IDT82V1671AJ IDT, Integrated Device Technology Inc, IDT82V1671AJ Datasheet - Page 46

• 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

3.9.6.3
DC voltage (V
current via the VTDC pin. The following steps are necessary to
accomplish the loop resistance measurement:
measurement.
offset can be compensated or the measurement can be done
differentially. The latter eliminates both the current and voltage offsets.
sequence below:
RSLIC & CODEC CHIPSET
The DC loop resistance can be determined by supplying a constant
• Program a certain ring offset voltage (Refer to
• Set the RSLIC to Normal Active mode (for MPI interface, LREG6:
• Select VTDC as the level meter source (LM_SRC = 0; DC_SRC =
• The transversal current (I
• Based on the known constant output voltage V
Figure - 24
In order to increase the accuracy of the result, either the current
To measure the loop resistance R
• Program a certain ring offset voltage and apply it to the Tip/Ring
• Set the RSLIC to Normal Active mode (for MPI interface, LREG6:
R
I
LINE
LINE
R
Ringing Generation” on page 23
Tip/Ring pair;
SCAN_EN = 1, SM[2:0] = 000; for GCI interface, downstream C/I
channel: SCAN_EN = 1, SM[2:0] = 000). Set the CODEC to Ring
Pause mode (for both MPI and GCI interfaces, LREG6: RING = 1,
RING_EN = 0).
1; LM_SEL[3:0] = 0000);
level meter result registers (GREG17 and GREG18);
sured I
noted that the calculated resistance also includes the on board
sense resistors.
pair via the RSLIC;
SCAN_EN = 1, SM[2:0] = 000; for GCI interface, downstream C/I
channel: SCAN_EN = 1, SM[2:0] = 000). Set the CODEC to Ring
Loop
Figure - 24 Example for Resistance Measurement
=
Loop Resistance Measurement
Trans
Line Card
TRDC
V
---------------- -
R
R
I
V
Trans
PROT
PROT
TRDC
TRDC
current, the resistance can be calculated. It should be
shows an example circuit for loop resistance
) to the Tip/Ring pair and measuring the DC loop
V
: DC voltage programmed by the Coe-RAM (word RingOffset)
TRDC
R
R
Sense
=
Sense
V
TRDC
RSLIC
Trans
⁄


) can be determined by reading the
------------------------------------------------------------------------- -
K
ADDC
for details) and apply it to the
line sense signal to be measured
Loop
×
VTDC
DCN
DCP
K
VL
INT
differentially, follow the
LM
×
Result
N
TRDC
Samples
“3.4.1.1 Internal
CODEC
and the mea-
×
K
ITDC


46
R
measurement method.
offset caused by the RSLIC current sensor and the voltage offset
caused by the DC voltage output (ring offset voltage). The following
calculation shows the elimination of both offsets.
3.9.6.4
setting the Ring and Tip lines to high impedance respectively. When one
line is set to high impedance, the other line is still active and is able to
supply a known voltage. By measuring the DC transversal current, the
line impedance can be determined.
I
I
I
Measure normal
Measure normal
Measure reverse
Loop
• Select VTDC as the level meter source (LM_SRC = 0; DC_SRC =
• Read level meter result registers GREG17 and GREG18.
• Reverse the voltage between Tip and Ring lines by setting the
• Read level meter result registers GREG17 and GREG18.
Figure - 25
This differential measurement method eliminates both the current
V
I
The line resistance Tip/GND and Ring/GND can be measured by
Offset:
Offset:
Reverse Polarity
Pause mode (for both MPI and GCI interfaces, LREG6: RING = 1,
RING_EN = 0).
1; LM_SEL[3:0] = 0000);
REV_POL bit in LREG19 to 1.
=
(
(
(
Figure - 25 Differential Resistance Measurement
------------------------------------------------------------------------
I
Measure normal
offset voltage caused by the DC voltage output;
offset current caused by the RSLIC current sensor;
Line Resistance Tip/GND and Ring/GND
Offsets
)
)
)
–
=
describes the offset elimination by the differential
=
(
I
Measure reverse
V
--------------------------------- -
U
–
-------------------------------------
2
TRDC
offset
V
I
×
TRDC
Tip/Ring
)
IDT82V1671/IDT82V1671A, IDT82V1074
R
V
–
(
R
I
Loop
+
TRDC
offset
I
Loop
Measure reverse
+
V
Offset
V
Offset
)
expected values
=
(
+
dU
2
---------------------- -
+
I
Offset
×
Normal Polarity
R
I
Offset
V
Loop
)
TRDC
=
R
dI
LINE
measured values
+
R
Sense
V
Tip/Ring
+
R
PROT