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104211090 UNPDF
19-0122; Rev 5; 2/96
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
_______________General Description
The MAX481, MAX483, MAX485, MAX487–MAX491, and
MAX1487 are low-power transceivers for RS-485 and RS-
422 communication. Each part contains one driver and one
receiver. The MAX483, MAX487, MAX488, and MAX489
feature reduced slew-rate drivers that minimize EMI and
reduce reflections caused by improperly terminated cables,
thus allowing error-free data transmission up to 250kbps.
The driver slew rates of the MAX481, MAX485, MAX490,
MAX491, and MAX1487 are not limited, allowing them to
transmit up to 2.5Mbps.
These transceivers draw between 120µA and 500µA of
supply current when unloaded or fully loaded with disabled
drivers. Additionally, the MAX481, MAX483, and MAX487
have a low-current shutdown mode in which they consume
only 0.1µA. All parts operate from a single 5V supply.
Drivers are short-circuit current limited and are protected
against excessive power dissipation by thermal shutdown
circuitry that places the driver outputs into a high-imped-
ance state. The receiver input has a fail-safe feature that
guarantees a logic-high output if the input is open circuit.
The MAX487 and MAX1487 feature quarter-unit-load
receiver input impedance, allowing up to 128 MAX487/
MAX1487 transceivers on the bus. Full-duplex communi-
cations are obtained using the MAX488–MAX491, while
the MAX481, MAX483, MAX485, MAX487, and MAX1487
are designed for half-duplex applications.
________________________Applications
Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
____________________________Features
©
In µMAX Package: Smallest 8-Pin SO
©
Slew-Rate Limited for Error-Free Data
Transmission (MAX483/487/488/489)
©
0.1µA Low-Current Shutdown Mode
(MAX481/483/487)
©
Low Quiescent Current:
120µA (MAX483/487/488/489)
230µA (MAX1487)
300µA (MAX481/485/490/491)
©
-7V to +12V Common-Mode Input Voltage Range
©
Three-State Outputs
©
30ns Propagation Delays, 5ns Skew
(MAX481/485/490/491/1487)
©
Full-Duplex and Half-Duplex Versions Available
©
Operate from a Single 5V Supply
©
Allows up to 128 Transceivers on the Bus
(MAX487/MAX1487)
©
Current-Limiting and Thermal Shutdown for
Driver Overload Protection
______________Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX481 CPA
0°C to +70°C
8 Plastic DIP
MAX481CSA
0°C to +70°C
8 SO
MAX481CUA
0°C to +70°C
8 µMAX
MAX481C/D
0°C to +70°C
Dice*
Ordering Information continued at end of data sheet.
* Contact factory for dice specifications.
______________________________________________________________Selection Table
PART
NUMBER
HALF/FULL
DUPLEX
DATA RATE
(Mbps)
SLEW-RATE
LIMITED
LOW-POWER
SHUTDOWN
RECEIVER/
DRIVER
ENABLE
QUIESCENT
CURRENT
(
A)
NUMBER OF
TRANSMITTERS
ON BUS
PIN
COUNT
MAX481
MAX483
MAX485
MAX487
MAX488
MAX489
MAX490
MAX491
MAX1487
Half
Half
Half
Half
Full
Full
Full
Full
Half
2.5
0.25
2.5
0.25
0.25
0.25
2.5
2.5
2.5
No
Yes
No
Yes
Yes
Yes
No
No
No
Yes
Yes
No
Yes
No
No
No
No
No
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
300
120
300
120
120
120
300
300
230
32
32
32
128
32
32
32
32
128
8
8
8
8
8
14
8
14
8
________________________________________________________________ Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
m
104211090.004.png 104211090.005.png
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V CC ) .............................................................12V
Control Input Voltage (R —– , DE)...................-0.5V to (V CC + 0.5V)
Driver Input Voltage (DI).............................-0.5V to (V CC + 0.5V)
Driver Output Voltage (A, B)...................................-8V to +12.5V
Receiver Input Voltage (A, B).................................-8V to +12.5V
Receiver Output Voltage (RO).....................-0.5V to (V CC +0.5V)
Continuous Power Dissipation (T A = +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ....727mW
14-Pin Plastic DIP (derate 10.00mW/°C above +70°C) ..800mW
8-Pin SO (derate 5.88mW/°C above +70°C).................471mW
14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW
8-Pin µMAX (derate 4.1mW/°C above +70°C) ..............830mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C).........640mW
14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mW
Operating Temperature Ranges
MAX4_ _C_ _/MAX1487C_ A ...............................0°C to +70°C
MAX4_ _E_ _/MAX1487E_ A .............................-40°C to +85°C
MAX4_ _MJ_/MAX1487MJA ...........................-55°C to +125°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+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.
DC ELECTRICAL CHARACTERISTICS
(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Differential Driver Output (no load)
V OD1
5
V
Differential Driver Output
(with load)
V OD2
R = 50
½
(RS-422)
2
V
R = 27 ½
(RS-485), Figure 4
1.5
5
Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
Æ V OD
R = 27 ½
or 50 ½ , Figure 4
0.2
V
Driver Common-Mode Output
Voltage
V OC
R = 27
½
or 50
½
, Figure 4
3
V
Change in Magnitude of Driver
Common-Mode Output Voltage
for Complementary Output States
V OD
R = 27
½
or 50
½
, Figure 4
0.2
V
DE, DI, R —–
Input High Voltage
V IH
2.0
V
DE, DI, R —–
Input Low Voltage
V IL
0.8
V
DE, DI, R —–
Input Current
I IN1
±2
µA
DE = 0V;
V CC = 0V or 5.25V,
all devices except
MAX487/MAX1487
V IN = 12V
1.0
mA
Input Current
(A, B)
I IN2
V IN = -7V
-0.8
MAX487/MAX1487,
DE = 0V, V CC = 0V or 5.25V
V IN = 12V
0.25
mA
V IN = -7V
-0.2
Receiver Differential Threshold
Voltage
V TH
-7V ²
V CM ²
12V
-0.2
0.2
V
Receiver Input Hysteresis
Æ V TH
V CM = 0V
70
mV
Receiver Output High Voltage
V OH
I O = -4mA, V ID = 200mV
3.5
V
Receiver Output Low Voltage
V OL
I O = 4mA, V ID = -200mV
0.4
V
Three-State (high impedance)
Output Current at Receiver
I OZR
0.4V
²
V O
²
2.4V
±1
µA
12V, all devices except
MAX487/MAX1487
²
V CM
²
12
k
½
Receiver Input Resistance
R IN
-7V ²
V CM ²
12V, MAX487/MAX1487
48
k ½
2 _______________________________________________________________________________________
Æ
-7V
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Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
DC ELECTRICAL CHARACTERISTICS (continued)
(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX488/MAX489,
DE, DI, R —– = 0V or V CC
120
250
MAX490/MAX491,
DE, DI, R —– = 0V or V CC
300
500
No-Load Supply Current
(Note 3)
MAX481/MAX485,
R —– = 0V or V CC
DE = V CC
500
900
I CC
DE = 0V
DE = V CC
DE = 0V
300
500
µA
MAX1487,
R —– = 0V or V CC
300
500
230
400
MAX483/MAX487,
R —– = 0V or V CC
DE = 5V
MAX483
MAX487
350
650
250
400
DE = 0V
120
250
MAX481/483/487, DE = 0V, R —– = V CC
Supply Current in Shutdown
I SHDN
0.1
10
µA
Driver Short-Circuit Current,
V O = High
I OSD1
-7V
²
V O
²
12V (Note 4)
35
250
mA
Driver Short-Circuit Current,
V O = Low
I OSD2
-7V
²
V O
²
12V (Note 4)
35
250
mA
Receiver Short-Circuit Current
I OSR
0V
²
V O
²
V CC
7
95
mA
SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487
(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Driver Input to Output
t PLH
Figures 6 and 8, R DIFF = 54
½
,
10
30
60
ns
t PHL
C L1 = C L2 = 100pF
10
30
60
Driver Output Skew to Output
t SKEW
Figures 6 and 8, R DIFF = 54
½
, C L1 = C L2 = 100pF
5
10
ns
Figures 6 and 8,
R DIFF = 54
MAX481, MAX485, MAX1487
3
15
40
Driver Rise or Fall Time
t R , t F
,
C L1 = C L2 = 100pF
½
MAX490C/E, MAX491C/E
5
15
25
ns
MAX490M, MAX491M
3
15
40
Driver Enable to Output High
t ZH
Figures 7 and 9, C L = 100pF, S2 closed
Figures 7 and 9, C L = 100pF, S1 closed
Figures 7 and 9, C L = 15pF, S1 closed
Figures 7 and 9, C L = 15pF, S2 closed
40
70
ns
Driver Enable to Output Low
t ZL
40
70
ns
Driver Disable Time from Low
t LZ
40
70
ns
Driver Disable Time from High
t HZ
40
70
ns
Figures 6 and 10,
R DIFF = 54
MAX481, MAX485, MAX1487
20
90
200
Receiver Input to Output
t PLH , t PHL
,
C L1 = C L2 = 100pF
½
MAX490C/E, MAX491C/E
20
90
150
ns
MAX490M, MAX491M
20
90
200
| t PLH - t PHL | Differential
Receiver Skew
t SKD
Figures 6 and 10, R DIFF = 54
½
,
13
ns
C L1 = C L2 = 100pF
Receiver Enable to Output Low
t ZL
Figures 5 and 11, C RL = 15pF, S1 closed
20
50
ns
Receiver Enable to Output High
t ZH
Figures 5 and 11, C RL = 15pF, S2 closed
20
50
ns
Receiver Disable Time from Low
t LZ
Figures 5 and 11, C RL = 15pF, S1 closed
20
50
ns
Receiver Disable Time from High
t HZ
Figures 5 and 11, C RL = 15pF, S2 closed
20
50
ns
Maximum Data Rate
f MAX
2.5
Mbps
Time to Shutdown
t SHDN
MAX481 (Note 5)
50
200
600
ns
_______________________________________________________________________________________ 3
104211090.007.png 104211090.001.png
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (continued)
(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Driver Enable from Shutdown to
Output High (MAX481)
t ZH(SHDN)
Figures 7 and 9, C L = 100pF, S2 closed
40
100
ns
Driver Enable from Shutdown to
Output Low (MAX481)
t ZL(SHDN)
Figures 7 and 9, C L = 100pF, S1 closed
40
100
ns
Receiver Enable from Shutdown
to Output High (MAX481)
t ZH(SHDN)
Figures 5 and 11, C L = 15pF, S2 closed,
A - B = 2V
300
1000
ns
Receiver Enable from Shutdown
to Output Low (MAX481)
t ZL(SHDN)
Figures 5 and 11, C L = 15pF, S1 closed,
B - A = 2V
300
1000
ns
SWITCHING CHARACTERISTICS—MAX483, MAX487/MAX488/MAX489
(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Driver Input to Output
t PLH
Figures 6 and 8, R DIFF = 54
½
,
250
800
2000
ns
t PHL
C L1 = C L2 = 100pF
250
800
2000
Driver Output Skew to Output
t SKEW
Figures 6 and 8, R DIFF = 54 ½ ,
C L1 = C L2 = 100pF
100
800
ns
Driver Rise or Fall Time
t R , t F
Figures 6 and 8, R DIFF = 54 ½ ,
C L1 = C L2 = 100pF
250
2000
ns
Driver Enable to Output High
t ZH
Figures 7 and 9, C L = 100pF, S2 closed
250
2000
ns
Driver Enable to Output Low
t ZL
Figures 7 and 9, C L = 100pF, S1 closed
250
2000
ns
Driver Disable Time from Low
t LZ
Figures 7 and 9, C L = 15pF, S1 closed
300
3000
ns
Driver Disable Time from High
t HZ
Figures 7 and 9, C L = 15pF, S2 closed
300
3000
ns
Receiver Input to Output
t PLH
Figures 6 and 10, R DIFF = 54
½
,
250
2000
ns
t PHL
C L1 = C L2 = 100pF
250
2000
I t PLH - t PHL I Differential
Receiver Skew
t SKD
Figures 6 and 10, R DIFF = 54
½
,
100
ns
C L1 = C L2 = 100pF
Receiver Enable to Output Low
t ZL
Figures 5 and 11, C RL = 15pF, S1 closed
20
50
ns
Receiver Enable to Output High
t ZH
Figures 5 and 11, C RL = 15pF, S2 closed
20
50
ns
Receiver Disable Time from Low
t LZ
Figures 5 and 11, C RL = 15pF, S1 closed
20
50
ns
Receiver Disable Time from High
t HZ
Figures 5 and 11, C RL = 15pF, S2 closed
20
50
ns
Maximum Data Rate
f MAX
t PLH , t PHL < 50% of data period
250
kbps
Time to Shutdown
t SHDN
MAX483/MAX487 (Note 5)
50
200
600
ns
Driver Enable from Shutdown to
Output High
t ZH(SHDN)
MAX483/MAX487, Figures 7 and 9,
C L = 100pF, S2 closed
2000
ns
Driver Enable from Shutdown to
Output Low
t ZL(SHDN)
MAX483/MAX487, Figures 7 and 9,
C L = 100pF, S1 closed
2000
ns
Receiver Enable from Shutdown
to Output High
t ZH(SHDN)
MAX483/MAX487, Figures 5 and 11,
C L = 15pF, S2 closed
2500
ns
Receiver Enable from Shutdown
to Output Low
t ZL(SHDN)
MAX483/MAX487, Figures 5 and 11,
C L = 15pF, S1 closed
2500
ns
4 _______________________________________________________________________________________
104211090.002.png
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICS
Note 1: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device
ground unless otherwise specified.
Note 2: All typical specifications are given for V CC = 5V and T A = +25°C.
Note 3: Supply current specification is valid for loaded transmitters when DE = 0V.
Note 4: Applies to peak current. See Typical Operating Characteristics.
Note 5: The MAX481/MAX483/MAX487 are put into shutdown by bringing R —– high and DE low. If the inputs are in this state for less
than 50ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts are
guaranteed to have entered shutdown. See Low-Power Shutdown Modesection.
__________________________________________Typical Operating Characteristics
(V CC = 5V, T A = +25°C, unless otherwise noted.)
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
RECEIVER OUTPUT HIGH VOLTAGE vs.
TEMPERATURE
45
-20
4.8
40
-18
4.6
I RO = 8mA
35
-16
4.4
30
-14
4.2
-12
25
4.0
-10
20
-8
3.8
15
10
-6
3.6
-4
3.4
5
-2
0
3.2
0
3.0
0
0.5
1.0
1.5
2.0
2.5
1.5 2.0
2.5
3.0
3.5
4.0
4.5
5.0
-50 -25
0
25
50
75
100 125
OUTPUT LOW VOLTAGE (V)
OUTPUT HIGH VOLTAGE (V)
TEMPERATURE (°C)
RECEIVER OUTPUT LOW VOLTAGE vs.
TEMPERATURE
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
0.9
90
2.4
0.8
I RO = 8mA
80
2.3
R = 54 W
0.7
70
2.2
0.6
60
2.1
0.5
50
2.0
0.4
40
1.9
0.3
30
1.8
0.2
20
1.7
0.1
10
1.6
0
0
1.5
-50 -25
0
25
50
75
100 125
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
-50 -25
0
25
50
75
100
125
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
_______________________________________________________________________________________ 5
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