LUCL9215AAU-D AGERE [Agere Systems], LUCL9215AAU-D Datasheet - Page 40

• Manufacturer Part Number: LUCL9215AAU-D
• Description: Short-Loop Sine Wave Ringing SLIC
• Manufacturer: AGERE [Agere Systems]

Short-Loop Sine Wave Ringing SLIC
ac Applications
Design Examples
Set Z
Transmit Gain
Transmit gain will be specified as a gain from T/R to
PCM, T
assumed to be 0 dB, and in the case of T/R being refer-
enced to some complex impedance other than 600
resistive, the effects of the impedance transformation
must be taken into account.
Again, specified complex termination impedance at T/R
is of the form:
First, calculate the equivalent resistance of this network
at the midband frequency of 1000 Hz.
R
Using R
into account the impedance transformation:
T
40
X
EQ
(dB) = T
---------------------------------------------------------------------------- -
=
2
TG
X
—Gain Shaping (continued)
f
EQ
1
Figure 24. Interface Circuit Using First-Generation Codec (Blocking Capacitors Not Shown)
2
(dB). Since PCM is referenced to 600
+
C
, calculate the desired transmit gain, taking
X (specified[dB])
1 2
2
318.25
R
–I
T/R
f
1
R
2
R
R
2 2
1
2 2
+
C
(continued)
(continued)
R
+ 20log
1 2
1
+
R
R
GX
R
C
R
2
RCVN
RCVP
2
TGS
= 4750
2
+
---------- -
R
600
C
-------------------------------------------------- -
1
EQ
GS
+
2
2
f
R
V
f
TX
2 2
2
R
C
2 2
1
0.1 F
C
5-6396(F)
and
1 2
2
T
XI
T
impedance at the PCM, and R
tip and ring. 20log
loss/gain due to the impedance transformation.
Note in the case of a 600
at T/R 20log
Thus, there is no power loss/gain due to impedance
transformation and T
Finally, convert T
T
The ratio of R
such as T7504:
R
----------
R
R
X (specified[dB])
X
X
R
R
T6
X
20
(dB) = 20log g
< 200 k
N1
N2
= g
C
N
TX
V
ITR
•
318.25
----------------- -
is the specified transmit gain. 600
R
R
X
---------- -
R
600
20
/R
T3
GP
R
R
EQ
T6
RCV
X
T6
TX
(dB) to a ratio, g
= 20log
is used to set the transmit gain:
---------- -
R
600
•
X
EQ
---- -
M
1
(dB) = T
R
HB
represents the power
with a quad Agere codec
–
+
R
OP AMP
CODEC
pure resistive termination
x
600
--------- -
600
EQ
X (specified[dB])
is the impedance at
= 0.
September 2001
CODEC
OUTPUT
DRIVE
AMP
TX
Agere Systems Inc.
:
.
5-6400.P (F)
is the