19-1940; Rev 0; 4/01
±15kV ESD-Protected, Isolated RS-485/RS-422
Data Interfaces
_________________General Description
The MAX1480EA/MAX1480EC/MAX1490EA/MAX1490EB
are complete, electrically isolated, RS-485/RS-422 data
communications interface solutions in a hybrid microcir-
cuit. The RS-485/RS-422 I/O pins are protected against
±15kV electrostatic discharge (ESD) shocks, without
latchup. 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.
The MAX1480EC/MAX1490EB feature 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 160kbps. The
MAX1480EA/MAX1490EA driver slew rate is not limited,
allowing transmission rates up to 2.5Mbps. The
MAX1480EA/MAX1480EC are designed for half-duplex
communication, while the MAX1490EA/MAX1490EB fea-
ture full-duplex communication.
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
MAX1480EA/MAX1480EC, RO high for the MAX1490EA/
MAX1490EB) if the input is open circuit.
The MAX1480EA/MAX1480EC/MAX1490EA/MAX1490EB
withstand 1260V
RMS
(1min) or 1520V
RMS
(1s). Their iso-
lated outputs meet all RS-485/RS-422 specifications. The
MAX1480EA/MAX1480EC are available in a 28-pin DIP
package, and the MAX1490EA/MAX1490EB are available
in a 24-pin DIP package.
.
____________________________Features
o
Isolated Data Interface, Guaranteed to 1260V
RMS
(1min)
o
±15kV ESD Protection on I/O Pins
o
Slew-Rate Limited for Errorless Data
Transmission (MAX1480EC/MAX1490EB)
o
High-Speed, Isolated, 2.5Mbps RS-485/RS-422
Interface (MAX1480EA/MAX1490EA)
o
Full-Duplex Data Communication
(MAX1490EA/MAX1490EB)
o
Single +5V Supply
o
Current Limiting and Thermal Shutdown for
Driver Overload Protection
o
Standard 0.6in DIP Packages
28-Pin DIP (MAX1480EA/MAX1480EC)
24-Pin DIP (MAX1490EA/MAX1490EB)
MAX1480E/MAX1490E
_______________Ordering Information
PART
†
MAX1480EACPI
MAX1480EAEPI
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 C parts is
up to 250kbps.
*See Reliability section at end of data sheet.
Pin Configurations
TOP VIEW
V
CC1
V
CC2
D1
D2
GND1
1
2
3
4
5
MAX845E
MAX488E
MAX490E
24 AC1
23 AC2
________________________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
Telecom
MAX1490EA/
MAX1490EB
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
Selector Guide appears at end of data sheet.
Pin Configurations continued at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
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.
±15kV ESD-Protected, Isolated RS-485/RS-422
Data Interfaces
MAX1480E/MAX1490E
ABSOLUTE MAXIMUM RATINGS
With Respect to GND_
Supply Voltage (V
CC_
)..........................................-0.3V to +6V
Control Input Voltage (SD, FS)..............-0.3V to (V
CC_
+ 0.3V)
Receiver Output Voltage (RO, RO).......-0.3V to (V
CC_
+ 0.3V)
Output Switch Voltage (D1, D2).......................................+12V
With Respect to ISO COM_
Control Input Voltage (ISO DE_) ....-0.3V to (ISO V
CC_
+ 0.3V)
Driver Input Voltage (ISO DI_) .......-0.3V to (ISO V
CC_
+ 0.3V)
Receiver Output Voltage (ISO RO_) ..-0.3V to (ISO V
CC_
+ 0.3V)
Driver Output Voltage (A, B, Y, Z) ......................-8V to +12.5V
Receiver Input Voltage (A, B).............................-8V to +12.5V
LED Forward Current (DI, DE, ISO RO LED) ......................50mA
Continuous Power Dissipation (T
A
= +70°C)
24-Pin Plastic DIP (derate 8.7mW°C above +70°C) ....696mW
28-Pin Plastic DIP (derate 9.09mW/°C above +70°C) .727mW
Operating Temperature Ranges
MAX1480E_CPI/MAX1490E_CPI ........................0°C to +70°C
MAX1480E_EPI/MAX1490E_EPI ......................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
CC_
= +5V ±10%, V
FS
= V
CC_
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= +5V and T
A
= +25°C.)
(Notes 1, 2)
PARAMETER
Switch Frequency
SYMBOL
f
SWL
f
SWH
V
FS
= 0
FS = V
CC_
or open
MAX1480EA,
DE
´
= V
CC_
or open
MAX1480EC,
DE
´
= V
CC_
or open
MAX1490EA
MAX1490EB
Shutdown Supply Current
(Note 3)
Shutdown Input Threshold
Shutdown Input Leakage
Current
FS Input Threshold
FS Input Pullup Current
FS Input Leakage Current
Input High Voltage
Input Low Voltage
Isolation Voltage
Isolation Resistance
Isolation Capacitance
Differential Driver Output
(No Load)
Differential Driver Output
(with Load)
V
IH
V
IL
V
ISO
R
ISO
C
ISO
V
OD1
V
OD2
R = 50Ω (RS-422)
R = 27Ω (RS-485), Figure 4
2
1.5
V
FSH
V
FSL
High
Low
FS low
FS high
DE
´
, DI
´
, Figures 1 and 2
DE
´
, DI
´
, Figures 1 and 2
T
A
= +25°C, 1min (Note 4)
T
A
= +25°C, V
ISO
= 50VDC
T
A
= +25°C, f = 1MHz
1260
100
10,000
10
8
V
CC
- 0.4
0.4
2.4
0.8
50
10
I
SHDN
V
SDH
V
SDL
SD = V
CC_
High
Low
2.4
0.8
10
R
L
=
∞
R
L
= 54Ω
R
L
=
∞
R
L
= 54Ω
R
L
=
∞
R
L
= 54Ω
R
L
=
∞
R
L
= 54Ω
CONDITIONS
MIN
TYP
535
725
85
145
55
120
130
180
65
130
0.2
120
120
180
125
mA
MAX
UNITS
kHz
mA
Operating Supply Current
I
CC
µA
V
pA
V
µA
pA
V
V
V
RMS
MΩ
pF
V
V
5
2
_______________________________________________________________________________________
±15kV ESD-Protected, Isolated RS-485/RS-422
Data Interfaces
MAX1480E/MAX1490E
ELECTRICAL CHARACTERISTICS (continued)
(V
CC_
= +5V ±10%, V
FS
= V
CC_
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= +5V and T
A
= +25°C.)
(Notes 1, 2)
PARAMETER
Change in Magnitude of
Driver Output Voltage for
Complementary Output States
Driver Common-Mode Output
SYMBOL
∆V
OD
V
OC
CONDITIONS
Differential
R = 27Ω or 50Ω, Figure 4
Common mode
R = 27Ω or 50Ω, Figure 4
MAX1490EA/
MAX1490EB
MAX1480EA/
MAX1480EC
MAX1490EA/
MAX1490EB
MAX1480EA/
MAX1480EC
(MAX1480E_)
(MAX1490E_)
48
12
-0.2
70
0.4
250
100
±15
0.2
0.3
4
1.0
0.25
mA
0.8
0.2
kΩ
V
mV
V
µA
mA
kV
V
MIN
TYP
MAX
0.3
V
UNITS
V
IN
= +12V
Input Current (A, B)
ISO I
IN
DE
´
= 0,
V
CC_
= 0 or +5.5V
V
IN
= -7V
Receiver Input Resistance
Receiver Differential Threshold
Receiver Input Hysteresis
Receiver Output Low Voltage
Receiver Output High Current
Driver Short-Circuit Current
ESD Protection
R
IN
V
TH
∆V
TH
V
OL
I
OH
ISO I
OSD
ISO I
OSD
-7V
≤
V
CM
≤
+12V
-7V
≤
V
CM
≤
+12V
V
CM
= 0
Using resistor values listed in Tables 1 and 2
V
OUT
= 5.5V
-7V
≤
V
O
≤
12V (Note 5)
A, B, Y, and Z pins, tested using Human Body
Model, Figures 1 and 2
SWITCHING CHARACTERISTICS—MAX1480EA/MAX1490EA
(V
CC_
= +5V ±10%, V
FS
= V
CC_
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= +5V and T
A
= +25°C.)
PARAMETER
Driver Input to Output
Propagation Delay
Driver Output Skew
Driver Rise or Fall Time
Driver Enable to Output High
(MAX1480EA Only)
Driver Enable to Output Low
(MAX1480EA Only)
Driver Disable Time from Low
(MAX1480EA Only)
Driver Disable Time from High
(MAX1480EA Only)
Receiver Input to Output
Propagation Delay
SYMBOL
t
PLH
t
PHL
t
SKEW
t
R,
t
F
t
ZH
t
ZL
t
LZ
t
HZ
t
PLH
t
PHL
CONDITIONS
Figures 5 and 7, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 5 and 7, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
Figures 5 and 7, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
Figures 6 and 8, C
L
= 100pF, S2 closed
Figures 6 and 8, C
L
= 100pF, S1 closed
Figures 6 and 8, C
L
= 15pF, S1 closed
Figures 6 and 8, C
L
= 15pF, S2 closed
Figures 5 and 10, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
MIN
TYP
90
60
30
15
1.0
1.0
0.5
0.5
120
90
MAX
275
275
100
50
1.8
1.8
1.8
1.8
225
225
UNITS
ns
ns
ns
µs
µs
µs
µs
ns
_______________________________________________________________________________________
3
±15kV ESD-Protected, Isolated RS-485/RS-422
Data Interfaces
MAX1480E/MAX1490E
SWITCHING CHARACTERISTICS—MAX1480EA/MAX1490EA (continued)
(V
CC_
= +5V ±10%, V
FS
= V
CC_
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= +5V and T
A
= +25°C.)
PARAMETER
|t
PLH
- t
PHL
| Differential
Receiver Skew
Maximum Data Rate
Time to Shutdown
Shutdown to Driver Output High
Shutdown to Driver Output Low
SYMBOL
t
SKD
f
MAX
t
SHDN
t
ZH(SHDN)
t
ZH(SHDN)
Figures 6 and 9, C
L
= 100pF, S2 closed
Figures 6 and 9, C
L
= 100pF, S1 closed
CONDITIONS
Figures 5 and 10, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
t
SKEW
, t
SKD
, t
PHL
≤
25% of data period
2.5
100
3
3
15
15
MIN
TYP
30
MAX
150
UNITS
ns
Mbps
µs
µs
µs
SWITCHING CHARACTERISTICS—MAX1480EC/MAX1490EB
(V
CC_
= +5V ±10%, V
FS
= V
CC_
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= +5V and T
A
= +25°C.)
PARAMETER
Driver Input to Output
Propagation Delay
Driver Output Skew
Driver Rise or Fall Time
Driver Enable to Output High
(MAX1480EC Only)
Driver Enable to Output Low
(MAX1480EC Only)
Driver Disable Time from Low
(MAX1480EC Only)
Driver Disable Time from High
(MAX1480EC Only)
Receiver Input to Output
Propagation Delay
|t
PLH
- t
PHL
| Differential
Receiver Skew
Maximum Data Rate
Time to Shutdown
Shutdown to Driver Output High
Shutdown to Driver Output Low
SYMBOL
t
PLH
t
PHL
t
SKEW
t
R,
t
F
t
ZH
t
ZL
t
LZ
t
HZ
t
PLH
t
PHL
t
SKD
f
MAX
t
SHDN
t
ZH(SHDN)
t
ZL(SHDN)
Figures 6 and 9, C
L
= 100pF, S2 closed
Figures 6 and 9, C
L
= 100pF, S1 closed
CONDITIONS
Figures 5 and 7, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
Figures 5 and 7, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
Figures 5 and 7, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
Figures 5 and 7, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
Figures 6 and 8, C
L
= 100pF, S2 closed
Figures 6 and 8, C
L
= 100pF, S1 closed
Figures 6 and 8, C
L
= 15pF, S1 closed
Figures 6 and 8, C
L
= 15pF, S2 closed
Figures 5 and 10, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
Figures 5 and 10, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
t
SKEW
, t
SKD
≤
25% of data period
160
100
3
3
15
15
MIN
TYP
1.4
1.1
300
1.0
1.4
1.4
2.0
1.7
0.9
1.1
200
MAX
3.0
3.0
1200
2.0
4.5
4.5
4.5
4.5
3.0
3.0
UNITS
µs
ns
µs
µs
µs
µs
µs
µs
ns
kbps
µs
µs
µs
Note 1:
All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to logic-
side ground (GND_), unless otherwise specified.
Note 2:
For DE
´
and DI
´
pin descriptions, see
Detailed Block Diagram and Typical Application Circuit
(Figure 1 for MAX1480EA/
MAX1480EC, Figure 2 for MAX1490EA/MAX1490EB).
Note 3:
Shutdown supply current is the current at V
CC1
and V
CC2
when shutdown is enabled.
Note 4:
Limit guaranteed by applying 1520V
RMS
for 1s. Test voltage is applied between all pins on one side of the package to all
pins on the other side of the package, e.g., between pins 1–14 and pins 15–28 on the 28-pin package.
Note 5:
Applies to peak current (see
Typical Operating Characteristics).
Although the MAX1480EA/MAX1480EC and
MAX1490EA/MAX1490EB provide electrical isolation between logic ground and signal paths, they do not provide isolation
between external shields and the signal paths (see
Isolated Common Connection
section).
4
_______________________________________________________________________________________
±15kV ESD-Protected, Isolated RS-485/RS-422
Data Interfaces
__________________________________________Typical Operating Characteristics
(V
CC_
= +5V, V
FS
= V
CC_
, Figures 1 and 2, T
A
= +25°C, unless otherwise noted.)
MAX1480E/MAX1490E
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
MAX1480E/90E TOC01
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
MAX1480E/90E TOC02
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
4.75
OUTPUT HIGH VOLTAGE (V)
4.50
4.25
4.00
3.75
3.50
3.25
3.00
MEASURED AT ISO RO DRV
I
RO
= 8mA
MAX1480E/90E TOC03
80
70
OUTPUT CURRENT (mA)
60
50
40
30
20
10
0
0
MEASURED AT ISO RO DRV
-30
-25
OUTPUT CURRENT (mA)
-20
-15
-10
-5
0
MEASURED AT ISO RO DRV
5.00
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT LOW VOLTAGE (V)
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT HIGH VOLTAGE (V)
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
MAX1480E/90E TOC04
OUTPUT CURRENT vs.
DRIVER OUTPUT LOW VOLTAGE
MAX1480E/90E TOC05
OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
-90
-80
OUTPUT CURRENT (mA)
-70
-60
-50
-40
-30
-20
-10
0
MAX1480E/90E TOC06
0.8
0.7
OUTPUT LOW VOLTAGE (V)
0.6
0.5
0.4
0.3
0.2
0.1
0
-40
MEASURED AT ISO RO DRV
I
RO
= 8mA
180
160
OUTPUT CURRENT (mA)
140
120
100
80
60
40
20
0
-100
-20
0
20
40
60
80
0
1
2
3 4
5
6
7 8
9 10 11 12
-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6
OUTPUT HIGH VOLTAGE (V)
TEMPERATURE (°C)
OUTPUT LOW VOLTAGE (V)
DRIVER OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX1480E/90E TOC07
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
MAX1480E/90E TOC08
SHUTDOWN CURRENT
vs. TEMPERATURE
0.35
SHUTDOWN CURRENT (µA)
0.30
0.25
0.20
0.15
0.10
0.05
0
SD = V
CC_
, DI
´
= V
CC_
DE
´
= V
CC_
(MAX1480EC ONLY)
MEASURED AT V
CC1
AND V
CC2
MAX1480E/90E TOC09
80
DI
´
= HIGH OR OPEN
70
OUTPUT CURRENT (mA)
60
50
40
30
20
10
0
0
3.0
DIFFERENTIAL OUTPUT VOLTAGE (V)
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2.0
DI
´
= HIGH OR OPEN
R
L
= 54Ω
0.40
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
DIFFERENTIAL OUTPUT VOLTAGE (V)
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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