SI3220-KQ Silicon Laboratories Inc, SI3220-KQ Datasheet - Page 36

• 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

Si3220/Si3225
provided in Table 21. The primary input to the system is
the loop current sense value from the voltage/current/
power monitoring circuitry and reported in the ILOOP
RAM address. The LCS value is processed in the input
signal processor (ISP) provided the LFS bits in the
Linefeed register indicate the device is in an Active or
On-Hook Transmission state. The output of the ISP is
the input to a programmable digital low pass filter, which
removes unwanted ac signal components before
threshold detection.
The low-pass filter coefficient is calculated using the
equation below and is entered into the LCRLPF RAM
location.
LCRLPF = [(2 π f x 4096)/800]
Where f = the desired cutoff frequency of the filter.
The programmable range of the filter is from 0 (blocks
all signals) to 4000 (unfiltered). A typical value of 10 Hz
(0A10h) is sufficient to filter out any unwanted ac
36
Loop Closure Interrupt Pend-
ing
Loop Closure Interrupt Enable
Linefeed Shadow
Loop Closure Detect Status
Loop Closure Detect
Debounce Interval
Loop Current Sense
ILOOP
Parameter
Processor
Table 21. Register and RAM Locations Used for Loop Closure Detection
Signal
Input
LFS
Figure 20. Discrete Linefeed Circuit for Power Monitoring
LCRLPF
Register/RAM
Digital
LPF
Mnemonic
LINEFEED
IRQVEC2
LCRRTP
IRQEN2
LCRDBI
ILOOP
LCROFFHK
Loop Closure
Threshold
Preliminary Rev. 0.91
LCRONHK
+
–
Register/RAM
LCRDBI[15:0]
ILOOP[15:0]
LFS[2:0]
LOOPS
LOOPE
LCR
Bits
artifacts while allowing the dc information to pass
through the filter.
The output of the low pass filter is compared to a
programmable threshold, LCROFFHK. Hysteresis is
enabled
LCRONHK, to detect the loop going to an open or on-
hook state. The threshold comparator output feeds a
programmable debounce filter. The output of the
debounce filter remains in its present state unless the
input remains in the opposite state for the entire period
of time programmed by the Loop closure debounce
interval, LCRDBI. There is also a loop closure mask
interval (LCRMASK) that is used to mask transients
caused when an internal ringing burst (with no offset)
ends in the presence of a high REN load. If the
debounce interval has been satisfied, the LCR bit is set
to indicate that a valid loop closure has occurred.
LCRMASK
Closure
Loop
Mask
by
Programmable
Monitor only
Monitor only
0 to 40.96 s
Debounce
101.09 mA
programming
LCRDBI
50.54 to
Filter
Yes/No
Yes/No
Range
3.097 µ A
a
1.25 ms
LCR
Interrupt
LOOPE
LSB
Size
Logic
N/A
N/A
N/A
N/A
second
Resolution
Effective
1.25 ms
500 µ A
threshold,
N/A
N/A
N/A
N/A
LOOPS
1