LUCL9310AP-D AGERE [Agere Systems], LUCL9310AP-D Datasheet - Page 47

• Manufacturer Part Number: LUCL9310AP-D
• Description: Line Interface and Line Access Circuit Full-Feature SLIC,Ringing Relay,and Test Access Device
• Manufacturer: AGERE [Agere Systems]

July 2001
Agere Systems Inc.
ac Applications
First-Generation Codec ac Interface Network: Resistive Termination
Example 1, Real Termination
The following design equations refer to the circuit in Figure 15. Use these to synthesize real termination imped-
ance.
Termination Impedance:
Receive Gain:
Transmit Gain:
Hybrid Balance:
To optimize the hybrid balance, the sum of the currents at the VFX input of the codec op amp should be set to 0.
The expression for ZHB becomes:
(continued)
Z
g
g
rcv
T
Full-Feature SLIC, Ringing Relay, and Test Access Device
rcv
g
h
=
t x
bal
=
g
R
=
76
t x
=
H B
= 20 log
------------------------------------------------------------------
V
----------- -
V
h
1
=
–
-------- -
T/R
FR
R
bal
+
R
k
T 6
V
---------- -
V
+
X
= 20 log
R
-----------
GSX
R
T/R
Z
2
R C V
T
T 3
R
-------- -
Z
300
=
=
T/R
-------------- -
R
P
+
R
------------------ -
g
+
H B1
------------
–
V
t x
I
X
R
----------- -
T/R
R
T/R
---------------------------------- -
1
R
8
R C V
V
-------------- -
G P
+
–
V
X
g
GSX
g
-------- -
R
R
FR
rcv
tx
2400
G P
T 3
1
g
+
+
rcv
----------- -
R
-------- -
Z
R
Z
R C V
T/R
T3
T
(continued)
47