SI3210DCQ1-EVB Silicon Laboratories Inc, SI3210DCQ1-EVB Datasheet - Page 39

• Manufacturer Part Number: SI3210DCQ1-EVB
• Description: DAUGHTERCARD W/SI3201 INTERFACE
• Manufacturer: Silicon Laboratories Inc
• Series: ProSLIC®r
• Type: SLIC/CODECr

Specifications of SI3210DCQ1-EVB

• Contents: Evaluation Board and CD-ROM
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Si3210
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

where
transistors Q5 and Q6.
The minimum value for VBATH is therefore given by the
following:
The ProSLIC is designed to create a fully balanced
ringing waveform, meaning that the TIP and RING
common mode voltage, (V
voltage
automatically set to the following:
VCMR is an indirect register which provides the
headroom by the ringing waveform with respect to the
VBATH rail. The value is set as a 4-bit setting in indirect
Register 40 with an LSB voltage of 1.5 V/LSB.
Register 40 should be set with the calculated V
provide voltage headroom during ringing.
Silicon revisions C and higher support the option to
briefly increase the maximum differential current limit
between the voltage transition of TIP and RING from
ringing to a dc linefeed state. This mode is enabled by
setting ILIMEN = 1 (direct Register 108, bit 7).
LCS
V
β
OVR
is
VBATH
is the minimum expected current gain of
VCM_RING
Processor
=
referred
Signal
Input
I
LOAD , PK
LFS
=
V
AC , PK
=
ISP_OUT
×
to
β
------------ -
VBATH VCMR
--------------------------------------------- -
TIP
+
β
+
as
1
V
+ V
×
ROFF
(
80.6 Ω
2
VCM_RING
–
RING
Digital
NRTP
+
LPF
V
)/2, is fixed. This
OVR
+
1 V
Figure 23. Ring Trip Detector
)
Threshold
Ring Trip
RPTP
and
OVR
Rev. 1.42
+
–
to
is
2.4.6. Ring Trip Detection
A ring trip event signals that the terminal equipment has
gone off-hook during the ringing state. The ProSLIC
performs ring trip detection digitally using its on-chip A/
D converter. The functional blocks required to
implement ring trip detection is shown in Figure 23. The
primary input to the system is the loop current sense
(LCS) value provided by the current monitoring circuitry
and reported in direct Register 79. LCS data is
processed by the input signal processor when the
ProSLIC is in the ringing state as indicated by the
Linefeed Shadow register (direct Register 64). The data
then feeds into a programmable digital low pass filter,
which removes unwanted ac signal components before
threshold detection.
The output of the low pass filter is compared to a
programmable threshold, RPTP (indirect Register 29).
The threshold comparator output feeds a programmable
debouncing filter. The output of the debouncing filter
remains in its present state unless the input remains in
the opposite state for the entire period of time
programmed by the ring trip debounce interval,
RTDI[6:0] (direct Register 70). If the debounce interval
has been satisfied, the RTP bit of direct Register 68 will
be set to indicate that a valid ring trip has occurred. A
ring trip interrupt is generated if enabled by the RTIE bit
(direct Register 22). Table 31 lists the registers that
must be written or monitored to correctly detect a ring
trip condition.
The recommended values for RPTP, NRTP, and RTDI
vary according to the programmed ringing frequency.
Register values for various ringing frequencies are
given in Table 32.
DBIRAW
Debounce
Filter
RTDI
Si3210/Si3211
RTP
Interrupt
Logic
RTIE
RTIP
39