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PDF MC145442 Data sheet ( Hoja de datos )
| Número de pieza | MC145442 | |
| Descripción | Single-Chip 300-Baud Modem | |
| Fabricantes | Motorola Semiconductors | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de MC145442 (archivo pdf) en la parte inferior de esta página. Total 12 Páginas | ||
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MOTOROLA
SEMICONDUCTOR TECHNICAL DATA
Single-Chip 300-Baud Modem
The MC145442 and MC145443 silicon–gate CMOS single–chip low–speed
modems contain a complete frequency shift keying (FSK) modulator, demodu-
lator, and filter. These devices are with CCITT V.21 (MC145442) and Bell 103
(MC145443) specifications. Both devices provide full–duplex or half–duplex
300–baud data communication over a pair of telephone lines. They also include
a carrier detect circuit for the demodulator section and a duplexer circuit for
direct operation on a telephone line through a simple transformer.
• MC145442 Compatible with CCITT V.21
• MC145443 Compatible with Bell 103
• Low–Band and High–Band Band–Pass Filters On–Chip
• Simplex, Half–Duplex, and Full–Duplex Operation
• Originate and Answer Mode
• Analog Loopback Configuration for Self Test
• Hybrid Network Function On–Chip
• Carrier Detect Circuit On–Chip
• Adjustable Transmit Level and CD Delay Timing
• On–Chip Crystal Oscillator (3.579 MHz)
• Single + 5 V Power Supply Operation
• Internal Mid–Supply Generator
• Power–Down Mode
• Pin Compatible with MM74HC943
• Capable of Driving – 9 dBm into a 600 Ω Load
Order this document
by MC145442/D
MC145442
MC145443
20
1
P SUFFIX
PLASTIC DIP
CASE 738
20
1
DW SUFFIX
SOG PACKAGE
CASE 751D
ORDERING INFORMATION
MC145442P Plastic DIP
MC145443P Plastic DIP
MC145442DW SOG Package
MC145443DW SOG Package
PIN ASSIGNMENT
DSI 1
LB 2
CD 3
CDT 4
RxD 5
VDD 6
CDA 7
Xout 8
Xin 9
FB 10
20 TLA
19 VAG
18 Exl
17 TxA
16 RxA1
15 RxA2
14 SQT
13 MODE
12 VSS
11 TxD
REV 1
8/95
©MOMoTtoOroRla,OInLc.A1995
MC145442•MC145443
1
1 page  
RxA2, RxA1
Receive Carrier (Pins 15, 16)
The receive carrier is the FSK input to the demodulator
through the receive band–pass filter. RxA1 is the non–invert-
ing input and RxA2 is the inverting input of the receive hybrid
(duplexer) operational amplifier.
LB
Analog Loopback (Pin 2)
When a high level is applied to this pin (SQT must be low),
the analog loopback test is enabled. The analog loopback
test connects the TxA pin to the RxA2 pin and the RxA1 to
analog ground. In loopback, the demodulator frequencies
are switched to the modulation frequencies for the selected
mode. (See Tables 1 and 2 and Figures 4c and 4d.)
When LB is connected to analog ground (VAG), the modu-
lator generates an echo cancellation tone of 2100 Hz for
MC145442 CCITT V.21 and 2225 Hz for MC145443 Bell 103
systems. For normal operation, this pin should be at a logic
low level (VSS).
The power–down mode is enabled when both LB and SQT
are connected to a logic high level (see Table 2).
MODE
Pin 13
1
0
X
X
X
X
X
Table 2. Functional Table
SQT
Pin 14
LB
Pin 2
Operating Mode
0 0 Originate Mode
0 0 Answer Mode
0 VAG (VDD/2) Echo Tone
0 1 Analog Loopback
1 0 Squelch Mode
1 VAG (VDD/2) Squelch Mode
1 1 Power Down
MODE
Mode (Pin 13)
This input selects the pair of transmit and frequencies
used during modulation and demodulation. When a logic
high level is placed on this input, originate (Bell) or channel 1
(CCITT) is selected. When a low level is placed on this input,
answer (Bell) or channel 2 (CCITT) is selected. (See
Tables 1 and 2 and Figure 4.)
CDT
Carrier Detect Timing (Pin 4)
A capacitor on this pin to VSS sets the amount of time the
carrier must be present before CD goes low (see Applica-
tions Information for the capacitor values).
CD
Carrier Detect Output (Pin 3)
This output is used to indicate when a carrier has been
sensed by the carrier detect circuit. This output goes to a
logic low level when a valid signal above the maximum
threshold level (defined by CDA, Pin 7) is maintained on the
input to the hybrid circuit longer then the response (defined
by CDT, Pin 4). This pin is held at the logic low level until the
signal falls below the maximum threshold level for longer
than the turn off time. (See Applications Information and
Figure 5.)
CDA
Carrier Detect Adjust (Pin 7)
An external voltage may be applied to this pin to adjust the
carrier detect threshold. The threshold hysteresis is internally
fixed at 3 dB (see Applications Information).
Xout, Xin
Crystal Oscillator (Pins 8, 9)
A crystal reference oscillator is formed when a 3.579 MHz
crystal is connected between these two pins. Xout (Pin 8) is
the output of the oscillator circuit, and Xin (Pin 9) is the input
to the oscillator circuit. When using an external clock, apply
the clock to the Xin (Pin 9) pin and leave Xout (Pin 8) open. An
internal 10 MΩ resistor and internal capacitors, typically
10 pF on Xin and 16 pF on Xout, allow the crystal to be con-
nected without any other external components. Printed cir-
cuit board layout should keep external stray capacitance to a
minimum.
FB
Filter Bias (Pin 10)
This is the negative input to the ac amplifier. In normal op-
eration, this pin is connected to analog ground through a
0.1 µF bypass capacitor in order to cancel the input offset
voltage of the limiter. It has a nominal input impedance of
16 kΩ. (see Figure 3).
SQT
Transmit Squelch (Pin 14)
When this input pin is at a logic high level, the modulator is
disabled. The line driver remains active if LB is at a logic low
level (see Table 2) .
When both LB and SQT are connected to a logic high
level, see Table 2, the entire chip is in a power down state
and all circuitry except the crystal oscillator is disabled. Total
power supply current decreases from 10 mA (Max) to 300 µA
(Max).
FROM
BAND–PASS
FILTER
+
–
TO
CARRIER DETECT CIRCUIT
AND DEMODULATOR
490 kΩ
16 kΩ
10 FB
0.1 µF
Figure 3. ac Amplifier Circuit
MOTOROLA
MC145442•MC145443
5
5 Page 
-A-
20
1
-T-
SEATING
PLANE
E
GF
PACKAGE DIMENSIONS
P SUFFIX
PLASTIC DIP
CASE 738–03
11
B
10
C
K
N
D 20 PL
0.25 (0.010) M T A M
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION L TO CENTER OF LEAD WHEN
FORMED PARALLEL.
4. DIMENSION B DOES NOT INCLUDE MOLD
L FLASH.
M
J 20 PL
0.25 (0.010) M T B M
INCHES
MILLIMETERS
DIM MIN MAX MIN MAX
A 1.010 1.070 25.66 27.17
B 0.240 0.260 6.10 6.60
C 0.150 0.180 3.81 4.57
D 0.015 0.022 0.39 0.55
E 0.050 BSC
1.27 BSC
F 0.050 0.070 1.27 1.77
G 0.100 BSC
2.54 BSC
J 0.008 0.015 0.21 0.38
K 0.110 0.140 2.80 3.55
L 0.300 BSC
7.62 BSC
M 0° 15° 0° 15°
N 0.020 0.040 0.51 1.01
DW SUFFIX
SOG PACKAGE
CASE 751D–04
–A–
20 11
–B– 10X P
0.010 (0.25) M B M
1 10
20X D
0.010 (0.25) M T A S B S
J
F
18X G
C
–T–
SEATING
PLANE
K
M
R X 45_
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSIONS A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.150
(0.006) PER SIDE.
5. DIMENSION D DOES NOT INCLUDE
DAMBAR PROTRUSION. ALLOWABLE
DAMBAR PROTRUSION SHALL BE 0.13
(0.005) TOTAL IN EXCESS OF D DIMENSION
AT MAXIMUM MATERIAL CONDITION.
MILLIMETERS
INCHES
DIM MIN MAX MIN MAX
A 12.65 12.95 0.499 0.510
B 7.40 7.60 0.292 0.299
C 2.35 2.65 0.093 0.104
D 0.35 0.49 0.014 0.019
F 0.50 0.90 0.020 0.035
G 1.27 BSC
0.050 BSC
J 0.25 0.32 0.010 0.012
K 0.10 0.25 0.004 0.009
M 0_ 7_ 0_ 7_
P 10.05 10.55 0.395 0.415
R 0.25 0.75 0.010 0.029
MOTOROLA
MC145442•MC145443
11
11 Page | ||
| Páginas | Total 12 Páginas | |
| PDF Descargar | [ Datasheet MC145442.PDF ] | |
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