- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄371775 > HC55171IM (INTERSIL CORP) 5 REN Ringing SLIC for ISDN Modem/TA and WLL PDF資料下載
參數(shù)資料
| 型號： | HC55171IM |
| 廠商： | INTERSIL CORP |
| 元件分類： | 模擬傳輸電路 |
| 英文描述： | 5 REN Ringing SLIC for ISDN Modem/TA and WLL |
| 中文描述： | TELECOM-SLIC, PQCC28 |
| 封裝： | PLASTIC, MS-018AB, LCC-28 |
| 文件頁數(shù)： | 9/18頁 |
| 文件大?。?/td> | 153K |
| 代理商： | HC55171IM |
70
AC Voltage Gain Design Equations
The HC55171 uses feedback to synthesize the impedance
at the 2-wire tip and ring terminals. This feedback network
defines the AC voltage gains for the SLIC.
The 4-wire to 2-wire voltage gain (V
RX
to V
TR
) is set by the
feedback loop shown in Figure 7. The feedback loop senses
the loop current through resistors R
S1
and R
S2
, sums their volt-
age drop and multiplies it by 2 to produce an output voltage at
the V
TX
pin equal to +4R
S
I
L
. The V
TX
voltage is then fed into
the -IN1 input of the SLIC’s internal op amp. This signal is multi-
plied by the ratio R
Z0
/R
RF
and fed into the tip current summing
node via the OUT1 pin. (Note: the internal V
BAT
/2 reference
(ring feed amplifier) and the internal +2V reference (tip feed
amplifier) are grounded for the AC analysis.)
The current into the summing node of TF amp is equal to:
Equation 9 is the node equation for the tip amplifier summing
node. The current in the tip feedback resistor (I
R
) is given in
Equation 7.
The AC voltage at V
C
is then equal to:
and the AC voltage at V
D
is:
The values for R
Z0
and R
RF
are selected to match the
impedance
requirements
on
information refer to AN9607 “Impedance Matching Design
Equations for the HC5509 Series of SLICs”. The following
loop current calculations will assume the proper R
Z0
and
R
RF
values for matching a 600
load.
The loop current (
I
L
) with respect to the feedback network, is
calculated in Equations 14 through 17. Where R
Z0
= 40k
,
R
RF
= 40k
, R
L
= 600
,
R
P1
= R
P2
= R
S1
= R
S1
= 50
.
tip
and
ring,
for
more
Substituting the expressions for V
C
and V
D
Equation 15 simplifies to
Solving for
I
L
results in
V
Equation 17 is the loop current with respect to the feedback
network. From this, the 4-wire to 2-wire and the 2-wire to
4-wire AC voltage gains are calculated. Equation 18 shows
the 4-wire to 2-wire AC voltage gain is equal to 1.00.
Equation 19 shows the 2-wire to 4-wire AC voltage gain is
equal to -0.333.
Impedance Matching
The feedback network, described above, is capable of
synthesizing both resistive and complex loads. Matching the
SLIC’s 2-wire impedance to the load is important to maxi-
mize power transfer and maximize the 2-wire return loss.
The 2-wire return loss is a measure of the similarity of the
impedance of a transmission line (tip and ring) and the
impedance at it’s termination. It is a ratio, expressed in deci-
bels, of the power of the outgoing signal to the power of the
signal reflected back from an impedance discontinuity.
Requirements for Impedance Matching
Impedance matching of the HC55171 application circuit to the
transmission line requires that the impedance be matched to
points “A” and “B” in Figure 7. To do this, the sense and pro-
tection resistors R
P1
, R
P2
, R
S1
and R
S2
must be accounted
for by the feedback network to make it appear as if the output
of the tip and ring amplifiers are at points “A” and “B”. The
feedback network takes a voltage that is equal to the voltage
drop across the sense resistors and feeds it into the summing
node of the tip amplifier. The effect of this is to cause the tip
feed voltage to become more negative by a value that is pro-
portional to the voltage drop across the sense resistors R
P1
and R
S1
. At the same time the ring amplifier becomes more
positive by the same amount to account for resistors R
P2
and R
S2
.
The net effect cancels out the voltage drop across the feed
resistors. By nullifying the effects of the feed resistors the
I
OUT1
4R
I
L
--------------------
–
R
RF
-----------
=
(EQ. 8)
I
R
–
4R
I
L
--------------------
R
RF
-----------
–
V
-----------
+
0
=
(EQ. 9)
I
R
4R
I
L
--------------------
R
RF
-----------
–
V
-----------
+
=
(EQ. 10)
V
C
I
R
(
)
R
( )
=
(EQ. 11)
V
C
4
–
R
S
I
L
R
RF
-----------
V
RX
+
=
(EQ. 12)
V
D
4R
S
I
L
R
RF
-----------
V
RX
–
=
(EQ. 13)
I
L
V
P2
V
–
L
P1
R
S1
R
S2
+
+
---------+
=
(EQ. 14)
I
L
2
4
–
R
S
I
L
R
-----------
V
RX
+
×
L
P1
P2
R
S1
R
S2
+
+
---------+
=
(EQ. 15)
I
L
2V
----------------------------------------
400 I
L
–
=
(EQ. 16)
I
L
-----------
=
(EQ. 17)
A
4W
2W
–
V
RX
-----------
I
R
L
RX
(
)
--------------------
V
--------------------------
-----------
600
(
)
RX
1
=
=
=
=
(EQ. 18)
A
2W
4W
–
V
TR
------------------
4
–
R
S
I
L
-----------------------------------------
R
RF
-----------
L
L
200
---------------------------------
–
V
-----------
1
( )
-----------
600
(
)
1
3
--
–
=
=
=
=
(EQ. 19)
HC55171
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| HC55185BIM | VoIP Ringing SLIC Family |
| HC55185CIM | VoIP Ringing SLIC Family |
| HC55183ECM | Extended Reach Ringing SLIC Family |
| HC55180DIM | Extended Reach Ringing SLIC Family |
| HC55181AIM | Wirewound Resistors, type NH Non-Inductive Winding |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| HC5517B | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Low Cost 3 REN Ringing SLIC for ISDN Modem/TA and WL |
| HC5517B WAF | 制造商:Harris Corporation 功能描述: |
| HC5517BCB | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Harris Corporation 功能描述: |
| HC5517BCB96S2495 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| HC5517BCM | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。