Table 2.
Z
T
= 1000
(
Z
2WIN
– 2R
F
)
User-Programmable Components
Where Z
T
is connected between the VTX and RSN pins. The
fuse resistors are R
F
, and Z
2WIN
is the desired 2-wire AC input
impedance. When computing Z
T
, the internal current amplifier
pole and any external stray capacitance between VTX and
RSN must be taken into account.
Where Z
RX
is connected from V
RX
to the RSN pin, Z
T
is
defined above, and G
42L
is the desired receive gain.
Where R
DC1
, R
DC2
, and C
DC
form the network connected to
the RDC pin. R
DC1
and R
DC2
are approximately equal.
Z
L
1000
•
Z
T
-
-
Z
RX
= -----------
•
----------------------------------------------------
G
42L
Z
T
+ 1000
(
Z
L
+ 2R
F
)
2500
R
DC1
+ R
DC2
= --------------
I
FEED
R
DC1
+ R
DC2
C
DC
= 1.5 ms
•
---------------------------------
R
DC1
•
R
DC2
365
-
R
D
= -------- ,
I
T
0.5 ms
-
C
D
= ---------------
R
D
Where R
D
and C
D
form the network connected from RD to –5 V
and I
T
is the threshold current between on hook and off hook.
SLIC Products
13
AMD [ ADVANCED MICRO DEVICES ]
