SI3200-X-FS SILABS [Silicon Laboratories], SI3200-X-FS Datasheet - Page 31

• Manufacturer Part Number: SI3200-X-FS
• Manufacturer: SILABS [Silicon Laboratories]

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
minimum battery supply required can be calculated with
the following equation:
where V
The default V
overhead for a 3.1 dBm signal into a 600 Ω loop
impedance with an I
setting of 4 mA. A V
headroom to source a maximum I
3.1 dBm audio signal and an ABIAS setting of 16 mA.
For a typical operating condition of V
I
These conditions apply when the dc-sensing inputs
(STIPDCa/b and SRINGDCa/b) are placed on the SLIC
LIM
= 22 mA:
CM
Figure 15. Simplified Dual ProSLIC Linefeed Architecture for TIP and RING Leads
V
and V
OC MAX
,
CM
V
OV
BAT
(Diagram Illustrates either TIP or RING Lead of a Single Channel)
=
value of 3 V provides sufficient
LIM
are provided in Table 8 on page 14.
OV
≥
56 V
V
setting of 22 mA and an ABIAS
value of 4 V provides sufficient
OC
TIP or
RING
–
+
(
3 V
C
V
AC
CM
Control
Audio
+
+
4 V
LOOP
Codec
Audio
V
V
V
V
BATH
BATL
BAT
OV
)
A/D
D/A
=
BAT
Control
R
of 45 mA with a
Audio
Loop
DC
49 V
Audio
Diagnostic
Filters
= –56 V and
Rev. 1.2
DSP
Current
Mirror
Σ
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 "3.14.3. Linefeed Overhead Voltage Considerations
During Ringing" on page 53 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 "3.6. Linefeed Calibration" on page 36 for details.
Low
Frequency
Diagnostic
Filters
Control
Si3200
SLIC DAC
Loop
SLIC
OV
Control
Battery
Select
Monitor A/D
PROT
DC
A/D
D/A
and V
measures dc line voltages on TIP and
Control
SLIC
x I
CM
LIM
AC
must be increased by a voltage
V
where R
R
BAT
couples the ac line voltages on
BAT
Si3220/
Si3225
Sense
PROT
Si3220/25
is the value of each
DC
and R
BAT
31