SI3232-KQ Silicon Laboratories Inc, SI3232-KQ Datasheet - Page 21

• Manufacturer Part Number: SI3232-KQ
• Description: IC SLIC PROG DUAL-CH 64TQFP
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3232-KQ

• Package / Case: *
• Function: Subscriber Line Interface Concept (SLIC)
• Interface: ISDN
• Number Of Circuits: 2
• Voltage - Supply: 3.13 V ~ 3.47 V
• Current - Supply: 28mA
• Power (watts): 280mW
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Product: SLIC
• Supply Voltage (min): 3.13 V
• Supply Current: 28 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Number Of Channels: 2
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Calculating Overhead Voltages
The two programmable overhead voltages, V
V
V
operating conditions, these overhead voltages are
sufficiently low to maintain the desired TIP-RING
voltage, V
under which the user must exercise care in providing a
battery supply with enough amplitude to supply the
required TIP-RING voltage as well as enough margin to
accommodate these overhead voltages. The V
voltage is programmed for a given operating condition.
Therefore,
according to the required overhead voltage, V
the supplied battery voltage, V
special attention to the maximum V
might be required for each operating state.
In the off-hook active state, sufficient V
maintained to correctly power the phone from the
battery supply that has been provided. Since the battery
supply depends on the state of the input supply (i.e.,
charging, discharging, or battery backup mode), the
user must decide how much loop current is required and
determine the maximum loop impedance that can be
driven based on the battery supply provided. The
V
CM
BAT
Figure 7. DC Linefeed Overhead Voltages
, represent one portion of the total voltage between
Secondary V
Constant I Region
V
and ground as illustrated in Figure 7. In normal
BATL
Selected
OC
V
the open-circuit
OV
. There are, however, certain conditions
BAT
(Forward State)
V
CM
Constant V Region
Loop Closure Threshold
V
BAT
OV
voltage, V
. The user should pay
V
OV
OC
and V
OC
V
V
V
OC
TIP
RING
BATH
R
, varies
Preliminary Rev. 0.95
must be
LOOP
OV
OV
CM
, and
and
that
CM
minimum battery supply required can be calculated
according to the following equation.
V
The default V
overhead for a 3.1 dBm signal into a 600 Ω loop
impedance.
A V
source a maximum I
3.1 dBm audio signal and an ABIAS setting of 16 mA.
For a typical operating condition, V
I
V
These conditions apply when the dc-sensing inputs,
STIPDCa/b and SRINGDCa/b, are placed on the SLIC
side of any protection resistance placed in series with
the TIP and RING leads. If line-side sensing is desired,
both V
equal to R
protection resistor. Other safety precautions may apply.
See "Linefeed Overhead Voltage Considerations During
Ringing" on page 38 for details on calculating the
overhead voltage during the ringing state.
The Si3232 uses both voltage and current information to
control TIP and RING. Sense resistor R
Figure 6) measures dc line voltages on TIP and RING;
capacitor C
and RING leads to be measured. The Si3232 uses the
Si3200 linefeed interface IC to drive TIP and RING and
to isolate the high-voltage line from the low-voltage
Si3232.
The Si3232 measures voltage at various nodes to
monitor the linefeed current. R
these measuring points. The sense circuitry is
calibrated on-chip to ensure measurement accuracy.
See "Linefeed Calibration" on page 25 for details.
LIM
CM
OC,MAX
OV
= 22 mA:
and V
OV
value of 4 V provides sufficient headroom to
= 56 V – (3 V + 4 V) = 49 V
PROT
OV
and V
AC
are provided in Table 8.
couples the ac line voltages on the TIP
CM
x I
V
CM
BAT
LIM
value of 3 V provides sufficient
≥
must be increased by a voltage
where R
V
LOOP
OC
+
V
of 45 mA along with a
PROT
CM
DC
+
V
is the value of each
OV
and R
BAT
Si3232
= –56 V and
BAT
DC
provide
(see
21