SI3232-G-FQ Silicon Laboratories Inc, SI3232-G-FQ Datasheet - Page 48

• Manufacturer Part Number: SI3232-G-FQ
• Description: IC SLIC PROG DUAL-CH 64TQFP
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3232-G-FQ

• Function: Subscriber Line Interface Concept (SLIC)
• Interface: ISDN
• Number Of Circuits: 2
• Voltage - Supply: 3.13 V ~ 3.47 V
• Current - Supply: 28mA
• Power (watts): 280mW
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Si3232
4.14. Audio Path Processing
The Si3232 is designed to connect directly to integrated
access device (IAD) chipsets, such as the Broadcom
BCM3341, as well as other standard codecs that use a
differential audio interface. Figure 3 on page 15
illustrates the simplified block diagram for the Si3232.
4.14.1. Transmit Path
In the transmit path, the analog signal fed by the
external ac-coupling capacitors, C1 and C2, is amplified
by the analog transmit amplifier, ATX, prior to the
differential analog output to the A/D converter in the
external codec. The ATX stage can be used to add 3 dB
of attenuation by programming the ATX bit of the
AUDGAIN register. A mute function is also available by
setting the ATXMUTE bit of the AUDGAIN register to 1.
The main role of the ATX stage is to attenuate incoming
signals to best match the input scale of the external A/D
converter to maximize signal-to-noise ratio.
The resulting gain levels using the ATX stage are
summarized in Table 29. All settings assume a 0 dBm0
TIP-RING audio input signal with the audio TX level
measured differentially at VTXPa-VTXNa (for channel
a) or VTXPb-VTXNb (for channel b).
48
I
BUF
Z
A
Figure 25. Pulse Metering Generation Block Diagram
+
Metering
Pulse
DAC
Preliminary Rev. 0.96
Oscillator
Metering
From VRX inputs
Pulse
+
4.14.2. Receive Path
In the receive path, the incoming audio signal from the
D/A converter in the external codec is passed through
an ARX stage where the user can attenuate audio
signals in the analog domain prior to transmission to
TIP/RING. Settings of 0, –3, and –6 dB are available by
programming the ARX[1:0] bits of the AUDGAIN
register to the appropriate settings. A mute function is
also available by setting the ARXMUTE bit of the
AUDGAIN register to 1. When not muted, the resulting
analog
transconductance amplifier, Gm, which drives the off-
chip current buffer, I
ATXMUT
Volume
Setting
8 kHz
Table 29. ATX Attenuation Stage Settings
+
E
1
0
0
signal
Setting
ATX
PMRAMP
X
0
1
Logic
is
7FFF
Clip
or 0
+
–
Peak Detector
BUF
applied
.
Typical TX Path Gain
–1.584 dB (G = 10/12)
–4.682 dB (G = 7/12)
12/16 kHz
Bandpass
Mute (no output)
at
–
the
To VTX outputs
+
input
PMAMPTH
of
the