SI3220-KQ Silicon Laboratories Inc, SI3220-KQ Datasheet - Page 31

• 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

Figure 16. V
For ground start operation, the active lead presents a
640 Ω output impedance during the on-hook state and a
320 Ω output impedance in the off-hook state. The
“open” lead presents a high-impedance feed (>150 k Ω ).
Figure 17 illustrates a typical ground start application
using V
state. The ring ground detection threshold and
debouncing interval are both programmable.
Figure 17. V
–20
–40
–60
OC
0
= 48 V and I
60
50
40
30
20
10
0
V
TIP–RING
Ground Start Operation
R
OC
Loop Start Operation
R O
O
RING
TIP-RING
Constant
Voltage
Region
= 640 Ω
TIP-RING
Constant
10
= 640 Ω
Voltage
Region
10
vs. I
I
vs. I
RING
I
LIM
LOOP
20
RING
20
I
LIM
LOOP
(mA)
= 24 mA in the TIP OPEN
R
O
Loop Closure
(mA)
Characteristic for
Threshold
30
= 320 Ω
R O
Characteristic for
Loop Current
30
Loop Current
I LIM = 24 mA
= 320 Ω
Constant
I
Loop Closure
Constant
Region
LIM
Region
Threshold
40
= 24 mA
40
Preliminary Rev. 0.91
50
50
The Modfeed scheme also allows the user to modify the
apparent VOC voltage as a means of boosting the
linefeed voltage when the battery voltage drops below a
certain level. Figure 18 illustrates a typical Si3225
application using Modfeed while sourcing a 1930 Ω
subscriber loop (1500 Ω loop impedance with a 430 Ω
phone connected) from a 48 V battery. For V
V
to 42 V given a programmed value of 42 V for the VOC
RAM location. When a loop closure event occurs, the
TIP-RING voltage decreases linearly until it reaches a
preset voltage threshold that is lower than VOCTRACK
by an amount programmed into the VOCLTH RAM
location. Exceeding this threshold causes the Si3220/
Si3225 to increase its “target” V
programmed into the VOCDELTA RAM location to
provide additional overhead for driving the higher
impedance loop. In the on-hook condition, the TIP-
RING voltage increases linearly until it rises above a
second preprogrammed voltage threshold, which is
higher than VOCTRACK by an amount programmed
into the VOCHTH RAM location. This offers the ability to
drive very long loop lengths while using the lowest
possible battery voltage. Consult the factory for optimal
register and RAM location settings for specific
applications.
Linefeed Calibration
An internal calibration algorithm corrects for internal and
external component errors. The calibration is initiated by
setting the CAL register bit. This bit automatically resets
on completion of the calibration cycle.
A calibration should be executed following system
powerup. Upon release of the chip reset, the chipset will
be in the Open state and calibration may be initiated.
Figure 18. V
CM
VOCDELTA
V
VOCTRACK
values of 3 V, the VOCTRACK RAM location is set
TIP
–
50
40
30
20
10
0
RING
R
TIP–RING
O
(V)
= 640 Ω
using Modfeed™
Si3220/Si3225
10
vs. I
load line
1930 Ω
LOOP
OC
20
level by an amount
R
Characteristics
O
= 320 Ω
I
LIM
(mA)
OV
and
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