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參數(shù)資料
| 型號(hào)： | HC5503CBZ96 |
| 廠商： | INTERSIL CORP |
| 元件分類： | 模擬傳輸電路 |
| 英文描述： | Low Cost 24V SLIC For PABX / Key Systems |
| 中文描述： | TELECOM-SLIC, PDSO24 |
| 封裝： | GREEN, PLASTIC, MS-013AD, SOIC-24 |
| 文件頁數(shù)： | 10/17頁 |
| 文件大?。?/td> | 386K |
| 代理商： | HC5503CBZ96 |
10
The longitudinal amplifier’s principal function is Ring Trip
Detection. The output of the amplifier after being filtered by R
20
and C
2
to attenuate AC signals is fed into a detector whose
output inhibits the ring relay driver to remove ringing signals
from the line in an off-hook condition, reference Figure 8.
Ringing The Line
The Ring Command (RC) input is taken low during ringing.
This activates the ring relay driver (RD) output providing the
telephone is not off-hook or the line is not in a power denial
state. The ring relay connects the ring generator to the
subscriber loop. The ring generator output is usually an
80V
RMS
20Hz signal. The ring signal should not exceed
150V peak. Since the telephone ringer is AC coupled only
ring current will flow. This ringing current flows directly into
V
BAT
via a set of relay contacts. The high impedance
terminal RFS is provided so that the low impedance V
RF
node can be isolated from the hot end of the ring path in the
battery referenced ring scheme.
The AC ring current flowing in the subscriber circuit will be
sensed across R
B2
and will give rise to an AC voltage at the
output of the longitudinal amplifier. R
20
and C
2
attenuate
this signal before it reaches the ring trip detector to prevent
false ring trip. C
2
is nominally set at 1.0
μ
F.
When the subscriber goes off-hook, a DC path is established
between the output of the ring generator and the battery
ground or V
BAT
terminal. A DC longitudinal imbalance is
established since no tip feed current is flowing through the
tip feed resistors. The longitudinal amplifier output is driven
negative. Once it exceeds the ring trip threshold of the ring
trip detector, the logic circuitry is driven by GK to trip the ring
relay establishing an off-hook condition such that SHD will
become active as loop metallic current starts to flow.
In addition to its ability to be used for tip or ring injected
systems, the HC5503 can also be configured for systems
utilizing balanced ringing. The main advantage of balanced
ringing is that it tends to minimize cross coupling effects owing
to the differential nature of the ring tone across the line.
Figure 5 illustrates the sequence of events during ring trip with
ring synchronization for a tip injected ring system. Note that
owing to the 90
degree
phase shift introduced by the low pass
filter (R
20
, C
2
) the RS pulse will occur at the most negative
point of the attenuated ring signal that is fed into the ring trip
detector. Hence, when DC conditions are established for
SHD, the AC component actually assists ring trip taking place.
For a ring side injected ring system, the RS pulse should
occur at the positive zero crossing of the ring signal as it
appears at RFS If ring synchronization is not used, then the
RS pin should be held permanently to a logic high of 5V
nominally: ring trip will occur asynchronously with respect to
the ring voltage. Ring trip is guaranteed to take place within
three ring cycles after the telephone going off-hook.
It is recommended that an RC snubber network is placed
across the ring relay contacts to minimize inductive kick-
back effects from the telephone ringer. Typical values for
such a network are shown in Figure 10.
Transhybrid Circuit
The purpose of the transhybrid circuit is to remove the
receive signal (R
X
) from the transmit signal (T
X
), thereby
preventing an echo on the transmit side. This is
accomplished by using an external op amp (usually part of
the CODEC) and by the inversion of the signal from the
4-wire receive port (R
X
) to the 4-wire transmit port (T
X
).
Figure 6 shows the transhybrid circuit. Because the voltage
at R
X
is 180 degrees out of phase with the voltage at T
X
the
input signal will be subtracted from the output signal if I
1
equals I
2
Node analysis yields the following Equation:
The voltage at T
X
is the product of the 4-wire to 2-wire
(A
4-2
= 0.633) and 2-wire to 4-wire (A
2-4
= -1.0) voltage
gains, and is therefore equal to 0.633. The voltage at R
X
,
when taking into account the negative feedback through R
2
,
HC5503 I
LOOP
SATURATION
I
L
R
LOOP
(
)
533
0
20
30
R
LOOP
= R
B1
+ R
B2
+ Z
TF
+ Z
RF
+ R
LINE
+ R
SET
10
FIGURE 4. DC LOOP CURRENT CHARACTERISTICS
FIGURE 5. RING TIP SEQUENCE
150V
V
RING
150V
PEAK
,
MAX
>50
μ
s
C
2
CHARGES
TO 0V
QUIESCENT
VALUE
RING RELAY
HAS TRIPPED
DC SHIFT OWING TO
DC CURRENT DIFFERENCE
BETWEEN I
TIP
AND I
RING
SUBSCRIBER
GOES OFF-HOOK
RING
TRIP
THRESHOLD
0V
0V
5V
RS
V
C4
I
1
I
2
+
T
X
R
4
------
R
X
R
3
-------
+
0
=
=
(EQ. 24)
HC5503
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| HC5503CCP | Bipolar Transistor; Collector Emitter Voltage, Vceo:50V; Transistor Polarity:NPN; Power Dissipation:900mW; DC Current Gain Min (hfe):180; Collector Current:500A; Package/Case:3-TO-92 |
| HC5503CCB | Unbalanced PBX/Key System SLIC, Subscriber Line Interface Circuit |
| HC5503TCB | Bipolar Transistor; Collector Emitter Voltage, Vceo:50V; Transistor Polarity:NPN; Power Dissipation:900mW; DC Current Gain Min (hfe):180; Collector Current:500A; Package/Case:3-TO-92 |
| HC5503TCP | Bipolar Transistor; Collector Emitter Voltage, Vceo:50V; Transistor Polarity:PNP; Power Dissipation:900mW; DC Current Gain Min (hfe):180; Collector Current:500A; Package/Case:3-TO-92 |
| HC5504B | EIA/ITU PABX SLIC with 40mA Loop Feed |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| HC5503CCB | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| HC5503CCP | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| HC5503CM | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| HC5503CM96 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Subscriber Line Interface Circuit |
| HC5503PRC | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Low Cost SLIC For Large Telecom Switches |
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