SI3225-KQ Silicon Laboratories Inc, SI3225-KQ Datasheet - Page 54

• Manufacturer Part Number: SI3225-KQ
• Description: IC SLIC/CODEC DUAL-CH 64TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: ProSLIC®r

Specifications of SI3225-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: SLIC
• 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
Oscillator Frequency and Amplitude
Each of the two tone generators contains a two-pole
resonant
frequency and amplitude, which are programmed via
RAM addresses OSC1FREQ, OSC1AMP, OSC1PHAS,
OSC2FREQ, OSC2AMP, and OSC2PHAS. The sample
rate for the two oscillators is 8000 Hz. The equations
are as follows:
where f
where desired Vrms is the amplitude to be generated;
n = 1 or 2 for oscillator 1 or oscillator 2, respectively.
For example, to generate a DTMF digit of 8, the two
required tones are 852 Hz and 1336 Hz. Assuming we
want to generate half-scale values (ignoring twist), the
following values are calculated:
54
OSCnAMP
OSC1FREQ
n
Counter
OSCnTA
Modulo
OSCnTI
16-Bit
is the frequency to be generated;
8 kHz
Clock
n = "1" or "2" for Tone Generator 1 and 2, respectively
oscillator
coeff
OSCnFREQ = coeff
coeff
=
OSCnTIEN
OSCnTAEN
1
-- - 1 coeff
4
1
=
n
=
----------------------- -
1
OSCnPHAS = 0,
0.78434 2
= cos(2 π f
+
–
cos
circuit
coeff
OSCnTA
OSCnTI
OSCnEN
Expire
Expire
*Tone Generator 1 Only


2π852
---------------- -
8000
(
×
(
14
n
2
with
Cross
/8000 Hz),
Logic


)
Zero
15
Logic
Logic
n
=
=
–
INT
INT
x (2
12851
1
0.78434
Figure 35. Tone Generator Diagram
)
ZEROENn
a
×
14
ENSYNCn
DesiredVrms
------------------------------------- -
);
programmable
Zero Cross
=
1.11Vrms
OSnTIS
Logic
Load
OSnTAS
OSnTIE
OSnTAE
0x3233
Preliminary Rev. 0.91
REL*
Register
Enable
Load
Two-Pole
Resonant
Oscillator
The computed values above are written to the
corresponding registers to initialize the oscillators. Once
the oscillators are initialized, the oscillator control
registers can be accessed to enable the oscillators and
direct their outputs.
Tone Generator Cadence Programming
Each of the two tone generators contains two timers,
one for setting the active period and one for setting the
inactive period. The oscillator signal is generated during
the active period and suspended during the inactive
period. Both the active and inactive periods can be
programmed from 0 to 8 seconds in 125 µ s steps. The
active period time interval is set using OSC1TA for tone
generator 1 and OSC2TA for tone generator 2.
8 kHz
Clock
OSC1AMP
OSC2AMP
=
=
OSC2FREQ = 0.49819 (2
0x590
0x942
OSCnFREQ
OSCnPHAS
OSCnAMP
coeff
2
=
= cos (2 π 1336 / 8000) = 0.49819
=
1
-- - 0.21556
4
1
-- - 0.50181
4
-------------------- -
1.78434
-------------------- -
1.49819
OSC1PHAS = 0
OSC2PHAS = 0
Routing
Signal
×
×
(
(
2
2
14
15
15
) = 8162 = 0x1FE2
–
–
ROUTn
1
1
)
)
×
×
0.5
0.5
=
=
to RX Path
to TX Path
1424
2370