IDT82V1671AJ IDT, Integrated Device Technology Inc, IDT82V1671AJ Datasheet - Page 27

• Manufacturer Part Number: IDT82V1671AJ
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT82V1671AJ

• Number Of Channels: 4
• On-hook Transmission: Yes
• Polarity Reversal: Yes
• On-chip Ring Relay Driver: Yes
• Operating Supply Voltage (typ): 3.3V
• Operating Temp Range: -40C to 85C
• Package Type: PLCC
• Operating Temperature Classification: Industrial
• Pin Count: 28
• Mounting: Surface Mount
• Operating Current: 95mA
• Operating Supply Voltage (max): 3.465V
• Operating Supply Voltage (min): 3.135V
• Lead Free Status / RoHS Status: Compliant

3.5
The RSLIC senses the longitudinal and transversal line currents on the
Ring and Tip lines, and feeds the corresponding voltages to the CODEC
via the VL, VTAC and VTDC pins for further process. In this way, the
signaling in the subscriber loop is monitored.
Table - 4 Off-hook Detection in Different Modes
senses the transversal current on the Ring and Tip lines, and feeds the
corresponding voltage to the CODEC via VTDC pin. Inside the CODEC,
this voltage is A-to-D converted and filtered. The result is compared with
the programmed off-hook threshold (word HKthld in the Coe-RAM). If
the result exceeds the threshold, the bit HK[n] (n = 0, 1, 2 or 3) in
register GREG26 will be set to 1, indicating that Channel n+1 is off-hook.
All of the function blocks except off-hook detection stop working. The
transversal current on the Ring and Tip lines is sensed by a simple
sense circuit and the corresponding sensed voltage is fed to an analog
comparator in the CODEC via the VTAC pin. By comparing this sensed
voltage with a fixed off-hook threshold of 2 mA, the off-hook event can
be detected. Once the loop goes off-hook, the whole chipset should be
set to active mode by the master processor.
hook detection circuit to eliminate disturbance. The transversal DC
signal (which is taken as the off-hook criterion) will be filtered by this
debounce filter. The DC signal with duration less than the debounce time
Note: The operating mode of the CODEC is set by register LREG6. The operating mode of the RSLIC is set by register LREG6 (for MPI mode) or downstream C/I
channel byte. Refer to
RSLIC & CODEC CHIPSET
Chipset Mode
Supervision is performed internally by the RSLIC-CODEC chipset.
• Active mode
In this mode, both the RSLIC and the CODEC are active. The RSLIC
• Sleep mode
In this mode, both the CODEC and the RSLIC are in standby mode.
The CODEC integrates a programmable debounce filter in the off-
Active
Sleep
SUPERVISION
CODEC Mode
“6.1 Operating Modes” on page 87
Standby
Active
RSLIC Mode
Standby
Active
Hook State
Indication
Figure - 13 Hysteresis for Off-Hook Detection
for further details.
MPI mode:
GCI mode:
MPI mode:
GCI mode:
Threshold
On-hook
Hysteresis
LREG6: ACTIVE = 1, SCAN_EN = 1, SM[2:0] = 000
LREG6: ACTIVE = 1; downstream C/I channel byte: SCAN_EN = 1, SM[2:0] = 000
LREG6: STANDBY = 1, SCAN_EN = 1, SM[2:0] = 110
LREG6: STANDBY = 1; downstream C/I channel byte: SCAN_EN = 1, SM[2:0] = 110
27
Threshold
Off-hook
3.5.1
subscriber loop is closed by the hook switch inside the subscriber
equipment. For the RSLIC-CODEC chipset, the off-hook detection can
be operated in two different modes as shown in
An interrupt will be generated at the same time if the off-hook mask bit
HK_M in register LREG18 is disabled (‘0’).
the on-hook threshold should be used. The off-hook threshold minus a
programmable hysteresis value is the on-hook threshold (as shown in
Figure -
RAM. The default value is 2 mA.
will be ignored. As shown in
allows the debounce interval programmable from 0.125 ms to 2 ms. A
16-state up/down counter follows, resulting in the minimal debounce
time ranging from 2 ms to 32 ms. The debounce interval is programmed
by the DB[3:0] bits in LREG11.
mode to the active mode, there might be a narrow pulse of about 15 ms
occurring on VTDC, resulting in a false off-hook interrupt to be
generated. If this happens, please set the debounce time for off-hook
detection to 15 ms or above (i.e., DB[3:0] ≥ 0111B) to filter the noise
pulse.)
hook detection.
Loop start signaling is the most common type of signaling. The
In active mode, to detect the loop transition from off-hook to on-hook,
(Note: When the RSLIC operating mode is switching from other
Table - 5
13). The hysteresis value is programmed by HKHyst in the Coe-
Mode Control Register Setting
OFF-HOOK DETECTION
shows the registers and Coe-RAM locations used for off-
IDT82V1671/IDT82V1671A, IDT82V1074
I
Figure -
14, a four-bit debounce counter
Table -
4.