- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383602 > MH88628 (Mitel Networks Corporation) Central Office SLIC(用于中央辦公線卡的用戶線接口電路) PDF資料下載
參數(shù)資料
| 型號(hào)： | MH88628 |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | Central Office SLIC(用于中央辦公線卡的用戶線接口電路) |
| 中文描述： | 中央辦公室用戶接口（用于中央辦公線卡的用戶線接口電路） |
| 文件頁(yè)數(shù)： | 6/17頁(yè) |
| 文件大?。?/td> | 91K |
| 代理商： | MH88628 |
MH88628
Preliminary Information
2-206
Functional Description
The SLIC uses a transformerless electronic 2-wire to
4-wire conversion which can be connected to a
Codec to interface the 2 wire subscriber loops to a
time
division
multiplexed
modulated (PCM) digital switching network. For
analog applications, the Tx and Rx of the 2-4 wire
converter can be connected directly to an analog
crosspoint switch such as the MT8816. Powering of
the line is provided through precision battery feed
resistors. The MH88628 also contains control,
signalling and status circuitry which combines to
provide a complete functional solution which
simplifies the manufacture of line cards. This circuitry
is illustrated in the functional block diagram in Fig. 1.
The MH88628 is designed to be pin compatible with
Mitel’s MH88632 and MH88625. This allows a
common PCB design with common gain, input
impedance and network balance.
(TDM)
pulse
code
Approvals
FCC part 68, CCITT, DOC CS-03, UL 1459, CAN/
CSA 22.2 No.225-M90 and ANSI/EIA/TIA-464-A are
system level safety standards and performance
requirements. As a component of a system, the
MH88628 is designed to comply with the applicable
requirements of these specifications.
Battery Feed
The loop current for the subscriber equipment is
sourced through a pair of matched 200
resistors
connected to the Tip and Ring. The two wire loop is
biased such that the Ring lead is 2V above VBat
(typically -46V) and the Tip lead is 2V below LPGD
(typically -2V) during constant voltage, constant
current mode.
The SLIC is designed for a nominal battery voltage
of -48Vdc and can provide the maximum loop current
of 45mA under the condition.
The MH88628 is designed to operate down to a
minimum of 16mA dc, with a battery voltage of -44V.
The Tip and Ring output drivers can operate within
2V of V
Bat
and LGND rails. This permits a maximum
loop range of 2300
.
Loop Current Setting
The MH88628 SLIC is a constant current with
constant voltage fallback design. This design feature
provides for long loop capability regardless of the
constant current setting. Refer to Graph 1.
The LCA (Loop Current Adjust) pin is an input to an
internal resistor divider network which generates a
bias voltage. The loop current is proportional to this
voltage. The loop current can be set between 20 and
45mA by various connections to the LCA pin as
illustrated in Table 5 and Figure 8. The loop current
during a fault condition will be limited to a safe level.
Primary over-current protection is inherent in the
current limiting feature of the 200
battery feed
resistors. Refer to Graph 1.
Receive and Transmit Audio Path
The audio signal of the 2-wire side is sensed
differentially across the external 200
feed resistors
and is passed on to a second differential amplifier
stage in the 2W/4W conversion block. This block sets
the transmit gain on the 4-wire side and cancels
signals originating from the receive input before
outputting the signal.
Programmable Transmit and Receive
Gain
Transmit Gain (Tip-Ring to Tx) and Receive Gain (Rx
to Tip-Ring) are programmed by connecting external
resistors (RRX and RRT) from GRXI to AGND and
from GTX1 to AGND as indicated in Figure 3 and
Tables 1 and 2. The programmable gain range is
from -12dB to +6dB; this wide range will
accommodate any loss plan. Alternatively, the
default Receive Gain of 0dB and Transmit Gain of
0dB can be obtained by connecting GRX0 to GRX1
and GTX0 to GTX1. In addition, a Receive gain of
+6dB and Transmit Gain of +6dB can be obtained by
not connecting resistors RRX and RTX. For correct
gain
programming,
the
impedance (Z
in
) must match the line termination
impedance.
MH88628’s
Tip-Ring
For optimum performance, resistor RRX should be
physically located as close as possible to the GRX1
input pin, and resistor RTX should be physically
located as close as possible to the GTX1 input pin.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MH88631-2 | Central Office Interface (LS/GS) Preliminary Information |
| MH88631 | Central Office Interface (LS/GS) Preliminary Information |
| MH88631-1 | Central Office Interface (LS/GS) Preliminary Information |
| MH88632B | Central Office Interface Circuit(用于中央辦公電話線的接口電路（在音頻轉(zhuǎn)換設(shè)備和用戶線之間提供一個(gè)模擬和信號(hào)連接）) |
| MH88632B | Central Office Interface Circuit Preliminary Information |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MH88630 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface (LS/GS) Preliminary Information |
| MH88631 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface (LS/GS) Preliminary Information |
| MH88631-1 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface (LS/GS) Preliminary Information |
| MH88631-2 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface (LS/GS) Preliminary Information |
| MH88632 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Central Office Interface Circuit Preliminary Information |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。