SI3201-KS Silicon Laboratories Inc, SI3201-KS Datasheet - Page 50

• Manufacturer Part Number: SI3201-KS
• Description: IC LINEFEED INTRFC SI321X 16SOIC
• Manufacturer: Silicon Laboratories Inc
• Series: ProSLIC®r

Specifications of SI3201-KS

• Package / Case: 16-SOIC (3.9mm Width) Exposed Pad, 16-eSOIC, 16-HSOIC
• Function: CODEC
• Interface: PCM, Serial, SPI
• Number Of Circuits: 1
• Voltage - Supply: 3.13 V ~ 5.25 V
• Current - Supply: 88mA
• Power (watts): 800mW
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Includes: BORSCHT Functions, Ring Trip Detection
• Product: SLIC
• Supply Voltage (min): 3.13 V
• Supply Current: 88 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Si3210/Si3211
2.7.2. Receive Path
In the receive path, the optionally-compressed 8-bit
data is first expanded to 16-bit words. The PCMF
register bit can bypass the expansion process, in
which case two 8-bit words are assembled into one 16-
bit word. DACG is the receive path programmable gain
amplifier, which can be programmed from – dB to
6 dB. An 8 kHz, 16-bit signal is then provided to a D/A
converter. The resulting analog signal is amplified by
the analog receive amplifier, ARX, which is user-
selectable to one of several options: mute, –3.5, 0, or
3.5 dB. It is then applied at the input of the
transconductance amplifier (Gm), which drives the off-
chip current buffer (I
2.7.3. Audio Characteristics
The dominant source of distortion and noise in both the
transmit and receive paths is the quantization noise
introduced by the µ-law or the A-law compression
process. Figure 1 on page 7 specifies the minimum
signal-to-noise-and-distortion ratio for either path for a
sine wave input of 200 Hz to 3400 Hz.
Both the µ-law and the A-law speech encoding allow the
audio codec to transfer and process audio signals larger
than 0 dBm0 without clipping. The maximum PCM code
is generated for a µ-law encoded sine wave of
3.17 dBm0 or an A-law encoded sine wave of
3.14 dBm0. The ProSLIC overload clipping limits are
driven by the PCM encoding process. Figure 2 on page
7 shows the acceptable limits for the analog-to-analog
fundamental power transfer-function, which bounds the
behavior of ProSLIC.
The transmit path gain distortion versus frequency is
shown in Figure 3 on page 8. The same figure also
presents the minimum required attenuation for any out-
of-band analog signal that may be applied on the line.
Note the presence of a high-pass filter transfer function
that ensures at least 30 dB of attenuation for signals
below 65 Hz. The low-pass filter transfer function that
attenuates signals above 3.4 kHz has to exceed the
requirements specified by the equations in Figure 3 on
page 8 and is implemented as part of the A-to-D
converter.
The receive path transfer function requirement, shown
in Figure 4 on page 9, is very similar to the transmit path
transfer function. The most notable difference is the
absence of the high-pass filter portion. The only other
differences are the maximum 2 dB of attenuation at
200 Hz (as opposed to 3 dB for the transmit path) and
the 28 dB of attenuation for any frequency above
4.6 kHz. The PCM data rate is 8 kHz and, thus, no
frequencies greater than 4 kHz can be digitally encoded
in the data stream.
50
BUF
).
Rev. 1.45
From this point of view, at frequencies greater than
4 kHz, the plot in Figure 4 should be interpreted as the
maximum allowable magnitude of any spurious signals
that are generated when a PCM data stream
representing a sine wave signal in the range of 300 Hz
to 3.4 kHz at a level of 0 dBm0 is applied at the digital
input.
The group delay distortion in either path is limited to no
more than the levels indicated in Figure 5 on page 10.
The reference in Figure 5 is the smallest group delay for
a sine wave in the range of 500 Hz to 2500 Hz at
0 dBm0.
The block diagram for the voice-band signal processing
paths is shown in Figure 25. Both the receive and
transmit paths employ the optimal combination of
analog and digital signal processing to provide
maximum performance while offering sufficient flexibility
to allow users to optimize for their particular ProSLIC
application. All programmable signal-processing blocks
are indicated symbolically in Figure 25 by a dashed
arrow across them. The two-wire (TIP/RING) voice-
band interface to the ProSLIC is implemented using a
small number of external components. The receive path
interface consists of a unity-gain current buffer, I
while the transmit path interface is simply an ac
coupling capacitor. Signal paths, although implemented
differentially, are shown as single-ended for simplicity.
2.7.4. Transhybrid Balance
The ProSLIC provides programmable transhybrid
balance with gain block H. (See Figure 25.) In the ideal
case, where the synthesized SLIC impedance exactly
matches
transhybrid balance should be set to subtract a –6 dB
level from the transmit path signal. The transhybrid
balance gain can be adjusted from –2.77 dB to
+4.08 dB around the ideal setting of –6 dB by
programming the HYBA[2:0] bits of the Hybrid Control
register (direct Register 11). Note that adjusting any of
the analog or digital gain blocks will not require any
modification of the transhybrid balance gain block, as
the transhybrid gain is subtracted from the transmit path
signal prior to any gain adjustment stages. If desired,
the transhybrid balance can also be disabled using the
appropriate register setting.
2.7.5. Loopback Testing
Four loopback test options are available in the ProSLIC:

The full analog loopback (ALM2) tests almost all the
circuitry of both the transmit and receive paths. The
compressed 8-bit word transmit data stream is fed
back serially to the input of the receive path
expander. (See Figure 25.) The signal path starts
with the analog signal at the input of the transmit
the
subscriber
loop
impedance,
BUF
the
,