the photo-coupler and therefore will not be detected as a ringing signal.
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