HC5513_03 INTERSIL [Intersil Corporation], HC5513_03 Datasheet - Page 9

• Manufacturer Part Number: HC5513_03
• Description: TR909 DLC/FLC SLIC with Low Power Standby
• Manufacturer: INTERSIL [Intersil Corporation]

gives the relationship between the R
programmable saturation guard reference voltage:
where:
V
R
When the Saturation guard reference voltage is exceeded,
the tip to ring voltage is calculated using Equation 4:
where:
V
R
For on-hook transmission R
V
The value of R
loop length operation. This requires that the saturation guard
reference voltage be set as high as possible without clipping
the incoming or outgoing VF signal. A voltage margin of -4V
on tip and -4V on ring, for a total of -8V margin, is
recommended as a general guideline. The value of R
calculated using Equation 6:
where:
V
V
overload level of 3.1V
For on-hook transmission, R
R
SLIC in the Standby Mode
Overall system power is saved by configuring the SLIC in the
standby state when not in use. In the standby state the tip and
ring amplifiers are disabled and internal resistors are connected
between tip to ground and ring to V
enables a loop current to flow when the phone goes off-hook.
The loop current detector then detects this current and the SLIC
is configured in the active mode for voice transmission. The
loop current in standby state is calculated as follows:
V
V
I
R
L
TR
SGREF
SG
TR
L
BAT
MARGIN
SG
SGREF
TR
SG
≈
= Loop resistance.
------------------------------- -
R
V
= Voltage differential between tip and ring.
=
=
= Saturation Guard programming resistor.
=
=
L
= Battery voltage.
BAT
16.66
------------------------------------------------------------------------------------------------------------------------------------------------- -
(
+
R
----------------------------------------------------------------------------
V
V
1800Ω
L
= Saturation Guard reference voltage.
=
BAT
BAT
= Recommended value of -8V to allow a maximum
×
–
12.5
----------------------------------------------------------------------
R
3V
+
L
–
16.66
5 10
------------------
–
SG
+
R
V
+
•
V
(
SG
MARGIN
5 10
R
MARGIN
5 10
------------------
should be calculated to allow maximum
R
•
DC1
•
5
+
SG
5 10
PEAK
5
5
•
+
R
–
)
DC2
×
16.66V
5
.
L



⁄
L
5 10
1
R
= ∞, Equation 4 reduces to:
9
•
= ∞, Equation 6 reduces to:
) 600
+
SG
⁄
(
------------------------------------------
R
BAT
5
DC1
SG
600R
. This connection
resistor value and the
+
R
L
DC2
)



–
16.66V
SG
(EQ. 3)
(EQ. 4)
(EQ. 5)
(EQ. 6)
(EQ. 7)
(EQ. 8)
is
HC5513
where:
I
R
V
(AC) Transmission Path
SLIC in the Active Mode
Figure 16 shows a simplified AC transmission model. Circuit
analysis yields the following design equations:
where:
V
including the voltage drop across the fuse resistors R
V
referenced 4-wire side or the SLIC tip and ring terminals.
I
R
Z
V
Z
E
Z
(AC) 2-Wire Impedance
The AC 2-wire impedance (Z
into the SLIC, including the fuse resistors, and is calculated
as follows:
Let V
Z
Substituting in Equation 9 for V
V
V
---------- -
V
V
Z
L
M
Z
T
RX
L
TR
BAT
TR
TX
RX
G
L
TR
TR
F
TX
TR
TR
TX
= Loop current in the standby state.
T
= Is the AC metallic current.
= Is the line impedance.
= Is used to set the SLIC’s 2-wire impedance.
= Loop resistance.
= Is a fuse resistor.
= Is the AC open circuit voltage.
+
= Is the AC metallic voltage. Either at the ground
is defined as:
= Is the AC metallic voltage between tip and ring,
= Is the analog ground referenced receive signal.
= Is used to set the 4-wire to 2-wire gain.
=
=
=
=
=
RX
= Battery voltage.
V
-----------
Z
Z
V
E
V
---------- -
V
---------- -
RX
RX
I
I
T
TR
TX
TX
G
= 0. Then from Equation 10
M
M
•
–
=
+
------------ -
1000
+
I
M
I
I
2R
---------------------- -
M
------------ -
1000
M
I
•
M
•
Z
F
I
M
2R
L
•
I
M
F
TR
TR
) is the impedance looking
(EQ. 10)
(EQ. 11)
(EQ. 12)
(EQ. 13
(EQ. 14)
F
(EQ. 9)
.