SI3220-KQ Silicon Laboratories Inc, SI3220-KQ Datasheet - Page 27

• Manufacturer Part Number: SI3220-KQ
• Description: IC SLIC/CODEC DUAL-CH 64TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: ProSLIC®r

Specifications of SI3220-KQ

• Package / Case: *
• Function: Subscriber Line Interface Concept (SLIC), CODEC
• Interface: GCI, PCM, SPI
• Number Of Circuits: 2
• Voltage - Supply: 3.3V, 5V
• Current - Supply: 65mA
• Power (watts): 941mW
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Includes: Battery Switching, BORSCHT Functions, DTMF Generation and Decoding, FSK Tone Generation, Modem and Fax Tone Detection
• Product: Telecom
• Supply Voltage (min): 3.13 V
• Supply Current: 22 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

DC Feed Characteristics
The Si3220 and Si3225 offer programmable constant
voltage and constant current operating regions as
illustrated in Figure 14 and Figure 16. The constant
voltage region (defined by the open-circuit voltage, V
is programmable from 0 to 63.3 V in 1 V steps. The
constant current region (defined by the loop current
limit, I
0.87 mA steps. The Si3220 and Si3225 exhibit a
characteristic dc impedance of 320 Ω during Active
mode.
The TIP-RING voltage (V
programmable voltage (V
voltage headroom to the most positive terminal
(typically the TIP lead in normal polarity or the RING
lead in reverse polarity) for carrying audio signals. A
similar programmable voltage (V
between the most negative terminal and the battery
supply rail for carrying audio signals. (See Figure 14.)
The user-supplied battery voltage must have sufficient
amplitude under all operating states to ensure sufficient
headroom. The Si3200 may be powered by a lower
secondary battery supply (V
dissipation when driving short-loop lengths.
Calculating Overhead Voltages
The two programmable overhead voltages (V
V
V
operating conditions, these overhead voltages are
sufficiently low enough to maintain the desired TIP-
RING voltage (V
conditions under which the user must exercise care in
providing a battery supply with enough amplitude to
supply the required TIP-RING voltage and enough
margin to accommodate these overhead voltages. The
V
condition. Therefore, the open-circuit voltage (V
CM
BAT
CM
Figure 14. DC Linefeed Overhead Voltages
) represent one portion of the total voltage between
and ground as illustrated in Figure 14. In normal
voltage is programmed for a given operating
LIM
V
) is programmable from 18 to 45 mA in
Constant I Region
Secondary V
V
BATL
Selected
V
OV
(Forward State)
BAT
OC
). However, there are certain
V
CM
OC
Constant V Region
CM
) is offset from ground by a
BATL
V
) to provide sufficient
OV
) to reduce total power
V
OC
OV
V
V
V
RING
) is an offset
BATH
TIP
R
LOOP
Preliminary Rev. 0.91
OV
and
OC
OC
)
)
varies according to the required overhead voltage (V
and the supplied battery voltage (V
should pay 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 is provided. Because 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
then determine the maximum loop impedance that can
be driven based on the battery supply provided. The
minimum battery supply required can be calculated with
the following equation:
where V
V
3.1 dBm signal into a 600 Ω loop impedance with an
I
V
a maximum I
and an ABIAS setting of 16 mA. For a typical operating
condition of 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 also
apply.
See the "Linefeed Overhead Voltage Considerations
During Ringing" on page 43 for details on calculating the
overhead voltage during the ringing state.
The Dual ProSLIC chipset uses both voltage and
current information to control TIP and RING. Sense
resistor R
RING; Capacitor C
the TIP and RING leads to be measured. The Si3220
and Si3225 both use the Si3200 to drive TIP and RING
and isolate the high-voltage line from the low-voltage
CMOS devices.
The Si3220 and Si3225 measure voltage at various
nodes to monitor the linefeed current. R
provide these measuring points. The sense circuitry is
calibrated on-chip to guarantee measurement accuracy.
See "Linefeed Calibration" on page 31 for details.
LIM
CM
OV
setting of 22 mA and an ABIAS setting of 4 mA. A
value of 4 V provides sufficient headroom to source
value of 3 V provides sufficient overhead for a
OV
CM
V
PROT
DC
and V
and V
OC MAX
LOOP
BAT
,
measures dc line voltages on TIP and
x I
V
OV
CM
BAT
= –56 V and I
LIM
of 45 mA with a 3.1 dBm audio signal
AC
=
are provided in Table 8. The default
≥
must be increased by a voltage
56 V
where R
couples the ac line voltages on
V
Si3220/Si3225
OC
–
+
(
3 V
V
PROT
CM
LIM
+
+
4 V
= 22 mA:
V
is the value of each
OV
)
=
OV
BAT
49 V
DC
and V
). The user
OC
and R
must be
CM
that
OV
BAT
27
)