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參數資料
| 型號： | 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： | 6/17頁 |
| 文件大小： | 386K |
| 代理商： | HC5503CBZ96 |
6
Design Information
Line Feed Amplifiers
The line feed amplifiers are high power operational
amplifiers and are connected to the subscriber loop through
150
of feed resistance as shown in Figure 1. The feed
resistors and synthesized impedance via feedback provide a
600
balanced load for the 2-wire to 4-wire transmission.
The tip feed amplifier is configured as a unity gain
noninverting buffer. A -4V bias (derived from the negative
battery (V
BAT
) in the bias network) is applied to the input of
the amplifier. Hence, the tip feed DC level is at -4V. The
principal reason for this offset is to accommodate sourcing
and sinking of longitudinal noise currents up to 15mA
RMS
without saturating the amplifier output and to provide
sufficient overhead for receive signals. The tip feed amplifier
also feeds the ring feed amplifier, which is configured as a
unity gain inverting amplifier as seen from the tip feed
amplifier. The noninverting input to the ring feed amp is
biased at a V
BAT
/2. Looking into this terminal the amplifier
has a noninverting gain of 2. Thus, the DC output at ring
feed is:
V
RF
(DC) = (4 + V
BAT
) Volts
For a -24V battery, V
RF
= -20V. Hence, the nominal battery
feed across the loop provided by the SLIC is 16V. When the
subscriber goes off-hook this DC feed causes current
(metallic current) to flow around the loop.
The received audio signal RX is fed into the tip feed amplifier
and appears at the tip feed terminal. It is also fed through the
ring feed amplifier and is inverted. Thus, a differential signal
of 2V
RX
appears between tip feed and ring feed. The R
X
signal causes AC audio currents to flow around the loop
which are then AC coupled to the earpiece of the telephone
set.
2-Wire Impedance Matching
The HC5503 is optimized for operation with a -24V battery.
Impedance matching to a 600
load, is achieved through
the combination of the feed resistors (R
B1
, R
B2
) and
negative feedback through resistor R
2
(reference Figure 1).
R
B1
and R
B2
are sense resistors that detect loop current
and provide negative feedback to synthesize the remaining
300
required to match a 600
line.
The impedance looking into the tip terminal is 150
(R
B1
)
plus the synthesized impedance of the tip amplifier. The
synthesized tip impedance is equal to the tip feed voltage Va
divided by
IL. (Note, the tip feed amplifier is a voltage
follower. Thus, the tip feed voltage is equal to the receive
input voltage V
RX
, both are labeled Va.) The synthesized
impedance of the ring terminal is calculated the same way
and is the ring feed voltage divided by
IL. (Note, the ring
feed voltage is equal in magnitude to the tip feed voltage, but
opposite in phase as a result of the ring feed amplifier gain.)
TIP
150
TIP FEED
-
+
90k
-
+
4V
DC
(NOTE)
C
3
R
3
TO TRANSHYBRID OP-AMP
R
1
INPUT
FROM
CODEC
-
+
+
-
+2
C
4
4RS
I
L
+
+4RS
I
L
+
-
RING FEED
R
B2
150
-
I
L
+
RING
V
BAT
2
(NOTE)
R
R
HC5503
Z
IN
R
B1
= R
B2
= R
S
= 150
-
+
V
IN
R
2
Va
RX
TX
R
B1
I
L
+
-
NOTE: Grounded for AC analysis.
FIGURE 1. IMPEDANCE MATCHING CIRCUITRY
HC5503
相關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 |
相關代理商/技術參數 |
參數描述 |
|---|---|
| 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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