SI3011-F-FS Silicon Laboratories Inc, SI3011-F-FS Datasheet - Page 33

• Manufacturer Part Number: SI3011-F-FS
• Description: IC VOICE DAA GCI/PCM/SPI 16SOIC
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3011-F-FS

• Includes: Line Voltage Monitor, Loop Current Monitor, Overload Detection, Parallel Handset Detection, Polarity Reversal Detection, TIP and
• Function: Data Access Arrangement (DAA)
• Interface: PCM, Serial, SPI
• Number Of Circuits: 1
• Voltage - Supply: 3 V ~ 3.6 V
• Current - Supply: 8.5mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power (watts): -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

5.18. Ring Detection
The ring signal is resistively coupled from TIP and RING
to the RNG1 and RNG2 pins. The Si3050 supports
either full- or half-wave ring detection. With full-wave
ring detection, the designer can detect a polarity
reversal of the ring signal. See “5.25.Caller ID” on
page 36. The ring detection threshold is programmable
with the RT bit (Register 16, bit 0) and RT2 bit
(Register 17, bit 4). The ring detector output can be
monitored in three ways. The first method uses the
RGDT pin. The second method uses the register bits,
RDTP, RDTN, and RDT (Register 5). The final method
uses the DTX output.
The ring detector mode is controlled by the RFWE bit
(Register 18, bit 1). When the RFWE bit is 0 (default
mode), the ring detector operates in half-wave rectifier
mode. In this mode, only positive ring signals are
detected. A positive ring signal is defined as a voltage
greater than the ring threshold across RNG1-RNG2.
Conversely, a negative ring signal is defined as a
voltage less than the negative ring threshold across
RNG1-RNG2. When the RFWE bit is 1, the ring detector
operates in full-wave rectifier mode. In this mode, both
positive and negative ring signals are detected.
The first method to monitor ring detection output uses
the RGDT pin. When the RGDT pin is used, it defaults
to active low, but can be changed to active high by
setting the RPOL bit (Register 14, bit 1). This pin is an
open-drain output, and requires a 4.7 k  pullup or
pulldown for correct operation. If multiple RGDT pins
are connected to a single input, the combined pullup or
pulldown resistance should equal 4.7 k 
When the RFWE bit is 0, the RGDT pin is asserted
when the ring signal is positive, which results in an
output signal frequency equal to the actual ring
frequency. When the RFWE bit is 1, the RGDT pin is
asserted when the ring signal is positive or negative.
The output then appears to be twice the frequency of
the ring waveform.
The second method to monitor ring detection uses the
ring detect bits (RDTP, RDTN, and RDT). The RDTP
and RDTN behavior is based on the RNG1-RNG2
voltage. When the signal on RNG1-RNG2 is above the
positive ring threshold, the RDTP bit is set. When the
signal on RNG1-RNG2 is below the negative ring
threshold, the RDTN bit is set. When the signal on
RNG1-RNG2 is between these thresholds, neither bit is
set.
Rev. 1.5
The RDT behavior is also based on the RNG1-RNG2
voltage. When the RFWE bit is 0, a positive ring signal
sets the RDT bit for a period of time. When the RFWE
bit is 1, a positive or negative ring signal sets the RDT
bit.
The RDT bit acts like a one shot. When a new ring
signal is detected, the one shot is reset. If no new ring
signals are detected prior to the one shot counter
reaching 0, then the RDT bit clears. The length of this
count is approximately 5 seconds. The RDT bit is reset
to 0 by an off-hook event. If the RDTM bit
(Register 3, bit 7) is set, a hardware interrupt occurs on
the AOUT/INT pin when RDT is triggered. This interrupt
can
(Register 4, bit 7). When the RDI bit (Register 2, bit 2) is
set, an interrupt occurs on both the beginning and end
of the ring pulse as defined by the RTO bits
(Register 23, bits 6:3). Ring validation may be enabled
when using the RDI bit.
The third method to monitor detection uses the DTX
data samples to transmit ring data. If the ISOcap is
active (PDL=0) and the device is not off-hook or in
on-hook line monitor mode, the ring data is presented
on DTX. The waveform on DTX depends on the state of
the RFWE bit.
When RFWE is 0, DTX is –32768 (0x8000) while the
RNG1-RNG2 voltage is between the thresholds. When
a ring is detected, DTX transitions to +32767 when the
ring signal is positive, then goes back to –32768 when
the ring is near 0 and negative. Thus a near square
wave is presented on DTX that swings from –32768 to
+32767 in cadence with the ring signal.
When RFWE is 1, DTX sits at approximately +1228
while the RNG1-RNG2 voltage is between the
thresholds. When the ring becomes positive, DTX
transitions to +32767. When the ring signal goes near 0,
DTX remains near 1228. As the ring becomes negative,
the DTX transitions to –32768. This repeats in cadence
with the ring signal.
To observe the ring signal on DTX, watch the MSB of
the data. The MSB toggles at the same frequency as
the ring signal independent of the ring detector mode.
This method is adequate for determining the ring
frequency.
Si3050 + Si3011/18/19
be
cleared
by
writing
to
the
RDTI
bit
33