參數(shù)資料
型號(hào)： MC33215FB
廠商： MOTOROLA INC
元件分類： 無(wú)繩電話/電話
英文描述： Telephone Line Interface and Speakerphone Circuit
中文描述： TELEPHONE SPEECH CKT, PQFP52
封裝： PLASTIC, TQFP-52
文件頁(yè)數(shù)： 8/20頁(yè)
文件大小： 456K
代理商： MC33215FB
MC33215
8
MOTOROLA ANALOG IC DEVICE DATA
DESCRIPTION OF THE CIRCUIT
Based on the typical application circuit as given in
Figure 18, the MC33215 will be described in three parts: line
driver and supplies, handset operation, and handsfree
operation. The data used refer to typical data of the
characteristics.
LINE DRIVER AND SUPPLIES
The line driver and supply part performs the ac and dc
telephone line termination and provides the necessary
supply points.
AC Set Impedance
The ac set impedance of the telephone as created by the
line driver and its external components can be approximated
with the equivalent circuit shown in Figure 2.
Figure 2. Equivalent of the AC impedance
Inductor
RREG1x CREGx
RSLP
11
Slope
RSLP
11
x
1
RREG1
RREG2
C
10 n
C
VDD
100
μ
Z
VDD
620
Z
bal
R
2.2 k
R
REG
∞
R
REG1
360 k
C
220 n
Slope
Inductor
With the component values of the typical application, the
inductor calculates as 1.6 H. Therefore, in the audio range of
300 Hz to 3400 Hz, the set impedance is mainly determined
by Z
VDD
. As a demonstration, the impedance matching or
Balance Return Loss BRL is shown in Figure 3.
100
40
B
f, FREQUENCY (Hz)
Figure 3. Balance Return Loss
35
30
25
20
15
10
5.0
0
1000
10000
The influence of the frequency dependent parasitic
components is seen for the lower frequencies (Inductor) and
the higher frequencies (C
VLN
) by a decreasing BRL value.
DC Set Impedance
The line current flowing towards the MC33215 application
is partly consumed by the circuitry connected to V
DD
while
the rest flows into Pin VLN. At Pin VLN, the current is split up
into a small part for biasing the internal line drive transistor
and into a large part for supplying the speakerphone. The
ratio between these two currents is fixed to 1:10. The dc set
impedance or dc setting of the telephone as created by the
line driver and its external components can be approximated
with the equivalent of a zener voltage plus a series resistor
according to:
Vzener
0.2 x
1
RREG1
RREG2
10
μ
A x RREG1
ILN
Iline– IVDD
Rslope
RSLP
11
x
1
RREG1
RREG2
With:
VLN
Vzener
ILN x Rslope
If R
REG2
is not mounted, the term between the brackets
becomes equal to 1.
With the values shown in the typical application and under
the assumption that I
VDD
= 1.0 mA, the above formulas can
be simplified to:
VLN
3.8 V
Iline– 1.0 mA
3.8 V
x 20
Ilinex 20
In the typical application this leads to a line voltage of 4.2 V
at 20 mA of line current with a slope of 20
. Adding a 1.5 V
voltage drop for the diode bridge and the interruptor, the dc
voltage at tip–ring will equal 5.7 V.
If the dc mask is to be adapted to a country specific
requirement, this can be done by adjusting the resistors
R
REG1
and R
REG2
, as a result, the zener voltage and the
slope are varied. It is not advised to change the resistor R
SLP
since this changes many parameters. The influence of R
REG1
and R
REG2
is shown in Figure 4.
Figure 4. Influence of R
REG1
and R
REG2
on the DC Mask
0
12
V
I
line
(mA)
10
8.0
6.0
4.0
2.0
0
20
40
60
80
100
.
R
REG1
= 470 k
R
REG2
= 220 k
R
REG1
= 365 k
R
REG2
= 220 k
R
REG1
= 470 k
R
REG2
= Infinite
R
REG1
= 365 k
R
REG2
= Infinite
As can be seen in Figure 4, for low line currents below
10 mA, the given dc mask relations are no longer valid. This
is the result of an automatic decrease of the current drawn
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC33218AP 制造商:Rochester Electronics LLC 功能描述: 制造商:Motorola Inc 功能描述: 制造商:MOTOROLA 功能描述:
MC33232D 功能描述:功率因數(shù)校正 IC Critical Mode PFC RoHS:否 制造商:Fairchild Semiconductor 開關(guān)頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
MC33232DG 功能描述:功率因數(shù)校正 IC Critical Mode PFC RoHS:否 制造商:Fairchild Semiconductor 開關(guān)頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
MC33232DR2 功能描述:功率因數(shù)校正 IC Critical Mode PFC RoHS:否 制造商:Fairchild Semiconductor 開關(guān)頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
MC33232DR2G 功能描述:功率因數(shù)校正 IC Critical Mode PFC RoHS:否 制造商:Fairchild Semiconductor 開關(guān)頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
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