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參數(shù)資料
| 型號： | L3281AB |
| 廠商： | 意法半導(dǎo)體 |
| 英文描述： | LOW VOLTAGE TELEPHONE SPEECH CIRCUITS |
| 中文描述： | 低壓電話語音電路 |
| 文件頁數(shù)： | 6/10頁 |
| 文件大?。?/td> | 170K |
| 代理商： | L3281AB |
DCCHARACTERISTIC
The fig.5 shows the equivalentsimplified circuit of
the DC regulator that provides to give the oppor-
tuneDC impedanceZdc.
VL
=
Idc
Z4
RB
(
RA
+
RB
)
+
VD
+
VR1
VL
=
(
Idc
Z4
)
RA
RB
+
1
+
VD
+
VR1
sinceRA = RB
VL
=
(
Idc
Z4
2
)
+
VD
+
VR1
When IL 18 mA and considering neglectible the
VD + VR1 variation versus line current :
ZDC
=
VL
Idc
=
2
Z4
At IL = 6.5 mA no current flows through Z4 but
only in the rest of the circuit for internal biasing
(Io;Ia). The bias current Io is fixed by the resistor
R2. The line voltage in thiscase is :
VL = Ia RA + VR1 = 1.6 V
The Fig.6 shows the DC characteristic (voltage
between pin 12 and pin 3 versus line current).
The device own an equivalent zener voltage at
pin 5 that can be used as supply voltage for elec-
tret microphone (see Block Diagram).
The value of the resistor R2 and the capacitor C2
should be chosen in order to not affect the AC
line inpedance. The Fig.7 shows the zener
equivalent.
The zener voltage will be:
Vz
=
70K
13.6K
+
1
Vbe
It is possible to supply 1mA to the electrete volt-
age if VL > (1mA + Iz)
Rz + Vz
Figure5:
Equivalent Simplified Circuit
Figure 6:
LowVoltage SpeechCircuit.
Figure 7:
ZenerEquivalent.
L3281
6/10
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| L3281AD1 | LOW VOLTAGE TELEPHONE SPEECH CIRCUITS |
| L3845 | TRUNK INTERFACE |
| L3845B | TRUNK INTERFACE |
| L3845D | TRUNK INTERFACE |
| L387 | VERY LOW DROP 5V REGULATOR WITH RESET |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| L3281AD1 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:LOW VOLTAGE TELEPHONE SPEECH CIRCUITS |
| L-32AEIR1C | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:RECEIVER MODULE |
| L-32AOPT1D1 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:RECEIVER MODULE |
| L32ART | 制造商:Burndy 功能描述:L-DIE |
| L32-B0-24-620-46A-C3 | 制造商:Carling Technologies 功能描述: |
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