SI3230 SILABS [Silicon Laboratories], SI3230 Datasheet - Page 18

• Manufacturer Part Number: SI3230
• Manufacturer: SILABS [Silicon Laboratories]

Si3230
2. Functional Description
The Si3230 ProSLIC
device that provides all the SLIC, DTMF detection, and
signal generation functions needed for a complete
analog telephone interface when connected to an
external codec. The ProSLIC performs all battery,
overvoltage, ringing, supervision, and test functions.
Unlike most monolithic SLICs, the Si3230 does not
require
supplies. Instead, it generates all necessary battery
voltages from a positive dc supply using its own dc-dc
converter controller. Two fully programmable tone
generators can produce DTMF tones, phase continuous
FSK (caller ID) signaling, and call progress tones.
DTMF decoding and pulse metering signal generation
are also integrated. The Si3201 linefeed interface IC
performs all high voltage functions. As an option, the
Si3201 can also be replaced with low-cost discrete
components as shown in the typical application circuit in
Figure 6.
The 3230 is primarily meant to be used with Broadcom
devices BCM1101, BCM3351/52, and BCM6352.
Special directions for interfacing and operating the
Si3230 are needed. Please contact Silicon Laboratories
for guidance with other applications.
The linefeed provides programmable on-hook voltage,
programmable off-hook loop current, reverse battery
operation, loop or ground start operation, and on-hook
transmission ringing voltage. Loop current and voltage
are continuously monitored using an integrated A/D
converter. Balanced 5 REN ringing with or without a
programmable dc offset is integrated. The available
offset, frequency, waveshape, and cadence options are
designed to ring the widest variety of terminal devices
and to reduce external controller requirements.
2.1. Linefeed Interface
The ProSLIC’s linefeed interface offers a rich set of
features and programmable flexibility to meet the
broadest applications requirements. The dc linefeed
characteristics are software programmable; key current,
voltage, and power measurements are acquired in
realtime and provided in software registers.
2.1.1. DC Feed Characteristics
The ProSLIC has programmable constant voltage and
constant current zones as depicted in Figure 8. Open
circuit TIP-to-RING voltage (V
voltage zone and is programmable from 0 V to 94.5 V in
1.5 V steps. The loop current limit (I
constant current zone and is programmable from 20 mA
to 41 mA in 3 mA steps. The ProSLIC has an inherent
dc output resistance (R
18
externally
®
supplied
O
is a single low-voltage CMOS
) of 160 Ω.
OC
) defines the constant
high-voltage
LIM
) defines the
Preliminary Rev. 0.96
battery
The TIP-to-RING voltage (V
a programmable voltage (V
headroom to the positive-most terminal (TIP in forward
polarity states and RING in reverse polarity states) for
carrying audio signals. Table 19 summarizes the
parameters to be initialized before entering an active
state.
2.1.2. Linefeed Architecture
The ProSLIC is a low-voltage CMOS device that uses
either an Si3201 linefeed interface IC or low-cost
external components to control the high voltages
required for subscriber line interfaces.
The ProSLIC uses both voltage and current sensing to
control TIP and RING. DC and AC line voltages on TIP
and RING are measured through sense resistors R
and R
transistors Q
isolates the high-voltage base of Q
The ProSLIC measures voltage at various nodes in
Parameter
*Note: The ProSLIC uses registers that are both directly
V
V
V
I
LIM
(TIP-RING )
Figure 8. Simplified DC Current/Voltage
OC
CM
Table 19. Programmable Ranges of DC
AC
and indirectly mapped. A “direct” register is one that
is mapped directly.
, respectively. The ProSLIC uses linefeed
V
Programmable
O C
(V)
20 to 41 mA
P
Linefeed Characteristics
0 to 94.5 V
0 to 94.5 V
Linefeed Characteristic
Range
and Q
R
Constant
Voltage
O
N
Zone
=160
to drive TIP and RING. Q
Default
20 mA
Value
OC
48 V
3 V
Ω
CM
) is offset from ground by
I
LIM
) to provide voltage
N
Constant Current
VCM[5:0]
VOC[5:0]
Register
ILIM[2:0]
from the ProSLIC.
Bits
I
LO O P
Zone
(m A)
Register 71
Register 72
Register 73
Location*
Direct
Direct
Direct
DC
DN