73K302L TDK [TDK Electronics], 73K302L Datasheet - Page 23

• Manufacturer Part Number: 73K302L
• Description: Single-Chip Modem
• Manufacturer: TDK [TDK Electronics]

APPLICATIONS INFORMATION
GENERAL CONSIDERATIONS
Figures 1 and 2 show basic circuit diagrams for
K-Series
products are designed to be used in conjunction with
a control processor, a UART or RS-232 serial data
interface, and a DAA phone line interface to function
as a typical intelligent modem. The K-Series ICs
interface directly with Intel 8048 and 80C51
microprocessors for control and status monitoring
purposes. Two typical DAA arrangements are
shown: one for a split ±5 or ±12 volt design and one
for a single 5V design. These diagrams are for
reference only and do not represent production-
ready modem designs.
K-Series devices are available with two control
interface versions: one for a parallel multiplexed
address/data interface, and one for a serial
CB
CC
CD
DD
DB
CA
CF
BA
BB
DA
CONVERTERS
MC145406
LEVEL
U5, U6
RS232
RTS
CTS
DSR
DTR
DCD
TXD
RXD
EXCLK
RXCLK
TXCLK
modem
P1.0
P1.1
P1.2
P1.3
P1.5
P1.6
P3.0
XTL2
N/C
80C51
P1.7
P0.0-7
RESET
XTL1
integrated
P3.1
P3.2
ALE
WR
INT
RD
FIGURE 1: Basic Box Modem with Dual-Supply Hybrid
CLK
INT
RD
WR
ALE
CS
39 pF
C14
RESET
XTL1
circuits.
K-SERIES
11.0592
POWER
FAMILY
MHZ
LOW
Y1
XTL2
18 pF
+5V
C13
VREF
GND
ISET
RXA
1 µF
VDD
C12
TXA
+5V
K-Series
0.1 µF
2.2M
0.1 µF
R10
C11
C10
0.1 µF
0.1 µF
RXA
TXA
C7
C6
0.1 µF
C9
20K
R6
23
LM 1458
+
-
300 pF
43.2K
+
C2
R7
interface. The parallel version is intended for use
with 8039/48 or 8031/51 microcontrollers from Intel
or many other manufacturers. The serial interface
can be used with other microcontrollers or in
applications where only a limited number of port
lines are available or the application does not lend
itself to a multiplexed address/data interface. The
parallel versions may also be used in the serial
mode, as explained in the data sheet pin description.
In most applications the controller will monitor the
serial data for commands from the DTE and the
received data for break signals from the far end
modem. In this way, commands to the modem are
sent over the same line as the transmitted data. In
other applications the RS-232 interface handshake
lines are used for modem control.
22 µF
V+
V–
C8
U1B
1000 pF
C3
U1A
LM 1458
390 pF
37.4K
475 1%
ZENER
D3, D4
R5
4.7V
C1
R1
+
-
10K
R9
0.033 µF
3.6K
R3
C4
IN914
5.1K
R4
D2
20K
R4
+5V
Q1
Single-Chip Modem
2N2222A
Bell 212A, 103, 202
MIDCOM
671-8005
K1
T1
IN4004
D1
+5
22K
22K
0.47 µF
R8
250V
C5
4N35
U2
V250L20
MOV
VR1
T
R