19-1941; Rev 0; 4/01
±±15k EꢀDꢁ-rotected, Isolated, 3.3k
Rꢀꢁ481/Rꢀꢁ422 Data Interfaces
General Description
____________________________Features
The MAX3480EA/MAX3480EB are electrically isolated
RS-485/RS-422 data-communications interfaces. The
RS-485/RS-422 I/O pins are protected against ±±5ꢀk
electrostatic discharge (ESD) shocꢀs, without latchup.
Transceivers, optocouplers, and a transformer are all
included in one low-cost, 28-pin DIP pacꢀage. A single
+3.3k supply on the logic side powers both sides of the
interface.
ꢀ Isolated Data Interface Guaranteed to 1260V
RMS
(1min)
ꢀ
15kV ESD Protection for I/O Pins
ꢀ Slew-Rate-Limited Data Transmission (160kbps for
MAX3480EB)
ꢀ High-Speed, Isolated, 2.5Mbps RS-485 Interface
(MAX3480EA)
The MAX3480EB features reduced-slew-rate drivers
that minimize EMI and reduce reflections caused by
improperly terminated cables, allowing error-free data
transmission at data rates up to ±60ꢀbps. The
MAX3480EA’s driver slew rate is not limited, allowing
transmission rates up to 2.5Mbps.
ꢀ Single +3.3V Supply
ꢀ Current Limiting and Thermal Shutdown for
Driver Overload Protection
ꢀ Standard 28-Pin DIP Package
Drivers are short-circuit current limited and are protect-
ed against excessive power dissipation by thermal
shutdown circuitry that places the driver outputs into a
high-impedance state. The receiver input has a fail-safe
feature that guarantees a logic-high output if the input
is open circuit.
ꢀ Allows Up to 128 Transceivers on the Bus
The MAX3480EA/MAX3480EB are guaranteed to with-
stand ±260k
(±min) or ±520k
(±s). Their isolated
RMS
RMS
-in Configuration
inputs and outputs meet RS-485/RS-422 specifications.
TOP VIEW
________________________Applications
Isolated RS-485/RS-422 Data Interface
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networꢀs
Automatic Test Equipment
MAX3480EA
MAX3480EB
V
V
AC1
AC2
ISO V
B
CC1
1
2
28
27
26
25
24
23
22
21
CC2
D1
3
CC1
HkAC/Building Control Networꢀs
Telecom
D2
4
ISO RO DRV
GND1
5
MAX845
MAX485E
MAX487E
6
FS
A
Ordering Information
SD
ISO DI IN
7
DATA
RATE
(kbps)
V
V
8
ISO DE IN
ISO COM1
CC3
DI
PIN-
PACKAGE*
TEMP.
RANGE
PART
9
20
19
18
17
10
ISO DI DRV
CC4
MAX3480EACPI
0°C to +70°C 28 Plastic DIP
2500
2500
250
ISO V
CC2
DE 11
MAX3480EAEPI -40°C to +85°C 28 Plastic DIP
MAX3480EBCPI 0°C to +70°C 28 Plastic DIP
ISO DE DRV
GND2
RO
12
13
14
MAX3480EBEPI -40°C to +85°C 28 Plastic DIP
250
16 ISO COM2
ISO RO LED
V
CC5
15
*See Reliability section at end of data sheet.
ISOLATION BARRIER
DIP
________________________________________________________________ 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.