HC5513BIM Intersil, HC5513BIM Datasheet - Page 8

• Manufacturer Part Number: HC5513BIM
• Description: IC SLIC DLC/FLC LP STDBY 22-DIP
• Manufacturer: Intersil
• Series: UniSLIC14r

Specifications of HC5513BIM

• Function: Subscriber Line Interface Concept (SLIC)
• Number Of Circuits: 1
• Current - Supply: 2.25mA
• Power (watts): 1.5W
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 22-DIP (0.400", 10.16mm)
• Includes: Ground Key Detector, Programmable Loop Current Detector, Ring Trip Detector, Thermal Shutdown
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Supply: -
• Interface: -

The HC5513 is a current feed voltage sense Subscriber Line
Interface Circuit (SLIC). This means that for short loop
applications the SLIC provides a programed constant current to
the tip and ring terminals while sensing the tip to ring voltage.
The following discussion separates the SLIC’s operation into
its DC and AC path, then follows up with additional circuit
and design information.
Constant Loop Current (DC) Path
SLIC in the Active Mode
The DC path establishes a constant loop current that flows
out of tip and into the ring terminal. The loop current is
programmed by resistors R
the R
the voltage across R
constant current feed conditions, the voltage drop across R
sets the R
flows through R
establishes a current (I
+R
current circuit, to become the tip and ring loop currents.
For the purpose of the following discussion, the saturation
guard voltage is defined as the maximum tip to ring voltage
at which the SLIC can provide a constant current for a given
battery and overhead voltage.
For loop resistances that result in a tip to ring voltage less than
the saturation guard voltage the loop current is defined as:
where: I
R
Capacitor C
signals from the battery feed control loop. The value of C
is determined by Equation 2:
where T = 30ms.
NOTE: The minimum C
Figure 14 illustrates the relationship between the tip to ring
voltage and the loop resistance. For a 0Ω loop resistance both
tip and ring are at V
so does the voltage differential between tip and ring. When
this differential voltage becomes equal to the saturation guard
voltage, the operation of the SLIC’s loop feed changes from a
constant current feed to a resistive feed. The loop current in
the resistive feed region is no longer constant but varies as a
function of the loop resistance.
I
C
L
DC1
DC
=
DC2
------------------------------------- -
R
DC
=
and R
DC1
). This current is then multiplied by 1000, in the loop
T
L
pin (Figure 13). The R
2.5V
×
= Constant loop current.
DC
+


DC
---------------
R
DC2
R
DC1
voltage to -2.5V. This occurs when current
DC2
1
1
between R
= Loop current programming resistors.
into the current source I
+
×
BAT
---------------
R
1000
1
Circuit Operation and Design Information
DC2
DC
1
in the saturation guard circuit. Under
RSN
/2. As the loop resistance increases,
value is obtained if R


DC1
) that is equal to V
DC1
8
and R
DC
, R
DC2
voltage is determined by
DC2
and the voltage on
2
removes the VF
. The R
DC1
RDC
= R
DC
/(R
DC2
voltage
DC1
(EQ. 1)
(EQ. 2)
.
DC
1
HC5513
Figure 15 shows the relationship between the saturation
guard voltage, the loop current and the loop resistance. Notice
from Figure 15 that for a loop resistance <1.2kΩ (R
21.4k
region and for resistances >1.2kΩ the SLIC is operating in the
resistive feed region. Operation in the resistive feed region
allows long loop and off-hook transmission by keeping the tip
and ring voltages off the rails. Operation in this region is
transparent to the customer.
The Saturation Guard circuit (Figure 13) monitors the tip to
ring voltage via the transconductance amplifier A
generates a current that is proportional to the tip to ring
voltage difference. I
until the tip to ring voltage exceeds 12.5V. When the tip to ring
voltage exceeds 12.5V (with no R
more current than I
amplifies its input current by a factor of 12 and the current
through R
current from A
across R
decreases. This results in a corresponding decrease in the
loop current. The R
saturation guard reference voltage beyond 12.5V. Equation 3
R
R
L
L
50
40
30
20
10
-10
-20
-30
-40
-50
0
Ω
0
0
100kΩ
100kΩ
0
) the SLIC is operating in the constant current feed
RESISTIVE FEED
1
CONSTANT CURRENT
1
GUARD VOLTAGE
GUARD VOLTAGE
decreases and the output voltage on R
becomes the difference between I
V
V
REGION
BAT
BAT
FEED REGION
2
SATURATION
SATURATION
. As the current from A
10
FIGURE 15. V
= -48V, R
= -24V, R
4kΩ
1.5kΩ
LOOP CURRENT (mA)
1
SG
1
FIGURE 14. V
can sink. When this happens A
is internally set to sink all of A
LOOP RESISTANCE (Ω)
pin provides the ability to increase the
SG
SG
V
BAT
20
= 21.4kΩ
=
2kΩ
700Ω
∞
= -48V, I
1.2K
TR
vs I
TR
SG
L
RESISTIVE FEED
L
vs R
resistor) A
= 23mA, R
30
2
AND R
<1.2kΩ
<400Ω
increases, the voltage
REGION
L
CONSTANT CURRENT
FEED REGION
SATURATION GUARD
VOLTAGE, V
SATURATION GUARD
VOLTAGE, V
L
2
SG
and the output
R
R
1
RSG
RSG
1
= 21.4kΩ
supplies
DC
. A
SG
1
’s current
2
= 21.4kΩ
=
1
TR
TR
∞
=
∞
= 38V
= 13V
Ω
V
V
TIP
RING