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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)： | 9/20頁 |
| 文件大?。?/td> | 456K |
| 代理商： | MC33215FB |
MC33215
9
MOTOROLA ANALOG IC DEVICE DATA
from Pin REG by the internal circuit (the 10
μ
A term in the
formulas). This built–in feature drops the line voltage and
therefore enables parallel operation.
The voltage over the line driver has to be limited to 12 V to
protect the device. A zener of 11 V at VLN is therefore the
maximum advised.
V
DD
Supply
The internal circuitry for the line driver and handset
interface is powered via V
DD
. This pin may also be used to
power peripherals like a dialer or microcontroller. The voltage
at V
DD
is not internally regulated and is a direct result of the
line voltage setting and the current consumption at V
DD
internally (I
VDD
) and externally (I
PER
). It follows that:
VDD
For correct operation, it must be ensured that V
DD
is
biased at 1.8 V higher than SLP. This translates to a
maximum allowable voltage drop across Z
VDD
of
V
zener
– 1.8 V. In the typical application, this results in a
maximum allowable current consumption by the peripherals
of 2.0 mA.
VLN – IVDD
IPER
x Rset
VMC Supply
At VMC, a stabilized voltage of 1.75 V is available for
powering the handset microphone. Due to this stabilized
supply, microphones with a low supply rejection can be used
which reduces system costs. In order to support the parallel
operation of the telephone set, the voltage at VMC will be
maintained even at very low line currents down to 4.0 mA.
Under normal supply conditions of line currents of 20 mA
and above, the supply VMC is able to deliver a guaranteed
minimum of 1.0 mA. However, for lower line currents, the
supply capability of VMC will decrease.
Figure 5. VMC Under Different Microphone Loads
1.8
0
V
I
VMC
(mA)
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
I
= 4.0 mA
2.7 k VMC–VHF
I
line
= 20 mA
I
line
= 4.0 mA
If, during parallel operation, a high current is required from
VMC, a 2.7 k resistor between VMC and VHF can be applied.
In Figure 5, the VMC voltage under different microphone
currents, is shown.
VHF Supply
VHF is a stabilized supply which powers the internal
duplex controller part of the MC33215, and which is also
meant to power the base microphone or other peripherals.
The base microphone however, can also be connected to
VMC, which is preferred in case of microphones with a poor
supply rejection. Another possibility is to create an additional
filter at VHF, like is shown in the typical application. The
supply capability of VHF is guaranteed as 2.0 mA for line
currents of 20 mA and greater.
Since in parallel operation not enough line current is
available to power a loudspeaker and thus having a
speakerphone working, the current internally supplied to VHF
is cut around 10 mA of line current to save current for the
handset operated part. A small hysteresis is built in to avoid
system oscillations.
When the current to VHF is cut, the voltage at VHF will
drop rapidly due to the internal consumption of 1.4 mA and
the consumption of the peripherals. When VHF drops below
2.0 V, the device internally switches to the handset mode,
neglecting the state of the speakerphone select Pin SPS.
In case an application contains a battery pack or if it is
mains supplied, speakerphone operation becomes possible
under all line current conditions. In order to avoid switch–over
to handset operation below the 10 mA, VHF has to be
supplied by this additional power source and preferably kept
above 2.4 V.
V
CC
Supply
At V
CC
the major part of the line current is available for
powering the loudspeaker amplifier and peripheral circuitry.
This supply pin should be looked at as a current source since
the voltage on V
CC
is not stabilized and depends on the
instantaneous line voltage and the current to and consumed
from V
CC
.
The maximum portion of the line current which is available
at V
CC
is given by the following relation:
10
This formula is valid when the voltage drop from VLN to
V
CC
is sufficient for the current splitter to conduct all this
current to V
CC
. When the drop is not sufficient, the current
source saturates and the surplus of current is conducted to
the power ground PGD to avoid distortion in the line driver. In
fact, when no current is drawn from V
CC
, the voltage at V
CC
will increase until the current splitter is in balance. In Figure 6
this behavior is depicted.
IVCC
Iline– IVDD
– IVMC– IVHF
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|---|---|
| MC33219ADW | VOICE SWITCHED SPEAKERPHONE CIRCUIT |
| MC33219AP | VOICE SWITCHED SPEAKERPHONE CIRCUIT |
| MC33290D | ISO SERIAL LINK INTERFACE |
| MC33290 | ISO SERIAL LINK INTERFACE |
| MC33290DR2 | ISO SERIAL LINK INTERFACE |
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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