- 您現(xiàn)在的位置：買(mǎi)賣(mài)IC網(wǎng) > PDF目錄369899 > MC145444 (Motorola, Inc.) Single-Chip 300-Baud Modem PDF資料下載
參數(shù)資料
| 型號(hào)： | MC145444 |
| 廠商： | Motorola, Inc. |
| 英文描述： | Single-Chip 300-Baud Modem |
| 中文描述： | 單芯片300波特調(diào)制解調(diào)器 |
| 文件頁(yè)數(shù)： | 6/12頁(yè) |
| 文件大?。?/td> | 161K |
| 代理商： | MC145444 |
MC145444
6
MOTOROLA
TxA2
Inverting Transmit Analog Carrier Output (Pin 17)
This pin is the line driver inverting output. The signal is
equal in magnitude, but 180
°
out of phase with the TxA1
(refer to TxA1).
RxA
Receive Signal Input (Pin 19)
This pin is the receive signal input. The pin has an input
impedance of 50 k
(min).
RxGC
Receive Gain Adjust (Pin 20)
This pin is used to adjust the receive buffer gain. To adjust
the gain, the signal from the RxBO through a divider is added
as a feedback. This pin may be held open when the gain
adjustment is not needed.
RxBO
Receiver Buffer Output (Pin 1)
This pin is the receive buffer output.
DSI
Driver Summing Input (Pin 16)
This pin is the inverting input of the line driver. An external
signal is transmitted through an external series resistor RDSI.
The differential gain GDSI = (VTXA1 – VTXA2)/VDSI is deter-
mined by the following equation.
GDSI = – 2Rf / RDSI, Rf
≈
20 k
DSI should be left open when not used.
CDA
Carrier Detect Level/CPTD Level Control (Pin 4)
The carrier/call progress tone detect level is programmed
with a CDA pin voltage.
When this pin is held open, the CDA voltage is set to
1.2 V with an internal divider. The detect level is set at
– 44 dBm (typ) for off to on, and – 47 dBm (typ) for on to off.
The minimum hysteresis is 2 dB. This pin has a very high
input impedance so it should be connected to GND with a
0.1
μ
F capacitor to keep it well regulated. An external voltage
may be applied to this pin to adjust the carrier detect
threshold. The following equations may be used to find the
CDA voltage required for a given threshold voltage.
VCDA = 245
×
Von
VCDA = 347
×
Voff
FTLC
Filter Test (Pin 2)
This pin is a high–impedance filter output. It may be used
to check the receive filter. This pin also may be used as a
demodulator input. In normal operation, this pin is connected
to the GNDA through a 0.1
μ
F bypass capacitor. This pin
handles very small signals so care must be used with the
capacitor’s wiring.
TLA
Transmit Carrier Level Adjust (Pin 6)
This pin is used to adjust the transmit carrier level that is
determined by the value of the resistor (RTLA) connected
between this pin and GND. The maximum transmit level is
obtained when this pin is connected to GND (RTLA = 0).
SERIAL INTERFACE
The following six functions are set up with the 15–bit serial
data.
T3
T2
T1
T0
CD1
CD0
A2
A1
A0
TONE FREQUENCY
:
CARRIER DETECT TIME
:
CHANNEL
:
SQ
TRANSMIT SQUELCH
:
FUNCTION MODE
:
TRANSMIT ATTENUATOR
:
CH
A3
M2
M1
M0
Figure 3 presents the 15–bit serial data timing, starting
with the carrier detect time, CD1, followed by the channel,
the tone frequency, the transmit squelch, the transmit attenu-
ator, and the function mode. This data is loaded into the inter-
nal shift register at the rising edge of the SCK signal and
latched at the falling edge of the ENB signal.
FUNCTION MODE
Modes are selected from the following 3–bit data (M2 –
M0, see Table 1).
Table 1. Function Mode Truth Table
M2
M1
M0
Function Mode
0
0
0
FSK
0
0
1
Analog Loopback
0
1
0
CPTD
0
1
1
Answer Tone
1
0
0
DTMF
1
0
1
Single Tone
1
1
0
Power–Down 1
1
1
1
Power–Down 2
The following paragraphs describe each function. Table 2
presents each output status.
FSK Mode
The transmitter and the receiver work as a FSK modula-
tor/demodulator. The SD pin output is the carrier’s detect
signal.
Analog Loopback Mode
TxA1 connects to the receiver internally and FSK signals
are demodulated. The frequency of the receiver is set up with
the same frequency as the transmitter. The SD pin output is
the carrier detect signal. An IC self test is supported with this
function.
CPTD Mode
The receiver detects a 400 Hz call progress tone. The
detect signal comes from the SD pin. The transmitter is
disabled.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MC145444P | Single-Chip 300-Baud Modem |
| MC145446AFW | Single-Chip 300-Baud Modem with DTMF Transceiver |
| MC145446A | Single-Chip 300-Baud Modem with DTMF Transceiver |
| MC145446 | Single-Chip 300-Baud Modem with DTMF Transceiver |
| MC145447DW | Calling Line Identification(CLID) Receiver with Ring Detector |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MC145446AFW | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Motorola Inc 功能描述: 制造商:MOTOROLA 功能描述: |
| MC145447DW | 制造商:Motorola Inc 功能描述:CALLER NUMBER ID CIRCUIT, 16 Pin, Plastic, SOP |
| MC145447DWR2 | 制造商:Motorola Inc 功能描述:TELEPHONE MULTIFUNCTION CKT, 16 Pin Plastic SOP |
| MC145447P | 制造商:Motorola Inc 功能描述: |
| MC145475DW | 制造商:Motorola Inc 功能描述:DATACOM, ISDN CONTROLLER, PDSO28 |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。