- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄367544 > LE79R251JC Telecommunication IC PDF資料下載
參數(shù)資料
| 型號： | LE79R251JC |
| 英文描述： | Telecommunication IC |
| 中文描述： | 通信集成電路 |
| 文件頁數(shù)： | 15/22頁 |
| 文件大?。?/td> | 533K |
| 代理商： | LE79R251JC |
P R E L I M I N A R Y
Le79R251 ISLIC Data Sheet
15
Operating Mode Descriptions
Driver Descriptions
Control bits RD1, RD2, and RD3 do not affect the operating mode of the Le79R251 device. These signals perform the following
functions:
Operating Mode
Description
Disconnect
This mode disconnects both A and B output amplifiers from the AD and BD outputs. The A and B amplifiers
are shut down and the Le79R251 device selects the low battery voltage at the VBL pin. In the Disconnect
state, the currents on IMT and ILG represent the voltages on the SA and SB pins, respectively. These
currents are scaled to produce voltages across RMTi and RLGi of
and
, respectively.
Standby
The power amplifiers are turned off. The AD output is driven by an internal 250
(typical) resistor, which
connects to ground. The BD output is driven by an internal 250
(typical) resistor, which connects to the
high battery (BATH) at the VBH pin, through a clamp circuit, which clamps to approximately –50 V with
respect to BGND. For VBH values above–55 V, the open-circuit voltage, which appears at this output is
~VBH + 8 V. If VBH is below –55 V, the voltage at this output is –50 V. The battery selection for the balance
of the circuitry on the chip is VBL. Line supervision remains active. Current limiting is provided on each line
to limit power dissipation under short-loop conditions as specified in the “Le79R251 device Current-Limit
Behavior” section. In external ringing, the standby ISLIC state is selected.
Tip Open
In this mode, the AD (Tip) lead is opened and the BD (Ring) lead is connected to a clamp, which operates
from the high battery on VBH pin and clamps to approximately –50 V with respect to BGND through a resistor
of approximately 250
(typical). The battery selection for the balance of the circuitry on the chip is VBL.
In the Active High Battery mode, battery connections are connected as shown in “Operating Modes” on
page 14. Both output amplifiers deliver the full power level determined by the programmed DC-feed
conditions. Active High Battery mode is enabled during a call in applications when a long loop can be
encountered. SBAT = VBH.
Active High Battery
Active Low Battery
Both output amplifiers deliver the full power level determined by the programmed DC-feed conditions. VBL,
the low negative battery, is selected in the Active Low Battery mode. This is typically used during the voice
part of a call. SBAT = VBL.
Active Boosted
Battery
In the Active Boosted Battery mode, battery connections are as shown in “Operating Modes” on page 14.
Both output amplifiers deliver the power level determined by the programmed DC-feed conditions. Active
Boosted Battery mode is enabled during a call in applications when an extended loop can be encountered.
SBAT = VBP - VBH.
Active Internal
Ringing
In the Internal Ringing mode, the Le79R251 device selects the battery connections as shown in “Operating
Modes” on page 14. When using internal ringing, both the AD and BD output amplifiers deliver the ringing
signal determined by the programmed ringing level. SBAT = VBP - VBH.
On-Hook
Transmission
(OHT), Fixed
Longitudinal
Voltage
In the On-Hook Transmission, Fixed Longitudinal Voltage mode, battery connections are as shown in
“Operating Modes” on page 14. The longitudinal voltage is fixed (as defined in the Table , “Operating Modes,”
on page 14) to allow compliance with safety specifications for some classes of products, such as ones
needing to meet the requirements of UL1950. SBAT = VBH.
Driver
Description
R1
A logic 1 on RD1 turns the R1 driver on and operates a relay connected between the R1 pin and VCCD. R1
drives the ring relay when external ringing is selected.
R2
A logic 1 on the RD2 signal turns the R2 driver on and routes current from the R2 pin to the RYE pin. In the
option where the RYE pin is connected to ground, the R2 pin can sink current from a relay connected to VCCD.
Another option is to connect the RYE pin to the BD (Ring) lead and connect a test load between R2 and the
AD(Tip) lead. This technique avoids the use of a relay to connect a test load. However, it does not isolate the
subscriber line from the line card. The test load must be connected to the Le79R251 device side of the
protection resistor to avoid damage to the R2 driver.
R3
A logic 1 on the RD3 signal turns the R3 driver on and routes current from the R3 pin to the RYE pin. In the
option where the RYE pin is connected to ground, the R3 pin can sink current from a relay connected to VCCD.
Another option is to connect the RYE pin to the B (Ring) lead and connect a test load between R3 and the A(Tip)
lead. This technique avoids the use of a relay to connect a test load. However, it does not isolate the subscriber
line from the line card. The test load must be connected to the Le79R251 device side of the protection resistor
to avoid damage to the R3 driver.
V
400
----------
V
400
----------
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LEA20033 | ASIC |
| LEA20040 | ASIC |
| LEA20046 | ASIC |
| LEA20056 | ASIC |
| LEA20066 | ASIC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LE79R70-1DJC | 制造商:Microsemi Corporation 功能描述:SLIC 1CH 40DB 110MA 5V 32PLCC - Rail/Tube 制造商:MICROSEMI CONSUMER MEDICAL PRODUCT GROUP 功能描述:IC SLIC 1CH 40DB LGBAL 32PLCC |
| LE79R70-1DJCT | 制造商:Microsemi Corporation 功能描述:1CH SLIC 40DB LGBAL P RV PL32TR 制造商:Microsemi Corporation 功能描述:SLIC 1CH 40DB 110MA 5V 32PLCC - Tape and Reel 制造商:MICROSEMI CONSUMER MEDICAL PRODUCT GROUP 功能描述:IC SLIC 1CH 40DB LGBAL 32PLCC 制造商:Microsemi Corporation 功能描述:IC SLIC 1CH 40DB LGBAL 32PLCC |
| LE79R70-1FQC | 制造商:Microsemi Corporation 功能描述:SLIC 1CH 40DB 110MA 5V 32QFN EP - Trays 制造商:Microsemi Corporation 功能描述:SINGLE SLIC SHORT LOOP LONG-BAL POL REV 制造商:Zarlink Semiconductor Inc 功能描述:SINGLE SLIC SHORT LOOP LONG-BAL POL REV |
| LE79R70-1FQCT | 制造商:Microsemi Corporation 功能描述:SLIC 1CH 40DB 110MA 5V 32QFN EP - Tape and Reel |
| LE79R70DJC | 制造商:Microsemi Corporation 功能描述:SLIC 1CH 40DB 110MA 5V 32PLCC - Rail/Tube 制造商:MICROSEMI CONSUMER MEDICAL PRODUCT GROUP 功能描述:IC SLIC 1CH 40DB LGBAL 32PLCC 制造商:Microsemi Corporation 功能描述:IC SLIC 1CH 40DB LGBAL 32PLCC |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。