IDT82V1671AJ IDT, Integrated Device Technology Inc, IDT82V1671AJ Datasheet - Page 17

• 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

3.2
3.2.1
voice signals in the transmit and receive directions superimposed. Thus,
once the telephone has gone off-hook, the SLIC must supply a DC
current to the subscriber line. The RSLIC-CODEC chipset provides a
fully programmable DC feeding characteristic to meet the requirements
of different applications.
current zone, the resistive zone and the constant voltage zone (see
Figure -
level AC signal.
3.2.2
as an ideal current source with an infinite internal resistance (R
Figure - 3.
usually must be kept at a constant level independent of the load. The
RSLIC senses the DC current and provides this information to CODEC
via the VTDC pin. The CODEC compares this value with the
programmed value and adjusts the RSLIC drivers as required.
RSLIC & CODEC CHIPSET
Analog telephones require a DC current in the off-hook state with AC
The DC feeding characteristic has three different zones: the constant
In applications of short local loops, the DC feeding can be considered
2). A voltage reserve V
I
I
TIP-RING
TIP-RING
When the loop is in the off-hook state, the feeding current
Constant current zone
DC FEEDING
DC FEEDING CHARACTERISTIC ZONES
CONSTANT CURRENT ZONE
R
Figure - 3 Constant Current Zone
I
Figure - 2 DC Feeding Zones
R
L
RES
is provided to avoid clipping the high
Resistive zone
Necessary Voltage Reserve V
Constant voltage zone
V
BAT
RES
V
V
TIP-RING
TIP-RING
I
), see
17
voltage V
load resistance R
indication bit FEED_I in register LREG21 will be set to 1, otherwise it is
set to 0.
3.2.3
especially applicable to medium line loops where the battery is unable to
feed a constant current to the line. In this zone, the DC feeding is
considered as a voltage source with a programmable internal resistance
(R
resistive zone, as shown in
bit FEED_R in register LREG21 will be set to 1, otherwise it is set to 0.
3.2.4
considered as a voltage source with zero internal resistance (R
depends on the load between the Tip and Ring lines. See
V
voltage.
indication bit FEED_V in register LREG21 will be set to 1, otherwise it is
set to 0.
RES
LIN
Depending on the load, the operating point is determined by the
V
Where, R
When the DC feeding is operating in the constant current zone, the
The resistive zone is flexible in a wide range of applications,
The operating point crosses from the constant current zone to the
When the DC feeding is operating in the resistive zone, the indication
In very high impedance loops (long loops), the DC feeding can be
In this zone, the voltage V
To avoid clipping the high level AC speech signals, a voltage reserve
Where, V
Normally, V
When the DC feeding is operating at the constant voltage zone, the
Tip/Ring
).
V
should be provided:
RES
I
Tip/Ring
TIP-RING
= R
=
BAT
L
RESISTIVE ZONE
CONSTANT VOLTAGE ZONE
represents the equivalent loop resistance. The lower the
RES
L
V
between the Tip and Ring lines as follows:
is the selected battery voltage, V
∗ I
L
BAT
, the lower the voltage V
= 2 V.
Tip/Ring
Figure - 4 Resistive Zone
–
IDT82V1671/IDT82V1671A, IDT82V1074
V
LIM
Figure -
Tip/Ring
R
LIN
4.
is constant and the current I
Tip/Ring
R
L
.
LIM
is the open circuit
Figure -
V
TIP-RING
V
5.
).
Tip/Ring