SI3220-BQ Silicon Laboratories Inc, SI3220-BQ Datasheet - Page 58

• Manufacturer Part Number: SI3220-BQ
• Description: IC SLIC/CODEC DUAL-CH 64TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: ProSLIC®r

Specifications of SI3220-BQ

• 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: -40°C ~ 85°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: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Number Of Channels: 2
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Si3220/Si3225
The pulse metering oscillator has a volume envelope
(linear ramp) on the on/off transitions of the oscillator.
The ramp is controlled by the value in the PMRAMP
RAM address, and the sinusoidal generator output is
multiplied by this volume before it is sent to the Pulse
Metering DAC. The volume value is incremented by the
value in PMRAMP at an 8 kHz rate. The volume will
ramp from 0 to 7FFF in increments of PMRAMP to allow
58
Pulse Metering Inactive Timer
Pulse Metering Attack/Decay
PMAMPL
Pulse Metering Active Timer
Pulse Metering Frequency
PM Inactive Timer Enable
Pulse Metering Amplitude
PM Active Timer Enable
Pulse Metering, Control
Pulse Metering Enable
PM Waveform Present
Pulse Metering AGC
Amplitude Threshold
Ramp Rate
Parameter
Coefficient
Coefficient
Interrupt
=
Table 34. Register and RAM Locations Used for Pulse Metering Generation
where Full Scale V
1
-- - 1 coeff
4
----------------------- -
1
+
–
coeff
×
(
2
15
–
PK
1
)
= 0.5 V.
×
------------------------------------- -
FullScaleV
IRQVEC1, IRQEN1
PMTALO/PMTAHI
DesiredV
PMTILO/PMTIHI
Register/RAM
Mnemonic
PMAMPTH
PMFREQ
PMRAMP
PMAMPL
PMCON
PMCON
PMCON
PMCON
Preliminary Rev. 0.91
PK
PK
the value of PMRAMP to set the slope of the ramp. The
clip detector stops the ramp once the signal seen at the
transmit path exceeds the amplitude threshold set by
PMAMPTH, which provides an automatic gain control
(AGC) function to prevent the audio signal from clipping.
When the pulse metering signal is turned off, the
volume ramps down to 0 by decrementing according to
the value of PMRAMP. Figure 38 illustrates the
functional blocks involved in pulse metering generation,
and Table 34 presents the register and RAM locations
required that must be set to generate pulse metering
signals.
PMAMPTH[15:0]
PMRAMP[15:0]
PULSETA[15:0]
PMFREQ[15:3]
PMAMPL[15:0]
PULSETI[15:0]
Register/RAM
PULSTAE,
PULSTAS,
PULSTIE,
PULSTIS
ENSYNC
PULSE1
TAEN
TIEN
Bits
Interrupt Status and control
Sets oscillator frequency
Sets oscillator amplitude
Indicates signal present
Description/Range
0 to 8.19 s (125 µ s)
0 to 8.19 s (125 µ s)
(full amplitude)
Enable/disable
Enable/disable
Enable/disable
0 to PMAMPL
0 to 500 mV
(LSB Size)
registers