ISL5585 Intersil Corporation, ISL5585 Datasheet - Page 10
ISL5585
Manufacturer Part Number
ISL5585
Description
3.3 Volt Ringing Slic Family For Voice Over Broadband (VOB)
Manufacturer
Intersil Corporation
Datasheet
1.ISL5585.pdf
(22 pages)
The gain of the Transmit Amplifier, set by R
the programmed impedance of the device. The capacitor
C
ground symbols in the model represent AC grounds, not
actual DC potentials.
The Sense Amplifier is configured as a 4 input differential
amplifier with a gain of 3/4. The voltage at the output of the
sense amplifier (V
V
resulting from V2 and so on (reference Figure 4).
Where ∆V is equal to I
V
V
V
V
V
V
FB
SA
SA
SA
SA
SA
SA
SA
1 is the voltage resulting from V1, V
1
2
3
4
blocks the DC component of the loop current. The
=
=
=
=
=
=
[
2
(
–
3
-- - V
4
–
3
-- - V
4
(
V
∆
3
-- - V
4
3
-- - V
4
(
(
2
I
(
(
M
–
2
4
V
1
3
×
)
)
V
+
-
2W
)
)
1
20
)
+
)
SA
3
-- -
4
I
+
(
-
M
E
-
V
G
=
RING
) is calculated using superposition.
4
TIP
Z
–
M
∆
L
I
V
R
M
3
SENSE
30
-
+
)
]
V
R
R
3
-- -
4
I
I
M
TR
M
10
P
P
=
+
-
+
-
[
(R
∆
Z
V
0
V
SENSE
+
2
V
3
∆
-
V
R
R
+
SA
SENSE
SENSE
20Ω
]
I
20Ω
FIGURE 4. AC SIGNAL TRANSMISSION MODEL
I
M
3
-- -
4
M
2 is the voltage
= 20Ω)
S
+
-
, determines
V
4
-
V
1
AMPLIFIER
AMPLIFIER
FEED
FEED
I
R
+
X
I
+
R
(EQ. 11)
(EQ. 12)
(EQ. 14)
(EQ. 15)
(EQ. 16)
X
(EQ. 13)
4R
4R
4R
4R
+
+
-
-
-
INTERSIL
ISL5585
ISL5585
I
FEEDBACK
AMPLIFIER
X
3R
+
-
3R
RECEIVE BLOCK
The voltage at VTX is equal to:
V
Setting V
and substituting it into EQ18 will enable the user to
determine the required feedback to match the line
impedance at V
2-Wire Impedance Matching
Z
Z
resistor. R
V
V
1:1
V
Z
Z
R
O
L
TR
SA
TX
O
O
TR
S
is the line impedance and R
is the source impedance of the device and is defined as.
= ∆I
SENSE
AMPLIFIER
=
=
=
is defined in Figure 4, note polarity assigned to V
=
=
----------------- - R
133.33
Z
133.33 Z
8k
TA
M
–
2 V
L
V
30
IN
(
1
–
I
IN
S
X
2R
TX
equal to zero in EQ 18, defining Z
is defined as:
--------- -
R
(
R
R
P
)
IN
S
R
S
L
=
2W
–
–
2 V
2R
V
as shown in Equation 19.
AUX
V
V
SA
P
TX
TX
IN
+
-IN
)
-
VFB
R
C
R
------- -
8k
S
FB
--------- -
R
R
S
IN
S
=
+
–
∆ (
P
V
I
is the external protection
IN
M
R
30
IN
--------- -
R
R
IN
)
S
FROM CODEC
R
------- -
8k
–
S
∆ (
V
I
IN
M
O
30
= -V
)
R
------- -
8k
S
(EQ. 18)
TR
(EQ. 19)
(EQ. 20)
(EQ. 21)
(EQ. 17)
TR
/∆I
:
M