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參數(shù)資料
| 型號(hào)： | MT8885 |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | Integrated DTMF Transceiver with Power Down and Adaptive Micro Interface(雙音多頻信號(hào)（DTMF）收發(fā)器（帶電源關(guān)閉和自適應(yīng)微接口）) |
| 中文描述： | 集成雙音多頻收發(fā)器的斷電和自適應(yīng)微型接口（雙音多頻信號(hào)（DTMF）的收發(fā)器（帶電源關(guān)閉和自適應(yīng)微接口）） |
| 文件頁(yè)數(shù)： | 3/25頁(yè) |
| 文件大?。?/td> | 190K |
| 代理商： | MT8885 |
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Preliminary Information
MT8885
4-53
Functional Description
The MT8885 Integrated DTMF Transceiver consists
of a high performance DTMF receiver with an
internal gain setting amplifier and a DTMF generator,
which employs a burst counter to synthesize precise
tone bursts and pauses. A call progress mode can
be selected so that frequencies within the specified
passband can be detected. The adaptive micro
interface allows various microcontrollers to access
the MT8885 internal registers.
Power-Down
The MT8885 provides enhanced power-down
functionality to facilitate minimization of supply
current consumption. DTMF transmitter and receiver
circuit blocks may be independently powered down
via register control. When asserted, the RxEN
control bit powers down all analog and digital
circuitry associated solely with the DTMF and Call
Progress receiver. The TOUT control bit is used to
disable the transmitter and put all circuitry
associated only with the DTMF transmitter in power-
down mode. With the TOUT control bit asserted, the
TONE output pin is held in a high impedance
(floating) state. When both power-down control bits
are asserted, circuits utilized by both the DTMF
transmitter and receiver are also powered down.
This power-down control disables the crystal
oscillators, and the VRef generator. In addition, the
IRQ , TONE output and DATA pins are held in a high
impedance state. Finally, the whole device is put in
a power-down state when the PWDN pin is asserted.
Input Configuration
The input arrangement of the MT8885 provides a
differential-input operational amplifier as well as a
bias source (V
Ref
), which is used to bias the inputs at
V
DD
/2. Provision is made for connection of a
feedback resistor to the op-amp output (GS) for gain
adjustment. In a single-ended configuration, the
input pins are connected as shown in Figure 3.
Figure 4 shows the necessary connections for a
differential input configuration.
Receiver Section
Separation of the low and high group tones is
achieved by applying the DTMF signal to the inputs
of two sixth-order switched capacitor bandpass
filters, the bandwidths of which correspond to the low
and high group frequencies (see Table 1). The filters
also incorporate notches at 350 Hz and 440 Hz for
exceptional dial tone rejection. Each filter output is
followed by a single order switched capacitor filter
section, which smooths the signals prior to limiting.
Limiting is performed by high-gain comparators
which are provided with hysteresis to prevent
detection of unwanted low-level signals. The outputs
of the comparators provide full rail logic swings at the
frequencies of the incoming DTMF signals.
Figure 3 - Single-Ended Input Configuration
Figure 4 - Differential Input Configuration
C
R
IN
R
F
IN+
IN-
GS
V
Ref
VOLTAGE GAIN
(A
V
) = R
F
/ R
IN
MT8885
C1
C2
R1
R2
R3
R4
R5
IN+
IN-
GS
V
Ref
DIFFERENTIAL INPUT AMPLIFIER
C1 = C2 = 10 nF
R1 = R4 = R5 = 100 k
R2 = 60k
, R3 = 37.5 k
R3 = (R2R5)/(R2 + R5)
VOLTAGE GAIN
(A
V
diff) - R5/R1
INPUT IMPEDANCE
(Z
IN
diff) = 2
R1
2
+ (1/
ω
C)
2
MT8885
24
28
V
DD
NC
Positive power supply (5V typ.).
No Connection.
8,9
17
3,5,
10,11
16,
20,
25
Pin Description
Pin #
Name
Description
24
28
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MT8888CE-1 | Integrated DTMFTransceiver with Intel Micro Interface |
| MT8888CN-1 | CB 3C 3#16S SKT RECP WALL |
| MT8888CS-1 | Integrated DTMFTransceiver with Intel Micro Interface |
| MT8888C | Integrated DTMFTransceiver with Intel Micro Interface |
| MT8888CC | Integrated DTMFTransceiver with Intel Micro Interface |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MT8885AE | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Integrated DTMFTransceiver with Power Down & Adaptive Micro Interface |
| MT8885AE1 | 制造商:Microsemi Corporation 功能描述:DTMF TXRX 3.58MHZ CMOS 5V 24PDIP - Rail/Tube 制造商:MICROSEMI CONSUMER MEDICAL PRODUCT GROUP 功能描述:IC TXRX DTMF 20PDIP 制造商:Microsemi Corporation 功能描述:IC TXRX DTMF 20PDIP |
| MT8885AN | 制造商:Microsemi Corporation 功能描述:DTMF TXRX 3.58MHZ CMOS 5V 24SSOP - Rail/Tube |
| MT8885AN1 | 制造商:Microsemi Corporation 功能描述:DTMF TXRX 3.58MHZ CMOS 5V 24SSOP - Rail/Tube |
| MT8885ANR | 制造商:Microsemi Corporation 功能描述: |
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