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参数资料
| 型号： | ATTL7554BP |
| 英文描述： | L7554 Low-Power SLIC |
| 中文描述： | L7554低功耗用户接口 |
| 文件页数： | 22/28页 |
| 文件大小： | 486K |
| 代理商： | ATTL7554BP |
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22
Lucent Technologies Inc.
Data Sheet
March 1997
L7554 Low-Power SLIC
Applications
(continued)
dc Applications
(continued)
Adjusting dc Feed Resistance
The dc feed resistance may be adjusted with the help of
Figure 28.
12-2560 (C)
Figure 28. Equivalent Circuit for Adjusting the dc
Feed Resistance
Adjusting Overhead Voltage and dc Feed
Resistance Simultaneously
The following paragraphs describe the independent set-
ting of the overhead voltage and the dc feed resistance.
If both need to be set to customized values, combine
the two circuits as shown in Figure 29.
12-2561 (C)
Figure 29. Adjusting Both Overhead Voltage and dc
Feed Resistance
This is an equivalent circuit for adjusting both the dc
feed resistance and overhead voltage together.
The adjustments can be made by the simple superposi-
tion of the overhead and dc feed equations:
When selecting external components, select R1 on the
order of 5 k
to minimize the programming inaccuracy
caused by the internal 25 k
resistor. Lower values can
be used; the only disadvantage is the power consump-
tion of the external resistors.
Loop Range
The equation below can be rearranged to provide the
loop range for a required loop current:
Off-Hook Detection
The loop closure comparator has built-in longitudinal
rejection, eliminating the need for an external 60 Hz fil-
ter. This applies in both powerup and low-power scan
states. The loop-closure detection threshold is set by
resistor R
LCTH
. Referring to Figure 30, NLC is high in an
on-hook condition (I
TR
= 0, V
DCOUT
= 0), and
V
LCTH
= 0.05 mA x
R
LCTH
. The off-hook comparator
goes low when V
LCTH
crosses zero and then goes neg-
ative:
V
LCTH
= 0.05 mA x R
LCTH
+ V
DCOUT
= 0.05 x R
LCTH
– 0.125 V/mA x I
TR
R
LCTH
(k
) = 2.5 x I
TR
(mA)
12-2553.a (C)
Figure 30. Off-Hook Detection Circuit
DCR
25 k
±
30%
R1
R3
DCOUT
Rdc
113
500
V
DCOUT
--------------------
+
=
113
500
||
R
3
R
1
25 k
+
||
---------------------------------
+
=
DCR
25 k
±
30%
R1
R3
DCOUT
R2
–5 V
V
OH
6.5
20
||
R
2
R
1
25 k
||
+
||
R
3
||
---------------------------------------------
+
=
Rdc
113
500
||
R
3
R
1
25 k
+
||
-----------------------------------
+
=
R
L
----------------------------
I
L
2R
P
–
Rdc
–
=
R
L
ITR
R
P
R
P
PR
–
+
–
+
DCOUT
R
LCTH
LCTH
NLC
PT
–0.125 V/mA
0.05 mA
相关PDF资料 |
PDF描述 |
|---|---|
| ATTL7554BP-TR | L7554 Low-Power SLIC |
| ATTL7554P-TR | L7554 Low-Power SLIC |
| ATTL7554AP | LH1263 E&M Signaling Circuit |
| AU01Z | Fast-Recovery Rectifier Diodes |
| AU02Z | Fast-Recovery Rectifier Diodes |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ATTL7554BP-TR | 制造商:AGERE 制造商全称:AGERE 功能描述:L7554 Low-Power SLIC |
| ATTL7554P-TR | 制造商:AGERE 制造商全称:AGERE 功能描述:L7554 Low-Power SLIC |
| ATTL7556AAU | 制造商:未知厂家 制造商全称:未知厂家 功能描述:LH1263 E&M Signaling Circuit |
| ATTL7556AAU-TR | 制造商:AGERE 制造商全称:AGERE 功能描述:Low-Power SLICs with Battery Switch |
| ATTL7557AAU | 制造商:AGERE 制造商全称:AGERE 功能描述:Low-Power SLICs with Battery Switch |
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