19-0259; Rev 5; 5/05
Complete, Isolated RS-485/RS-422
Data Interface
Next-Generation Device Features
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 powers both sides of the interface.
♦ 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
The MAX1480B/MAX1480C/MAX1490B feature reducedslew-rate drivers that minimize EMI and reduce reflections 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 communication, while the MAX1490A/B feature full-duplex communication.
Drivers are short-circuit current limited and protected
against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a highimpedance 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) if the
input is open circuit.
The MAX1480A/MAX1480B/MAX1480C/MAX1490A/
MAX1490B typically withstand 1600VRMS (1 minute) or
2000VRMS (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.
________________________Applications
_______________Ordering Information
PART†
TEMP RANGE
PIN-PACKAGE
MAX1480ACPI
0°C to +70°C
28 Wide Plastic DIP
MAX1480AEPI
-40°C to +85°C
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
DATA
RATE
(MBPS)
SLEWRATE
LIMITED
DRIVER
ENABLE
TIME
(µs)
0.2
MAX1480A
Half
2.5
No
MAX1480B
Half
0.25
Yes
35
MAX1480C
Half
0.25
Yes
0.5
MAX1490A
Full
2.5
No
—
MAX1490B
Full
0.25
Yes
—
Pin Configurations
TOP VIEW
Isolated RS-485/RS-422 Data Interface
VCC1
1
Transceivers for EMI-Sensitive Applications
VCC2
2
23 AC2
Industrial-Control Local Area Networks
D1
3
22 ISO VCC1
Automatic Test Equipment
D2
4
21 ISO RO DRV
GND1
5
20 A
MAX488
MAX490
FS 6
MAX845
HVAC/Building Control Networks
24 AC1
MAX1490A/B
19 B
SD
7
18 Z
VCC3
8
17 Y
DI
9
16 ISO COM1
VCC4 10
15 ISO DI DRV
14 ISO VCC2
RO 11
13 ISO RO LED
GND2 12
ISOLATION BARRIER
DIP
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX1480A/B/C/MAX1490A/B
_________________General Description
