LUCL8576BP-D AGERE [Agere Systems], LUCL8576BP-D Datasheet - Page 23

• Manufacturer Part Number: LUCL8576BP-D
• Description: Dual Ringing SLIC
• Manufacturer: AGERE [Agere Systems]

May 2001
Applications
ac Design
Receive Gain
Ratios of R
termination and receive gain for the complex case. In
the complex case, additional high-frequency compen-
sation, via C
loss characteristic. For resistive termination, C
and R
resistor.
Determine the receive gain, G
the impedance transformation in a manner similar to
transmit gain.
R
R
Then:
and low-frequency termination
Agere Systems Inc.
X
X
(dB) = R
(dB) = 20log G
N2
Figure 22. ac Interface Circuit Using First-Generation Codec (Including Blocking Capacitors)
are not used and R
Z
RCV
X (specified[dB])
TER(low)
N
(continued)
, R
, R
G
–I
195
N1
T/R
RCV
T1
RCV
(continued)
, and R
, R
=
=
GP
--------------------------------------------
1
----------------------------------------------- -
1
+ 20log
+
will set both the low-frequency
+
----------- -
R
N2
R
R
-------------- -
R
R
1500
GP
T1
, is needed for the return
CVN
RCV
TSP
T1
R
RCV
+
6
AX
RCVN
RCVP
TGS
= 24.4 k
is tied to ground and a
-------------- -
R
+
R
, taking into account
R
---------- -
RCV
600
R
---------------
T1
R
EQ
RCV
C
GP
TGS
+ 2R
V
P
ITR
N
R
R
, R
N2
N1
N1
C
C
B
N
,
Z
ing low frequency (C or C´ is open).
R
These two equations are best solved using a computer
spreadsheet.
Next, solve for the high-frequency return loss compen-
sation circuit, C
There is an input offset voltage associated with nodes
R
this voltage at T/R, the equivalent resistance to ac
ground at R
at R
capacitors). To meet this requirement, R
Hybrid Balance
Set the hybrid cancellation via R
If a +5 V only codec such as an Agere T8503 is used,
dc blocking capacitors must be added as shown in
Figure 22. This is because the codec is referenced to
+2.5 V and the SLIC to ground. With the ac coupling, a
dc bias at T/R is eliminated and power associated with
this bias is not consumed.
TER(low)
P
CVN
R
R
is the series protection resistor.
CVP
T1
GP
R
, R
T2
R
. Refer to Figure 22 (schematic with dc blocking
RCV
CVP
is the specified termination impedance assum-
. To minimize the effect of the mismatch of
CVN
C
R
N
N1
R
N
x R
should be approximately equal to that
C
C
HB
, R
= R
R
C1
C2
HB
N2
N1
L8576B Dual Ringing SLIC
N2
, and R
=
=
CODEC OUTPUT
DRIVE AMP
------------ -
1500
--------------------------------- -
G
2R
1500
------------ -
2R
RCV
–
+
P
R
P
OP AMP
CODEC
N2
R
X
C
X
:
R
------------- -
R
G
TGS
HB
TGS
TGP
TX
.
x R
–
TGP
1
N2
= R
GP
5-8413 (F)
|| R
T1
23
.