ISL5585 Intersil Corporation, ISL5585 Datasheet - Page 11

• Manufacturer Part Number: ISL5585
• Description: 3.3 Volt Ringing Slic Family For Voice Over Broadband (VOB)
• Manufacturer: Intersil Corporation

Complex Impedance Synthesis
Substituting the impedance programming resistor, R
complex programming network provides complex
impedance synthesis.
The reference designators in the programming network
match the evaluation board. The component R
different design equation than the R
impedance synthesis. The design equations for each
component are provided below.
Substituting EQ 17 for VTX with AUX =0 and ∆I
gives us EQ 26. Note: AUX input is not used.
Substitute EQ 17 into EQ 21
Substitute EQ 26 into EQ 27
Substitute Equation 19 for R
Simplifying
Loop Equation
I
R
R
C
Node Equation
I
V
V
I
X
V
X
X
TR
Series
Parallel
Parallel
R - V
TR
TR
=
=
=
AUX
------------ - +
=
=
V
---------- -
FIGURE 5. COMPLEX PROGRAMMING NETWORK
R
R
TR
TX
–
–
–
=
2V
2V
2V
=
=
+ I
R
133.3
=
IN
1
133.3
C
IN
IN
V
---------- -
X
–
2
R



TX
V
---------



R = 0



at ISL5585 feed amplifiers and load.
NETWORK
--------- -
R
⁄
at ISL5585 AUX input, Figure 4
R
--------- -
R
R
--------- -
R
R
IN
R
133.3
2-WIRE
·
IN
×
IN
S
IN
S
S
×



C
(
R






--------- -
R



R
R
R
2
2
+
+
IN
+
1
S
2






–






2V
--------------------- -
2V
--------------------- -
V
---------- -
–
2 R
Z



2w
(
2w
Z
L
V
----------------- -
Z
2w
L
L



2w
P
Z
30
(
30
)
S
L
Z
11
)
30
/8k in Equation 28.
 133.33Z


O
 R






)



--------------------------
------- -
8k


---------- -
R8k
S
R
R


8k
S
S
Series


used for resistive
PROGRAMMING
O


NETWORK
C
R
Parallel
Parallel
S
M
has a
= -V
S
(EQ. 22)
(EQ. 23)
(EQ. 24)
(EQ. 26)
(EQ. 27)
(EQ. 30)
(EQ. 28)
(EQ. 29)
(EQ. 25)
, with a
2W
/Z
L
ISL5585
Substitute Equation 30 into Equation 31 and combine terms
where:
V
AUX = Auxiliary input of SLIC. Not used for AC gains.
V
current and the output of the Sense Amplifier.
I
the input receive current and the feedback current.
I
R
R
impedance.
V
V
protection resistors.
Z
Z
4-Wire to 2-Wire Gain
4-wire to 2-wire gain across the ISL5585 is equal to the V
divided by the input voltage V
receive gain is calculated using Equation 32.
Equation 33 expresses the receive gain (V
terms of network impedances. From Equation 21, the value
of R
ISL5585 plus the protection resistors (Z
results in a 4-wire to 2-wire gain equal to R
in EQ. 33.
2-Wire to 4-Wire Gain
The 2-wire to 4-wire gain is equal to V
reference Figure 4.
From Equation 30 with V
Substituting Equation 35 into Equation 34 and simplify.
G
Loop Equation
–
V
E
Loop Equation
V
X
M
V
L
O
E
IN
SA
TR
2W
P
S
TR
G
2W
4-2
2W
= Internal current in the SLIC that is the difference between
G
= The AC metallic current.
= The line impedance.
= A protection resistor (typical 49.9Ω).
= An external resistor/network for matching the line
= The source impedance of the device.
=
= The input voltage at the -IN pinthrough resistor R
S
+
= An internal node voltage that is a function of the loop
= The tip to ring voltage at the output pins of the SLIC.
-I
= The tip to ring voltage including the voltage across the
=
=
was set to match the line impedance (Z
Z
–
M
Z
--------------------------------------
V
----------- - = 2
Z
--------------------
V
V
L
L
2R
2W
I
O
2W
IN
+
M
Z
V
P
Z
L
+
2W
Z
O
Z
-------------------------------------- -
+ V
2R
L
L
+
at Tip/Ring interface



+
2R
P
--------- -
R
TR
R
2R
I
IN
M
S
Z
P
= 0



L
–
P
--------------------------------------- -
Z
V
+
=
L
TR
Z
+
2V
O
IN
Z
=
Z
O
IN
L
= 0
0
+ 2
--------- -
R
R
IN
IN
S
RP
, reference Figure 4. The
=
2
TX
------------------- -
Z
0
L
/E
Z
+ 2R
+
L
IN
S
Z
G
/R
L
to V
with V
L
P
=
IN
) to the
). This
, as shown
--------- -
R
R
2W
IN
S
IN
(EQ. 32)
(EQ. 31)
(EQ. 33)
(EQ. 34)
(EQ. 35)
(EQ. 36)
) in
= 0,
IN
2W
.