ISL5586 Intersil Corporation, ISL5586 Datasheet - Page 15

• Manufacturer Part Number: ISL5586
• Description: Low Power Ringing SLIC
• Manufacturer: Intersil Corporation

Note that in Figure 13, V
protection resistors.
On the 2-wire side, solving for IL in terms of V
Equation 49. Equations 50 and 51 show the relationship of
V
Feedback Amplifier (V
Simplifying Equation 51 in terms of Z
equation.
The resulting differential output voltage V
Equation 53.
Note that the gain from V
the impedance synthesis loop and will have no effect on the
SLIC’s programmed impedance.
Substituting Equation 53 into Equation 52 and rearranging
terms gives the gain from the 2-wire source (V
differential output of the Transmit Amplifier.
V
V
V
IL
V
V
------------------- -
IN
SA
Z0
Z0
TX4W
TX4W
V
=
I N
to the outputs of the Sense Amplifier (V
=
=



=
------------------------------------- -
Z
–
–
–
L
=









=
+
------------------------------------- -
Z
------------------------------------- -
Z
------------------------------------- -
Z
–
L
L
Z
L
V
V



+
+
0
+
------------------------------------- -
Z
IN
TXP
+
Z
Z
L
Z
V
V
V
0
0
2R
+
0
IN
IN
IN
+
+
+
–
Z
Z
P
2R
2R
0
V
2R
0



TXM
+
P
P
P
2R









Z0
×
×
×
TR
=
P
Z0
2
Z
----- -



) respectively.
2
2
V
0
×
is referenced on the line side of the
×
V
Z0
to the differential output is outside
4-15
20
2W
20
+
-
–
×
×
– (
 
 
FIGURE 12. SCHEMATIC FOR 4-WIRE TO 2-WIRE GAIN DERIVATION
 
-- -  
Z
V
3
-- -
4
R
3
4
R
L
Z0
P
P
0
×
I
gives the following
)
L
----------- -
8KΩ
=
RING
R
TIP
S
V
2V
tr
TX4W
Z0
SA
IN
) and the
IN
, is shown in
20
20
gives
) to the
(EQ. 49)
(EQ. 50)
(EQ. 51)
(EQ. 53)
(EQ. 54)
(EQ. 52)
200K
200K
+
+
-
-
4R
4R
4R
4R
+
-
3R
1:1
3R
If the combination of the protection resistors and the
programmed impedance of the SLIC are equal to Z
voltage V
defined by Equation 55.
4-WIRE TO 4-WIRE GAIN
The 4-Wire to 4-Wire gain is defined in Equation 56 and is
illustrated in Figure 14.The first term is identical to
Equation 48.
The second term is derived in a similar manner as the 2-wire
to 4-wire gain starting with Equation 57.
Moving around the loop from the 2-wire side to the 4-wire
output we solve for V
The relationship between V
shown in Equation 53. Substituting Equation 59 into
Equation 53 yields Equation 60, the second term in Equation
56.
V
V
V
V
------------------- -
------------------- -
V
V
------------------- -
V
V
V
V
2W
SA
Z0
Irx4w
TX4W
TX4W
R X4W
TX4W
T
SA
2W
A
TR
=
=
=
8K
200K
200K
V
----------- -
=
I – L
IL
Z
=
Iz0
=
2W
TR
R
L
–
×
Z
----- -
Z
S



------------------- -
V
×
V
------------------------------------- -
Z
Z
0
L
V
×
RX4W
2
ZO
will be 1/2 V
L
L
2W


-IN
V
×
C
+
------------
8KΩ
FB
R
FB
20
Z
2Z
S
1.4R
0
V
×
×
RXP
0
+


V
------------------- -
SA
3
-- -
4
R
×
2R
V
TX4W
=
V
40
2W
V
RX4W
P
and V
V
----------- -
RX



Z
IN
×
2W
L
3
-- -
4
. The 2-wire to 4-wire gain is
V
Z0
R
RXM
×
=
ZO
1.4R
40
and the 4-wire output is
V
----------- -
Z
.
2W
×
L
3
-- -
4
×
Z
------
2
0
L
(EQ. 55)
(EQ. 57)
(EQ. 58)
(EQ. 59)
(EQ. 60)
the
(EQ. 56)