Single-Chip Modem. 73K212AL Datasheet

73K212AL Modem. Datasheet pdf. Equivalent

Part 73K212AL
Description Single-Chip Modem
Feature DESCRIPTION The 73K212AL is a highly integrated single-chip modem IC which provides the functions ne.
Manufacture TDK
Datasheet
Download 73K212AL Datasheet



73K212AL
DESCRIPTION
The 73K212AL is a highly integrated single-chip
modem IC which provides the functions needed to
construct a typical Bell 212A full-duplex modem.
Using an advanced CMOS process that integrates
analog, digital and switched-capacitor filter functions
on a single substrate, the 73K212AL offers excellent
performance and a high level of functional
integration in a single 28-pin DIP or PLCC package.
The 73K212AL operates from a single +5V supply.
The 73K212AL is a new version replacing the
73K212L. The 73K212AL should be specified for all
new designs.
The 73K212AL includes the DPSK and FSK
modulator/demodulator functions, call progress and
handshake tone monitor test modes and a DTMF
dialer. This device supports all Bell 212A modes of
operation allowing both synchronous and
asychronous communications.
Test features such as analog loop, digital loop, and
remote digital loopback are provided. Internal
pattern generators are also included for self-testing.
The 73K212AL is designed to appear to the systems
designer as a microprocessor peripheral, and will
easily interface with popular one-chip micro-
processors (80C51 typical) for control of
(continued)
73K212AL
Bell 212A/103
Single-Chip Modem
FEATURES
January 1999
One-chip Bell 212A and 103 standard compatible
modem data pump
Full-duplex operation at 0-300 bit/s (FSK) or
1200 bit/s (DPSK)
Pin and software compatible with other TDK
Semiconductor Corporation K-Series 1-chip
modems
Interfaces directly with standard microprocessors
(8048, 80C51 typical)
Serial port for data transfer
Both synchronous and asynchronous modes of
operation
Call progress, carrier, precise answer tone and
long loop detectors
DTMF generators
Test modes available: ALB, DL, RDL, Mark, Space,
Alternating bit patterns
Precise automatic gain control allows 45 dB
dynamic range
CMOS technology for low power consumption
using 60 mW @ 5V
Single +5V supply
BLOCK DIAGRAM
AD0-AD7
DATA
BUS
BUFFER
5'
:5
ALE
&6
RESET
,17
TXD
RXD
READ
WRITE
CONTROL
LOGIC
STATUS
AND
CONTROL
LOGIC
8-BIT
BUS
FOR
CONTROL
AND
STATUS
SERIAL
PORT
FOR
DATA
DIGITAL
PROCESSING
TESTS:
ALB, DLB
RDLB
PATTERNS
CLOCK
GENERATOR
FSK
MODULATOR/
DEMODULATOR
PSK
MODULATOR/
DEMODULATOR
SMART
DIALING
&
DETECT
FUNCTIONS
POWER
DTMF &
TONE
GENERATORS
TRANSMIT
FILTER
RECEIVE
FILTER
TXA
RXA



73K212AL
73K212AL
Bell 212A/103
Single-Chip Modem
DESCRIPTION (continued)
modem functions through its 8-bit multiplexed
address/data bus or serial control bus. An ALE
control line simplifies address demultiplexing. Data
communications occurs through a separate serial
port only.
The 73K212AL is ideal for use in either free standing
or integral system modem products where full-
duplex 1200 bit/s data communications over the 2-
wire switched telephone network is desired. Its high
functionality, low power consumption and efficient
packaging simplify design requirements and
increase system reliability. A complete modem
requires only the addition of the phone line interface,
a control microprocessor, and RS-232 level
converter for a typical system. The 73K212AL is part
of TDK Semiconductor’s K-Series family of pin and
function compatible single-chip modem products.
These devices allow systems to be configured for
higher speeds and Bell or CCITT operation with only
a single component change.
OPERATION
ASYNCHRONOUS MODE
Data transmission for the DPSK mode requires that
data ultimately be transmitted in a synchronous
fashion. The 73K212AL includes ASYNC/SYNC and
SYNC/ASYNC converters which delete or insert stop
bits in order to transmit data within a 0.01% rate. In
asynchronous mode the serial data comes from the
TXD pin into the ASYNC/SYNC converter. The
ASYNC/SYNC converter accepts the data provided
on the TXD pin which normally must be 1200 bit/s
+1.0%, - 2.5%. The rate converter will then insert or
delete stop bits in order to output a signal which is
1200 bit/s ± .01% (±0.01% is the required
synchronous data rate accuracy).
The serial data stream from the ASYNC/SYNC
converter is passed through the data scrambler and
onto the analog modulator. The data scrambler can
be bypassed under processor control when
unscrambled data must be transmitted. The
ASYNC/SYNC rate converter and the data
scrambler are bypassed in all FSK modes. If serial
input data contains a break signal through one
character (including start and stop bits) the break will
be extended to at least 2 times N + 3 bits long
(where N is the number of transmitted
bits/character).
Serial data from the demodulator is passed first
through the data descrambler and then through the
SYNC/ASYNC rate converter. The SYNC/ASYNC
converter will reinsert any deleted stop bits and
transmit output data at an intra-character rate (bit-to-
bit timing) of no greater than 1219 bit/s. An incoming
break signal (low through two characters) will be
passed through without incorrectly inserting a stop bit.
SYNCHRONOUS MODE
The Bell 212A standard defines synchronous
operation only at 1200 bit/s. Operation is similar to
that of the asynchronous mode except that data
must be synchronized to a provided clock and no
variation in data transfer rate is allowable. Serial
input data appearing at TXD must be valid on the
rising edge of TXCLK.
TXCLK is an internally derived 1200 Hz signal in
internal mode and is connected internally to the
RXCLK pin in slave mode. Receive data at the RXD
pin is clocked out on the falling edge of RXCLK. The
ASYNCH/SYNCH converter is bypassed when
synchronous mode is selected and data is
transmitted out at the same rate as it is input.
DPSK MODULATOR/DEMODULATOR
The 73K212AL modulates a serial bit stream into
dibit pairs that are represented by four possible
phase shifts as prescribed by the Bell 212A
standard. The baseband signal is then filtered to
reduce intersymbol interference on the bandlimited
2-wire telephone line. Transmission occurs using
either a 1200 Hz (originate mode) or 2400 Hz carrier
(answer mode). Demodulation is the reverse of the
modulation process, with the incoming analog signal
eventually decoded into di-bits and converted back
to a serial bit stream. The demodulator also recovers
the clock which was encoded into the analog signal
during modulation. Demodulation occurs using either
a 1200 Hz carrier (answer mode or ALB originate
mode) or a 2400 Hz carrier (originate mode or ALB
answer mode). The 73K212AL uses a phase locked
loop coherent demodulation technique for optimum
receiver performance.
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