- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄2012 > MC34118DW (Freescale Semiconductor)IC VOICE SWITCH SPKPHONE 28-SOIC PDF資料下載
參數(shù)資料
| 型號(hào)： | MC34118DW |
| 廠商： | Freescale Semiconductor |
| 文件頁數(shù)： | 21/22頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC VOICE SWITCH SPKPHONE 28-SOIC |
| 標(biāo)準(zhǔn)包裝： | 26 |
| 功能： | 語音切換式揚(yáng)聲電話 |
| 電路數(shù)： | 1 |
| 電源電壓： | 3.5 V ~ 6.5 V |
| 電流 - 電源： | 5.5mA |
| 工作溫度： | -20°C ~ 60°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 28-SOIC（0.295"，7.50mm 寬） |
| 供應(yīng)商設(shè)備封裝： | 28-SOIC W |
| 包裝： | 管件 |
| 包括： | 背景噪聲監(jiān)視器，芯片禁用，撥號(hào)音調(diào)檢測(cè)器，驅(qū)動(dòng)器放大器，電平檢測(cè)器，麥克風(fēng)放大器，靜音 |
MC34118
MOTOROLA
8
+
--
+
--
+
--
+
--
+
--
+
CPR
(CPT)
VCC
100 k
TO ATTENUATOR
CONTROL BLOCK
C2
(C1)
NOTE: External component values are
applicaton dependent.
BACKGROUND
NOISE MONITOR
47 F
36 mV
56 k
COMPARATOR
33 k
VB
C4
(C3)
LEVEL DETECTOR
TLO1
(RLO2)
2.0 F
4.0
A
350
VB
4.0
A
VB
Figure 4. Level Detectors
5.1 k
350
SIGNAL
INPUT
SIGNAL
INPUT
RLO1
(TLO2)
2.0 F
0.1 F
5.1 k
TLI1
(RLI2)
RLI1
(TLI2)
speaker amplifier. On the transmit side, one level detector
(TLI2) is at the output of the microphone amplifier, while the
other (TLI1) is at the hybrid output. Outputs RLO1 and TLO1
feed a comparator, the output of which goes to the Attenuator
Control Block. Likewise, outputs RLO2 and TLO2 feed a
second comparator which also goes to the Attenuator Con-
trol Block. The truth table for the effects of the level detectors
on the Control Block is given in the section describing the
Control Block.
BACKGROUND NOISE MONITORS
The purpose of the background noise monitors is to distin-
guish speech (which consists of bursts) from background
noise (a relatively constant signal level). There are two back-
ground noise monitors — one for the receive path and one
for the transmit path. Referring to Figure 4, the receive back-
ground noise monitor is operated on by the RLI1--RLO1 level
detector, while the transmit background noise monitor is op-
erated on by the TLI2--TLO2 level detector. They monitor the
background noise by storing a dc voltage representative of
the respective noise levels in capacitors at CPR and CPT.
The voltages at these pins have slow rise times (determined
by the external RC), but fast decay times. If the signal at RLI1
(or TLI2) changes slowly, the voltage at CPR (or CPT) will
remain more positive than the voltage at the non--inverting
input of the monitor’s output comparator. When speech is
present, the voltage on the noninverting input of the com-
parator will rise quicker than the voltage at the inverting input
(due to the burst characteristic of speech), causing its output
to change. This output is sensed by the Attenuator Control
Block.
The 36 mV offset at the comparator’s input keeps the
comparator from changing state unless the speech level ex-
ceeds the background noise by ≈4.0 dB. The time constant
of the external RC (≈4.7 seconds) determines the response
time to background noise variations.
VOLUME CONTROL
The volume control input at VLC (Pin 13) is sensed as a
voltage with respect to VB. The volume control affects the
attenuators only in the receive mode. It has no effect in the
idle or transmit modes.
When in the receive mode, the gain of the receive attenua-
tor will be + 6.0 dB, and the gain of the transmit attenuator
will be -- 46 dB only when VLC is equal to VB.As VLC is re-
duced below VB, the gain of the receive attenuator is reduced
(see Figure 14), and the gain of the transmit attenuator is
increased such that their sum remains constant. Changing
the voltage at VLC changes the voltage at CT (see the At-
tenuator Control Block section), which in turn controls the
attenuators.
The volume control setting does not affect the maximum
attenuator input signal at which noticeable distortion occurs.
The bias current at VLC is typically 60 nA out of the pin,
and does not vary significantly with the VLC voltage or with
VCC.
DIAL TONE DETECTOR
The dial tone detector is a comparator with one side con-
nected to the receive input (RXI) and the other input con-
nectedtoVB with a 15 mV offset (see Figure 5). If the circuit
is in the receive mode, and the incoming signal is greater
than 15 mV (10 mVrms), the comparator’s output will
change, disabling the receive idle mode. The receive attenu-
ator will then be at a setting determined solely by the volume
control.
The purpose of this circuit is to prevent the dial tone
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MC44C401LACR2 | IC STEREO ENCODER MTS 32-LQFP |
| MC44C402ACR2 | IC STEREO ENCODER MTS 32-LQFP |
| MC92603VF | IC TXRX ETH QUAD GIG 256-MAPBGA |
| MC92604VM | IC ETH TXRX DUAL GIG 196-MAPBGA |
| MC92604ZT | IC TXRX ETH DUAL GIG 196-MAPBGA |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MC34118-E28-T | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:VOICE SWITCHED SPEAKER-PHONE CIRCUIT |
| MC34118EG | 制造商:Rochester Electronics LLC 功能描述: |
| MC34118G-D28-T | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:VOICE SWITCHED SPEAKER-PHONE CIRCUIT |
| MC34118G-E28-T | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:VOICE SWITCHED SPEAKER-PHONE CIRCUIT |
| MC34118G-S28-R | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:VOICE SWITCHED SPEAKER-PHONE CIRCUIT |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。