CPC5622
2. Application Circuits
LITELINK can be used with telephone networks
worldwide. Some public telephone networks, notably
in North America and Japan require a resistive line
termination. Other telephone networks as in Europe,
China and elsewhere require reactive line termination.
The application circuits that follow address both types
of line termination models. A reactive termination
application circuit that describes a TBR-21
implementation is shown
This
circuit can be easily adapted for other reactive
termination needs.
2.1 Resistive Termination Application Circuit
Figure 3. Resistive Termination Application Circuit Schematic
3.3 or 5V
R23
2
10
C16
10µ
A
C1
1µ
FB1
600
Ω
200 mA
A
U1
R1
(R
TX
)
80.6K
1 VDD
2 TXSM
3 TX-
4 TX+
5 TX
6 MODE
A
LITELINK
REFL
TXF
ZTX
ZNT
TXSL
BR-
NTS
32
31
30
29
28
27
26
C9
0.1µ
BR-
TX-
TX+
C13
C2
0.1µ
0.1µ
R5
(R
TXF
)
60.4K
BR-
R75
(R
NTX
)
261K
C10
0.01µ
500V
R13
(R
NTS
)
1M
7 GND
8 OH
9 RING
10 RING2
OH
RING
RING2
RX-
RX+
C14
C4
GAT 25
NTF
24
R22
(R
DCS1A
)
6.49M
R21
(R
DCS1B
)
6.49M
C12
(C
DCS
)
0.027µ
BR-
R14
(R
GAT
)
47
5%
R12
(R
NTF
)
499K
Q1
CPC5602C
C15
0.01µ
500V
BR-
C21
100p
BR-
(C
GAT
)
DCS1 23
DCS2
22
0.1µ 11
RX-
0.1µ 12
RX+
13 SNP+
14 SNP-
15 RXF
16 RX
R2
(R
RXF
)
130K
R15
(R
DCS2
)
1.69M
ZDC 21
BR- 20
RPB
RXS
VDDL 17
R4
(R
PB
)
68.1
BR-
R20
(R
VDDL
)
2
5%
+
R16 (R
3
ZDC
)
8.2
BR-
R76 (R
HTF
)
200K
R8
221K (R
HTX
)
DB1
TIP
19
18
-
R18
(R
ZTX
)
3.32K
BR-
BR-
C18
15p
3
R10
(R
ZNT
)
301
BR-
SP1
1
RING
C7
(C
SNP-
)
4
220p
R3
(R
SNPD
)
1.5M
C8
(C
SNP+
)
4
220p
R6
(R
SNP-2
)
1.8M
R7
(R
SNP+2
)
1.8M
R44
(R
SNP-1
)
1.8M
R45
(R
SNP+1
)
1.8M
NOTE: Unless otherwise noted:
Resistor values are in Ohms
All resistors are 1%.
Capacitor values are in Farads.
¹This design was tested and found to comply with FCC Part 68 with this
Sidactor. Other compliance requirements may require a different part.
²Higher-noise power supplies may require substitution of a 220
µH
inductor,
Toko 380HB-2215 or similar. See the Power Quality section of Clare
application note AN-146,
for
more information.
³Optional for enhanced transhybrid loss.
4
Use
voltage ratings based on the isolation requirements of your application.
6
www.clare.com
Rev. 1.0
CLARE [ CLARE, INC. ]
