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參數(shù)資料
| 型號(hào)： | MC33215FB |
| 廠商： | MOTOROLA INC |
| 元件分類： | 無繩電話/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 |
| 文件頁數(shù)： | 10/20頁 |
| 文件大?。?/td> | 456K |
| 代理商： | MC33215FB |
MC33215
10
MOTOROLA ANALOG IC DEVICE DATA
A. Maximum Available Current at V
CC
Figure 6. Available Current at V
CC
0
100
I
line
(mA)
0
3.5
C
V
I
line
(mA)
90
80
70
60
50
40
30
20
10
0
20
40
60
80
100
3.0
2.5
2.0
1.5
1.0
0.5
0
20
40
60
80
100
B. Voltage Drop to V
CC
I
VCC
/l
line
(%)
I
VCC(max) (mA)
V
CC
to VLS
I
VCC
at 98% of
I
VCC(max)
I
VCC
at 50% of
I
VCC(max)
V
CC
Open
m
For instance, at a line current of 20 mA a maximum of
15 mA of current is available at V
CC
. If all this current is
taken, V
CC
will be 1.7 V below VLN. When not all this current
is drawn from V
CC
, but for instance only 1.0 mA for biasing of
the loudspeaker amplifier, the voltage at V
CC
will be 1.2 V
below VLN. Although the measurements for Figure 6 are
done with R
REG1
= 365 k, the results are also globally valid
for other dc settings.
As can be seen from Figure 6, the voltage at V
CC
is limited
by the voltage at VLN minus 1.0 V. This means that the
voltage at V
CC
is limited by the external zener at VLN. If it is
necessary to limit the voltage at V
CC
in order to protect
peripheral circuits, a zener from V
CC
to Gnd can be added. If
the supply of the loudspeaker VLS is also connected to V
CC
,
it is advisable that V
CC
does not exceed 8.0 V.
The high efficiency of the V
CC
power supply contributes
to a high loudspeaker output power at moderate line
currents. More details on this can be found in the handsfree
operation paragraph.
HANDSET OPERATION
During handset operation, the MC33215 performs the
basic telephone functions for the handset microphone and
earpiece. It also enables DTMF transmission.
Handset Microphone Amplifier
The handset microphone is to be capacitively connected
to the circuit via the differential input HM1 and HM2. The
microphone signal is amplified by the HMIC amplifier and
modulates the line current by the injection of the signal into
the line driver. This transfer from the microphone inputs to the
line current is given as 15/(R
SLP
/11), which makes a total
transmit voltage gain A
HM
from the handset microphone
inputs to the line of:
Vline
VHM
With the typical application and Z
line
= 600
the transmit
gain calculates as 47 dB.
In case an electret microphone is used, it can be supplied
from the stabilized microphone supply point VMC of 1.75 V
properly biased with resistors R
HM1
and R
HM2
. This allows
the setmaker to use an electret microphone with poor supply
rejection to reduce total system costs. Since the transmit gain
A
HM
is fixed by the advised R
SLP
= 220
and the constraints
of set impedance and line impedance, the transmit gain is set
AHM
15
RSLP11
x
Zlinex Zset
Zline
Zset
by adjusting the sensitivity of the handset microphone by
adjusting the resistors R
HM1
and R
HM2
. It is not advised to
adjust the gain by including series resistors towards the Pins
HM1 and HM2.
A high pass filter is introduced by the coupling capacitors
C
HM1
and C
HM2
in combination with the input impedance. A
low pass filter can be created by putting capacitors in parallel
with the resistors R
HM1
and R
HM2
.
The transmit noise is measured as –72 dBmp with the
handset microphone inputs loaded with a capacitively
coupled 200
. In a real life application, the inputs will be
loaded with a microphone powered by VMC. Although VMC
is a stablized supply voltage, it will contain some noise which
can be coupled to the handset microphone inputs, especially
when a microphone with a poor supply rejection is used. An
additional RC filter on VMC can improve the noise figure, see
also the base microphone section.
Handset Earpiece Amplifier
The handset earpiece is to be capacitively connected to
the RXO output. Here, the receive signal is available which is
amplified from the line via the sidetone network and the R
x
and EAR amplifiers. The sidetone network attenuates the
receive signal from the line via the resistor divider composed
of R
SLB
and Z
bal
, see also the sidetone section. The
attenuation in the typical application by this network equals
24.6 dB. Then the signal from the sidetone network is
pre–amplified by the amplifier R
x
with a typical gain of 6.0 dB.
This amplifier also performs the AGC and MUTE functions,
see the related paragraphs. Finally, the signal is amplified by
the noninverting voltage amplifier EAR. The overall receive
gain A
RX
from the line to the earpiece output then follows as:
VRXO
Vline
ARX
ASTx ARXIx
1
RRXO
RGRX
With: A
ST
= Attenuation of the Sidetone Network
A
RXI
= Gain of the Pre–Amplifier R
x
For the typical application an overall gain from the line to
the earpiece is close to 0 dB.
The receive gain can be adjusted by adjusting the resistor
ratio R
RXO
over R
GRX
. However, R
RXO
also sets the
confidence tone level during dialing which leaves R
GRX
to be
chosen freely. A high pass filter is introduced by the coupling
capacitor C
RXI
together with the input impedance of the input
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相關(guān)代理商/技術(shù)參數(shù) |
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| 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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