MAXIM MAX1480A, MAX1480B, MAX1480C, MAX1490A, MAX1490B User Manual
_________________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 powers both sides of the interface.
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/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.
________________________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
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
Complete, Isolated RS-485/RS-422
Data Interface
________________________________________________________________ Maxim Integrated Products 1
1
24
23
22
21
20
19
18
17
2
3
4
5
6
7
8
AC1
AC2
ISO V
CC1
ISO RO DRVD2
D1
A
B
Z
Y
SD
FS
GND1
16
15
14
13
9
10
11
12
ISO COM1
ISO DI DRV
ISO V
CC2
ISO RO LED
GND2
RO
DI
DIP
V
CC2
V
CC3
V
CC4
V
CC1
MAX1490A/B
MAX845
MAX488
MAX490
TOP VIEW
ISOLATION BARRIER
Pin Configurations
19-0259; Rev 5; 5/05
_______________Ordering Information
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.
Pin Configurations continued at end of data sheet.
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.
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
_____________________Selection Table
PART
HALF/
FULL
DATA
SLEW-
RATE
DRIVER
ENABLE
TIME
(µS)
MAX1480A Half 2.5 No 0.2
MAX1480B Half 0.25 Yes 35
MAX1480C Half 0.25 Yes 0.5
MAX1490A Full 2.5 No —
MAX1490B Full 0.25 Yes —
RATE
DUPLEX
(MBPS)
LIMITED
Complete, Isolated RS-485/RS-422
Data Interface
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC_
= 5V ±10%, VFS= V
CC_
, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= 5V and TA= +25°C.) (Notes 1, 2)
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.
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
MAX1480_CPI/MAX1490_CPG............................0°C to +70°C
MAX1480_EPI/MAX1490_EPG .........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
MAX1480A/B/C/MAX1490A/B
PARAMETER
CONDITIONS MIN
UNITS
f
SWL
VFS = 0V
Switch Frequency
f
SWH
FS = V
CC_
or open
kHz
60 90
MAX1480A,
DE´ = V
CC_
or open
R
L
= 54Ω
35 45
MAX1480B,
DE´ = V
CC_
or open
R
L
= 54Ω 95
35 75
MAX1480C,
DE´ = V
CC_
or open
R
L
= 54Ω 95
150
MAX1490A
R
L
= 54Ω
65 125
Operating Supply Current I
CC
MAX1490B
R
L
= 54Ω
mA
Shutdown Supply Current
(Note 3)
I
SHDN
SD = V
CC_
µA
V
SDH
High 2.4
Shutdown Input Threshold
V
SDL
Low 0.8
V
Shutdown Input Leakage Current
10 pA
V
FSH
High 2.4
FS Input Threshold
V
FSL
Low 0.8
V
FS Input Pullup Current FS low 50 µA
FS Input Leakage Current FS high 10 pA
Input High Voltage V
IH
DE´, DI´
V
Input Low Voltage V
IL
DE´, DI´ 0.4 V
Isolation Resistance R
ISO
TA = +25°C, V
ISO
= 50VDC 100
MΩ
Isolation Capacitance C
ISO
TA = +25°C, V
ISO
= 50VDC 10 pF
Differential Driver Output
(No Load)
V
OD1
8V
SYMBOL
TYP MAX
535
725
RL = ∞, +25°C only
120
RL = ∞, +25°C only
RL = ∞, +25°C only
RL = ∞, +25°C only 100
170
130
RL = ∞, +25°C only
0.2
V
- 0.4
CC_
10,000
MAX1480A/B/C/MAX1490A/B
Complete, Isolated RS-485/RS-422
Data Interface
_______________________________________________________________________________________ 3
PARAMETER
SYMBOL
CONDITIONS MIN
TYP
MAX
UNITS
R = 50Ω (RS-422) 2
Differential Driver Output
(With Load)
V
OD2
R = 27Ω (RS-485), Figure 4 1.5 5.0
V
Differential 0.3
Change in Magnitude of
Differential Output Voltage for
Complementary Output States
∆V
OD
R = 27Ω or 50Ω,
Figure 4
Common mode 0.3
V
Driver Common-Mode Output
Voltage
V
OC
R = 27Ω or 50Ω, Figure 4 4 V
1
MAX1490A/B
0.8
Input Current (A, B) ISO I
IN
DE´ = 0V,
V
CC_
= 0V
or 5.5V
MAX1490A/B 0.2
mA
48
Receiver Input Resistance R
IN
-7V ≤ VCM ≤ 12V
MAX1490A/B 12
kΩ
Receiver Differential Threshold
Voltage
V
TH
-7V ≤ VCM ≤ 12V -0.2
V
Receiver Input Hysteresis ∆V
TH
VCM = 0V 70 mV
Receiver Output/Receiver Output
Low Voltage
V
OL
Using resistor values listed in
Tables 1 and 2
0.4 V
Receiver Output/Receiver Output
High Current
I
OH
V
OUT
= 5.5V 250 µA
Driver Short-Circuit Current
-7V ≤ VO ≤ 12V (Note 4)
mA
ELECTRICAL CHARACTERISTICS (continued)
(V
CC_
= 5V ±10%, VFS= V
CC_
, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= 5V and TA= +25°C.) (Notes 1, 2)
SWITCHING CHARACTERISTICS—MAX1480A/MAX1490A
(V
CC_
= 5V ±10%, FS = V
CC_
, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= 5V and TA = +25°C.)
PARAMETER
CONDITIONS MIN
UNITS
t
PLH
275
Driver Input to Output
Propagation Delay
t
PHL
Figures 5 and 7, R
DIFF
= 54Ω, CL1 = C
L2
= 100pF
275
ns
Driver Output Skew t
SKEW
Figures 5 and 7, R
DIFF
= 54Ω, CL1 = C
L2
= 100pF
25 90 ns
Driver Rise or Fall Time t
R, tF
Figures 5 and 7, R
DIFF
= 54Ω, CL1 = C
L2
= 100pF
15 40 ns
Driver Enable to Output High
(MAX1480A Only)
t
ZH
Figures 6 and 8, CL = 100pF, S2 closed
1.5 µs
Driver Enable to Output Low
(MAX1480A Only)
t
ZL
Figures 6 and 8, CL = 100pF, S1 closed
1.5 µs
Driver Disable Time from Low
(MAX1480A Only)
t
LZ
Figures 6 and 8, CL = 15pF, S1 closed
1.5 µs
Driver Disable Time from High
(MAX1480A Only)
t
HZ
Figures 6 and 8, CL = 15pF, S2 closed
1.5 µs
t
PLH
225
Receiver Input to Output
Propagation Delay
t
PHL
Figures 5 and 10, R
DIFF
= 54Ω, CL1 = C
L2
= 100pF
225
ns
VIN = 12V
V
IN
= -7V
MAX1480A/B/C
MAX1480A/B/C
MAX1480A/B/C
0.25
+0.2
ISO I
OSD
SYMBOL
100
TYP MAX
100
100
0.2
0.2
0.2
0.2
100
100
MAX1480A/B/C/MAX1490A/B
Complete, Isolated RS-485/RS-422
Data Interface
4 _______________________________________________________________________________________
SWITCHING CHARACTERISTICS—MAX1480A/MAX1490A (continued)
(V
CC_
= 5V ±10%, FS = V
CC_
, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= 5V and TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS MIN
TYP
MAX
UNITS
|t
PLH
- t
PHL
| Differential Receiver
Skew
t
SKD
Figures 5 and 10, R
DIFF
= 54Ω, CL1 = C
L2
= 100pF
20 ns
Maximum Data Rate f
MAX
t
PLH
, t
PHL
< 50% of data period 2.5
Mbps
Time to Shutdown t
SHDN
µs
Shutdown to Driver Output High
)
Figures 6 and 9, CL = 100pF, S2 closed 3 10 µs
Shutdown to Driver Output Low
)
Figures 6 and 9, CL = 100pF, S1 closed 3 10 µs
SWITCHING CHARACTERISTICS—MAX1480B/MAX1480C/MAX1490B
(V
CC_
= 5V ±10%, FS = V
CC_
, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= 5V and TA = +25°C.)
PARAMETER
CONDITIONS MIN
UNITS
t
PLH
2 3.0
Driver Input to Output
Propagation Delay
t
PHL
Figures 5 and 7, R
DIFF
= 54Ω,
C
L1
= CL2 = 100pF
2 3.0
µs
Driver Output Skew t
SKEW
Figures 5 and 7, R
DIFF
= 54Ω,
C
L1
= CL2 = 100pF
ns
Driver Rise or Fall Time t
R, tF
Figures 5 and 7, R
DIFF
= 54Ω,
C
L1
= CL2 = 100pF
2.0 µs
Driver Enable to Output High
(MAX1480B Only)
t
ZH
Figures 6 and 8, CL = 100pF, S2 closed 35 100 µs
Driver Enable to Output Low
(MAX1480B Only)
t
ZL
Figures 6 and 8, CL = 100pF, S1 closed 35 100 µs
Driver Disable Time from Low
(MAX1480B Only)
t
LZ
Figures 6 and 8, CL = 15pF, S1 closed 13 50 µs
Driver Disable Time from High
(MAX1480B Only)
t
HZ
Figures 6 and 8, CL = 15pF, S2 closed 13 50 µs
Driver Enable to Output High
(MAX1480C Only)
t
ZH
Figures 6 and 8, CL = 100pF, S2 closed
4.5 µs
Driver Enable to Output Low
(MAX1480C Only)
t
ZL
Figures 6 and 8, CL = 100pF, S1 closed
4.5 µs
t
ZH(SHDN
t
ZL(SHDN
SYMBOL
100
TYP MAX
900 1600
1.0
0.5
0.5
MAX1480A/B/C, MAX1490A/B
Complete, Isolated RS-485/RS-422
Data Interface
_______________________________________________________________________________________ 5
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 MAX1480A/
MAX1480B/MAX1480C, Figure 2 for MAX1490A/MAX1490B).
Note 3: Shutdown supply current is the current at V
CC1
and V
CC2
when shutdown is enabled.
Note 4: Applies to peak current (see Typical Operating Characteristics). Although the MAX1480A/B/C and MAX1490A/B 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).
SWITCHING CHARACTERISTICS—MAX1480B/MAX1480C/MAX1490B (continued)
(V
CC_
= 5V ±10%, FS = V
CC_
, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC_
= 5V and TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS MIN
TYP
MAX
UNITS
Driver Disable Time from Low
(MAX1480C Only)
t
LZ
Figures 6 and 8, CL = 15pF, S1 closed
4.5 µs
Driver Disable Time from High
(MAX1480C Only)
t
HZ
Figures 6 and 8, CL = 15pF, S2 closed
4.5 µs
t
PLH
2 3.0
Receiver Input to Output
Propagation Delay
t
PHL
Figures 5 and 10, R
DIFF
= 54Ω,
C
L1
= CL2 = 100pF
2 3.0
µs
|t
PLH
- t
PHL
| Differential Receiver
Skew
t
SKD
Figures 5 and 10, R
DIFF
= 54Ω,
C
L1
= CL2 = 100pF
ns
Maximum Data Rate f
MAX
t
PLH
, t
PHL
< 50% of data period 0.25
Mbps
Time to Shutdown t
SHDN
µs
Shutdown to Driver Output High
)
Figures 6 and 9, CL = 100pF, S2 closed 35 100 µs
Shutdown to Driver Output Low
)
Figures 6 and 9, CL = 100pF, S1 closed 35 100 µs
t
ZH(SHDN
t
ZL(SHDN
2.0
2.0
1200
100
MAX1480A/B/C, MAX1490A/B
Complete, Isolated RS-485/RS-422
Data Interface
6 _______________________________________________________________________________________
__________________________________________Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
0
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
MAX1480/90A/B-01
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
1.5
10
20
30
40
50
60
70
80
MEASURED AT ISO RO DRV
1.00.503.53.02.52.0 5.04.54.0
0
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
MAX1480/90A/B-02
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
1.5
-5
MEASURED AT ISO RO DRV
1.00.503.53.02.52.0 5.04.54.0
-10
-15
-20
-25
-30
3.00
-40 20
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
MAX1480/90A/B-03
TEMPERATURE (°C)
OUTPUT HIGH VOLTAGE (V)
0-20 6040 80
3.25
3.50
3.75
4.00
4.25
4.50
4.75
5.00
MEASURED AT ISO RO DRV
I
RO
= 8mA
0
-40 20
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
MAX1480/90A/B-04
TEMPERATURE (°C)
OUTPUT LOW VOLTAGE (V)
0-20 6040 80
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
MEASURED AT ISO RO DRV
I
RO
= 8mA
0
DRIVER OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX1480/90A/B-07
DIFFERENTIAL OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
1.5
10
20
30
40
50
60
70
80
DI´ = HIGH OR OPEN
1.00.503.53.02.52.0 5.04.54.0
OUTPUT CURRENT vs.
DRIVER OUTPUT LOW VOLTAGE
MAX1480/90A/B-05
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
0
160
180
140
100
120
80
40
60
0
20
123456789101112
0
-7
OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
MAX1480/90A/B-06
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-6 -5 -4 -3 -2 -1 1 2 3 4 5 6
2.0
-40 20
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
MAX1480/90A/B-08
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
0-20 6040 80
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
DI´ = HIGH OR OPEN
R
L
= 54Ω
0
-40 20
MAX1480B/MAX1480C/MAX1490B
SHUTDOWN CURRENT vs. TEMPERATURE
MAX1480/90A/B-09
TEMPERATURE (°C)
SHUTDOWN CURRENT (µA)
0-20 6040 80
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
SD = V
CC_
, DI´ = V
CC_
DE
´ (MAX1480B/C ONLY) = V
CC_
MEASURED AT V
CC1
AND V
CC2
__________________________________________Typical Operating Characteristics
(V
CC_
= 5V, FS = V
CC_
, TA = +25°C, unless otherwise noted.)
MAX1480A/B/C, MAX1490A/B
Complete, Isolated RS-485/RS-422
Data Interface
_______________________________________________________________________________________ 7
_____________________________Typical Operating Characteristics (continued)
(V
CC_
= 5V, FS = V
CC_
, TA = +25°C, unless otherwise noted.)
0
60
40
20
80
100
120
140
160
MAX1480A
SUPPLY CURRENT vs. TEMPERATURE
MAX1480/90A/B-10
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
-40 -20 0 20 40 60 80
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 4.5V
R
L
= 54Ω
R
L
= ∞
V
CC
= 4.5V
DE´ = V
CC
20
60
40
80
100
120
140
MAX1480B
SUPPLY CURRENT vs. TEMPERATURE
MAX1480/90A/B-11
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
-40 -20 0 20 40 60 80
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 5.5V
V
CC
= 5.0V
R
L
= 54Ω
R
L
= ∞
DE´ = V
CC
V
CC
= 4.5V
V
CC
= 4.5V
20
70
60
50
30
40
80
90
100
110
120
MAX1480C
SUPPLY CURRENT vs. TEMPERATURE
MAX1480/90A/B-12
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
-40 -20 0 20 40 60 80
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 4.5V
R
L
= 54Ω
R
L
= ∞
V
CC
= 4.5V
DE´ = V
CC
80
120
100
140
160
180
200
MAX1490A
SUPPLY CURRENT vs. TEMPERATURE
MAX1480/90A/B-13
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
-40 -20 0 20 40 60 80
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 4.5V
R
L
= 54Ω
R
L
= ∞
V
CC
= 4.5V
50
100
90
80
60
70
110
120
130
140
150
MAX1490B
SUPPLY CURRENT vs. TEMPERATURE
MAX1480/90A/B-14
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
-40 -20 0 20 40 60 80
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 5.5V
V
CC
= 5.0V
V
CC
= 4.5V
R
L
= 54Ω
R
L
= ∞
V
CC
= 4.5V
0.1
10
1
100
DRIVER DISABLE TIME
vs. TEMPERATURE
MAX1480/90A/B-15a
TEMPERATURE (°C)
DRIVER DISABLE TIME (µs)
-40 -20 0 20 40 60 80
MAX1480A
MAX1480B
MAX1480C
RL = 54Ω
V
DI´
= 0V MEASURED FROM
DE´ TO VALID OUTPUT
0.1
10
1
100
DRIVER ENABLE TIME
vs. TEMPERATURE
MAX1480/90A/B-15b
TEMPERATURE (°C)
DRIVER ENABLE TIME (µs)
-40 -20 0 20 40 60 80
MAX1480A
MAX1480C
MAX1480B
RL = 54Ω
V
DI´
= 0V MEASURED FROM
DE´ TO VALID OUTPUT
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