19-0259; Rev 4; 10/03
Complete, Isolated RS-485/RS-422
Data Interface
_________________General Description
The MAX1480A/MAX1480B/MAX1480C/MAX1490A/
MAX1490B are complete, electrically isolated, RS-485/
RS-422 data-communications interface solutions in a
hybrid microcircuit. Transceivers, optocouplers, and a
transformer provide a complete interface in a standard
DIP package. A single +5V supply on the logic side pow-
ers both sides of the interface.
The MAX1480B/MAX1480C/MAX1490B feature reduced-
slew-rate drivers that minimize EMI and reduce reflec-
tions caused by improperly terminated cables, allowing
error-free data transmission at data rates up to 250kbps.
The MAX1480A/MAX1490A driver slew rate is not limited,
allowing transmission rates up to 2.5Mbps. The
MAX1480A/B/C are designed for half-duplex communi-
cation, while the MAX1490A/B feature full-duplex com-
munication.
Drivers are short-circuit current limited and protected
against excessive power dissipation by thermal shut-
down circuitry that places the driver outputs into a high-
impedance state. The receiver input has a fail-safe
feature that guarantees a known output (RO low for the
MAX1480A/B/C, RO high for the MAX1490A/B/C) if the
input is open circuit.
The MAX1480A/MAX1480B/MAX1480C/MAX1490A/
MAX1490B typically withstand 1600V
RMS
(1 minute) or
2000V
RMS
(1 second). Their isolated outputs meet all
RS-485/RS-422 specifications. The MAX1480A/B/C are
available in a 28-pin DIP package, and the MAX1490A/B
are available in a 24-pin DIP package.
Next-Generation Device Features
♦
For Integrated ESD Protection
MAX1480E/MAX1490E: ±15kV ESD-Protected,
Isolated RS-485/RS-422 Data Interfaces
♦
For Space-Constrained Applications
MAX3157: High CMRR, RS-485 Transceiver with
±50V Isolation
MAX1480A/B/C/MAX1490A/B
_______________Ordering Information
PART
†
MAX1480ACPI
MAX1480AEPI
TEMP RANGE
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
28 Wide Plastic DIP
28 Wide Plastic DIP
Ordering Information continued at end of data sheet.
†
Data rate for “A” parts is up to 2.5Mbps. Data rate for “B” and
“C” parts is up to 250kbps.
_____________________Selection Table
PART
HALF/
FULL
DUPLEX
Half
Half
Half
Full
Full
DATA
RATE
(MBPS)
2.5
0.25
0.25
2.5
0.25
SLEW-
RATE
LIMITED
No
Yes
Yes
No
Yes
DRIVER
ENABLE
TIME
(µS)
0.2
35
0.5
—
—
MAX1480A
MAX1480B
MAX1480C
MAX1490A
MAX1490B
Pin Configurations
TOP VIEW
V
CC1
V
CC2
D1
D2
GND1
1
2
3
4
5
MAX845
MAX488
MAX490
________________________Applications
Isolated RS-485/RS-422 Data Interface
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
Automatic Test Equipment
HVAC/Building Control Networks
24 AC1
23 AC2
MAX1490A/B
22 ISO V
CC1
21 ISO RO DRV
20 A
19 B
18 Z
17 Y
16 ISO COM1
15 ISO DI DRV
14 ISO V
CC2
13 ISO RO LED
ISOLATION BARRIER
FS 6
SD
7
V
CC3
8
DI
9
V
CC4
10
RO 11
GND2 12
DIP
Pin Configurations continued at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
