w91030b Winbond Electronics Corp America, w91030b Datasheet - Page 6

• Manufacturer Part Number: w91030b
• Description: Calling Line Identifier
• Manufacturer: Winbond Electronics Corp America

FUNCTIONAL DESCRIPTION
Figure 6 is shown functional blocks of W91030B. The device must operate with a 3.579545 MHz
system clock and consists four major functions and decribed as follows:
Ring Detector
The application circuit in Figure 7-1 illustrates the relationship between the RNGDI, RNGRC and
RNGON signals. The three pin combination is used to detect an increase of the RNGDI voltage from
ground to a level above the Schmitt trigger high going threshold voltage V
The RC time constant of the RNGRC pin is used to delay the output pulse of the RNGON pin for a
low going edge on RNGDI. This edge goes from above the V
going threshold voltage V
ring signal, to ensure a minimum RNGON low interval and to filter the ring signal to get an envelope
output.
Allowance minimal ring voltage (peak to peak) is:
Tolerance to noise between Tip and Ring and Vss is:
Vpp
Vpeak
Time constant is:
T = R5 C3 ln [V
V
T+(min)
Ring/B
Tip/A
(max ring)
(max noise)
<= V
C1 = 0.1uF
= 2 (V
DD
T+
C1 = 0.1 uF
T-
= V
<= V
/ (V
. The RC time constant must be greater than the maximum period of the
T+(max)
T+(min)
DD
T+(max)
Figure 7-1. Application Circuit of the Ring Detecter
- V
R1 = 470K
R2 = 470 K
T+
(R1 + R3 + R4) / R4 + 0.7)
(R1 + R3 + R4) / R4 + 0.7
)]
R3 = 200 K
- 6 -
C3 = 0.22 uF
R5 = 150 K
R4 = 300 K
V
DD
V
DD
R5 from 10K ohm to 500K ohm.
C3 from 47 nF to 0.68 uF.
RNGON
RNGRC
RNGDI
Preliminary W91030B
T+
voltage to the Schmitt trigger low
W91030B
T+
.