CPC5712 Datasheet, PDF (7/11 Pages) Clare, Inc. – Phone Line Monitor with Detectors (PLMD)

INTEGRATED CIRCUITS DIVISION
3. Design Example
An application circuit that is based on information
discussed in Section 2.5 “Detector Threshold
Operation” on page 6 is shown in Figure 1.
In the following telephony design example, it is desired
to have a Line-In-Use (LIU) detector set at 12V with a
hysteresis of 3V, and a loop or battery-presence
(LOOP) detector set at 5V with a hysteresis of 2V. The
CPC5712
LIU detector will monitor the Public Switched
Telephone Network (PSTN) twisted pair TIP and RING
leads for a voltage level that indicates a device on the
line is off-hook while the LOOP detector monitors for
the presence of battery feed. In this example
detector 2 (DET2) will be the LIU detector as it has the
greater voltage detect thresholds.
Figure 1 CPC5712 Application Circuit
TIP
RING
V+
0.1µF
1
V_CC
CPC5712
(4)
10M
1%
1206
7 IN+ ₊
806K
1%
G=5
- ^{8 IN-}
OUT+ 5
OUT - 6
GND
V_REF
16 15 14 9
POLARITY 4
OUT+
DET1 3
V_L1
V_H1 V_L2
V_H2
DET2 2
10 11 12 13
R1
26.7K
1%
R2 R3 R4 R5
17.8K 61.9K 26.7K 137K
1% 1% 1% 1%
+ Analog Output
− Analog Output
Polarity Output
Voltage Level Detect 1
Voltage Level Detect 2
R02
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