MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
LE
AVAILAB
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
General Description
The MAX481E, MAX483E, MAX485E, MAX487E–
MAX491E, and MAX1487E are low-power transceivers for
RS-485 and RS-422 communications in harsh environments. Each driver output and receiver input is protected
against ±15kV electro-static discharge (ESD) shocks,
without latchup. These parts contain one driver and one
receiver. The MAX483E, MAX487E, MAX488E, and
MAX489E 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 MAX481E,
MAX485E, MAX490E, MAX491E, and MAX1487E are not
limited, allowing them to transmit up to 2.5Mbps.
These transceivers draw as little as 120µA supply current when unloaded or when fully loaded with disabled
drivers (see Selector Guide). Additionally, the MAX481E,
MAX483E, and MAX487E have a low-current shutdown
mode in which they consume only 0.5µA. 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 their 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.
The MAX487E and MAX1487E feature quarter-unit-load
receiver input impedance, allowing up to 128 transceivers on the bus. The MAX488E–MAX491E are
designed for full-duplex
communications,
while the
Functional
Diagrams
MAX481E, MAX483E, MAX485E, MAX487E, and
MAX1487E are designed for half-duplex applications.
For applications that are not ESD sensitive see the pinand function-compatible MAX481, MAX483, MAX485,
MAX487–MAX491, and MAX1487.
Next-Generation Device Features
♦ For Fault-Tolerant Applications:
MAX3430: ±80V Fault-Protected, Fail-Safe, 1/4Unit Load, +3.3V, RS-485 Transceiver
MAX3080–MAX3089: Fail-Safe, High-Speed
(10Mbps), Slew-Rate-Limited, RS-485/RS-422
Transceivers
♦ For Space-Constrained Applications:
MAX3460–MAX3464: +5V, Fail-Safe, 20Mbps,
Profibus, RS-485/RS-422 Transceivers
MAX3362: +3.3V, High-Speed, RS-485/RS-422
Transceiver in a SOT23 Package
MAX3280E–MAX3284E: ±15kV ESD-Protected,
52Mbps, +3V to +5.5V, SOT23, RS-485/RS-422
True Fail-Safe Receivers
MAX3030E–MAX3033E: ±15kV ESD-Protected,
+3.3V, Quad RS-422 Transmitters
♦ For Multiple Transceiver Applications:
MAX3293/MAX3294/MAX3295: 20Mbps, +3.3V,
SOT23, RS-485/RS-422 Transmitters
♦ For Fail-Safe Applications:
MAX3440E–MAX3444E: ±15kV ESD-Protected,
±60V Fault-Protected, 10Mbps, Fail-Safe
RS-485/J1708 Transceivers
♦ For Low-Voltage Applications:
MAX3483E/MAX3485E/MAX3486E/MAX3488E/
MAX3490E/MAX3491E: +3.3V Powered, ±15kV
ESD-Protected, 12Mbps, Slew-Rate-Limited,
True RS-485/RS-422 Transceivers
Ordering Information
Applications
Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
PART
MAX481ECPA
TEMP RANGE
0°C to +70°C
PIN-PACKAGE
8 Plastic DIP
MAX481ECSA
0°C to +70°C
Level Translators
MAX481EEPA
-40°C to +85°C
8 Plastic DIP
Transceivers for EMI-Sensitive Applications
MAX481EESA
-40°C to +85°C
8 SO
Industrial-Control Local Area Networks
MAX483ECPA
0°C to +70°C
MAX483ECSA
0°C to +70°C
MAX483EEPA
-40°C to +85°C
8 Plastic DIP
MAX483EESA
-40°C to +85°C
8 SO
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
8 SO
8 Plastic DIP
8 SO
Ordering Information continued at end of data sheet.
Selector Guide appears at end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-0410; Rev 4; 10/03
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC) .............................................................12V
–—–
Control Input Voltage (RE , DE)...................-0.5V to (VCC + 0.5V)
Driver Input Voltage (DI).............................-0.5V to (VCC + 0.5V)
Driver Output Voltage (Y, Z; A, B) ..........................-8V to +12.5V
Receiver Input Voltage (A, B).................................-8V to +12.5V
Receiver Output Voltage (RO)....................-0.5V to (VCC + 0.5V)
Continuous Power Dissipation (TA = +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
Operating Temperature Ranges
MAX4_ _C_ _/MAX1487EC_ A .............................0°C to +70°C
MAX4_ _E_ _/MAX1487EE_ A...........................-40°C to +85°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
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
Differential Driver Output (no load)
VOD1
Differential Driver Output
(with load)
VOD2
Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
Driver Common-Mode Output
Voltage
Change in Magnitude of Driver
Common-Mode Output Voltage
for Complementary Output States
MIN
R = 50Ω (RS-422)
TYP
MAX
UNITS
5
V
2
R = 27Ω (RS-485), Figure 8
1.5
5
R = 27Ω or 50Ω, Figure 8
0.2
V
VOC
R = 27Ω or 50Ω, Figure 8
3
V
ΔVOD
R = 27Ω or 50Ω, Figure 8
0.2
V
Input Low Voltage
VIL
Input Current
IIN1
VIN = 12V
1.0
IIN2
DE = 0V;
VCC = 0V or 5.25V,
all devices except
MAX487E/MAX1487E
VIN = -7V
-0.8
MAX487E/MAX1487E,
DE = 0V, VCC = 0V or 5.25V
VIN = 12V
0.25
VIN = -7V
-0.2
Input Current
(A, B)
Receiver Differential Threshold
Voltage
V
ΔVOD
–—–
DE, DI, RE
–—–
DE, DI, RE
–—–
DE, DI, RE
Input High Voltage
VIH
VTH
2.0
V
0.8
V
±2
µA
mA
-7V ≤ VCM ≤ 12V
-0.2
0.2
mA
V
Receiver Input Hysteresis
ΔVTH
VCM = 0V
Receiver Output High Voltage
VOH
IO = -4mA, VID = 200mV
Receiver Output Low Voltage
VOL
IO = 4mA, VID = -200mV
0.4
V
Three-State (high impedance)
Output Current at Receiver
IOZR
0.4V ≤ VO ≤ 2.4V
±1
µA
Receiver Input Resistance
2
CONDITIONS
70
mV
3.5
V
-7V ≤ VCM ≤ 12V, all devices except
MAX487E/MAX1487E
12
kΩ
-7V ≤ VCM ≤ 12V, MAX487E/MAX1487E
48
kΩ
RIN
Maxim Integrated
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
No-Load Supply Current
(Note 3)
SYMBOL
ICC
TYP
MAX
MAX488E/MAX489E,
–—–
DE, DI, RE = 0V or VCC
CONDITIONS
MIN
120
250
MAX490E/MAX491E,
–—–
DE, DI, RE = 0V or VCC
300
500
UNITS
MAX481E/MAX485E,
–—–
RE = 0V or VCC
DE = VCC
500
900
DE = 0V
300
500
MAX1487E,
–—–
RE = 0V or VCC
DE = VCC
300
500
DE = 0V
230
400
MAX483E
350
650
MAX487E
250
120
0.5
400
250
10
µA
MAX483E/MAX487E,
–—–
RE = 0V or VCC
DE = VCC
µA
Supply Current in Shutdown
ISHDN
DE = 0V
–—–
MAX481E/483E/487E, DE = 0V, RE = VCC
Driver Short-Circuit Current,
VO = High
IOSD1
-7V ≤ VO ≤12V (Note 4)
35
250
mA
Driver Short-Circuit Current,
VO = Low
IOSD2
-7V ≤ VO ≤12V (Note 4)
35
250
mA
IOSR
0V ≤ VO ≤ VCC
A, B, Y and Z pins, tested using Human Body Model
7
95
mA
kV
Receiver Short-Circuit Current
ESD Protection
±15
SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
Driver Input to Output
tPLH
tPHL
Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF
Driver Output Skew to Output
tSKEW
Figures 10 and 12, RDIFF = 54Ω, CL1 = CL2 = 100pF
Driver Rise or Fall Time
tR, tF
Figures 10 and 12, MAX481E, MAX485E, MAX1487E
RDIFF = 54Ω,
CL1 = CL2 = 100pF MAX490EC/E, MAX491EC/E
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
Receiver Input to Output
| tPLH - tPHL | Differential
Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
Maximum Data Rate
Time to Shutdown
Maxim Integrated
tZH
tZL
tLZ
tHZ
MIN
TYP
MAX
10
10
40
40
5
60
60
10
3
20
40
5
20
25
45
45
45
45
70
70
70
70
20
60
200
20
60
150
Figures 10 and 14, RDIFF = 54Ω,
CL1 = CL2 = 100pF
5
tZL
tZH
tLZ
tHZ
Figures 9 and 15, CRL = 15pF, S1 closed
Figures 9 and 15, CRL = 15pF, S2 closed
Figures 9 and 15, CRL = 15pF, S1 closed
Figures 9 and 15, CRL = 15pF, S2 closed
20
20
20
20
50
50
50
50
200
600
MAX481E (Note 5)
ns
ns
ns
ns
ns
ns
tSKD
fMAX
tSHDN
ns
ns
Figures 11 and 13, CL = 100pF, S2 closed
Figures 11 and 13, CL = 100pF, S1 closed
Figures 11 and 13, CL = 15pF, S1 closed
Figures 11 and 13, CL = 15pF, S2 closed
Figures 10 and 14, MAX481E, MAX485E, MAX1487E
tPLH, tPHL RDIFF = 54Ω,
CL1 = CL2 = 100pF MAX490EC/E, MAX491EC/E
UNITS
2.5
50
ns
ns
ns
ns
ns
Mbps
ns
3
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E
(continued)
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Driver Enable from Shutdown to
tZH(SHDN)
Output High (MAX481E)
Figures 11 and 13, CL = 100pF, S2 closed
45
100
ns
Driver Enable from Shutdown to
tZL(SHDN)
Output Low (MAX481E)
Figures 11 and 13, CL = 100pF, S1 closed
45
100
ns
Receiver Enable from Shutdown
tZH(SHDN)
to Output High (MAX481E)
Figures 9 and 15, CL = 15pF, S2 closed,
A - B = 2V
225
1000
ns
Receiver Enable from Shutdown
tZL(SHDN)
to Output Low (MAX481E)
Figures 9 and 15, CL = 15pF, S1 closed,
B - A = 2V
225
1000
ns
UNITS
SWITCHING CHARACTERISTICS—MAX483E, MAX487E/MAX488E/MAX489E
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
Driver Input to Output
tPHL
CONDITIONS
Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF
MIN
250
TYP
800
MAX
2000
250
800
2000
20
800
ns
ns
Driver Output Skew to Output
tSKEW
Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF
Driver Rise or Fall Time
tR, tF
Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF
250
2000
ns
Driver Enable to Output High
tZH
Figures 11 and 13, CL = 100pF, S2 closed
250
2000
ns
Driver Enable to Output Low
tZL
Figures 11 and 13, CL = 100pF, S1 closed
250
2000
ns
Driver Disable Time from Low
tLZ
Figures 11 and 13, CL = 15pF, S1 closed
300
3000
ns
Driver Disable Time from High
tHZ
Figures 11 and 13, CL = 15pF, S2 closed
300
3000
ns
Figures 10 and 14, RDIFF = 54Ω,
CL1 = CL2 = 100pF
250
2000
250
2000
Receiver Input to Output
I tPLH - tPHL I Differential
Receiver Skew
tPLH
tPHL
tSKD
Figures 10 and 14, RDIFF = 54Ω,
CL1 = CL2 = 100pF
100
ns
ns
Receiver Enable to Output Low
tZL
Figures 9 and 15, CRL = 15pF, S1 closed
25
50
ns
Receiver Enable to Output High
tZH
Figures 9 and 15, CRL = 15pF, S2 closed
25
50
ns
Receiver Disable Time from Low
tLZ
Figures 9 and 15, CRL = 15pF, S1 closed
25
50
ns
tHZ
Figures 9 and 15, CRL = 15pF, S2 closed
25
50
Receiver Disable Time from High
Maximum Data Rate
fMAX
tPLH, tPHL < 50% of data period
250
Time to Shutdown
tSHDN
MAX483E/MAX487E (Note 5)
50
Driver Enable from Shutdown to
Output High
Driver Enable from Shutdown to
Output Low
Receiver Enable from Shutdown
to Output High
Receiver Enable from Shutdown
to Output Low
4
SYMBOL
tPLH
tZH(SHDN)
tZL(SHDN)
tZH(SHDN)
tZL(SHDN)
MAX483E/MAX487E, Figures 11 and 13,
CL = 100pF, S2 closed
MAX483E/MAX487E, Figures 11 and 13,
CL = 100pF, S1 closed
MAX483E/MAX487E, Figures 9 and 15,
CL = 15pF, S2 closed
MAX483E/MAX487E, Figures 9 and 15,
CL = 15pF, S1 closed
ns
kbps
200
600
ns
2000
ns
2000
ns
2500
ns
2500
ns
Maxim Integrated
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, 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 VCC = 5V and TA = +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 MAX481E/MAX483E/MAX487E are put into shutdown by bringing RE 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 Mode section.
__________________________________________Typical Operating Characteristics
(VCC = 5V, TA = +25°C, unless otherwise noted.)
35
30
25
20
15
-15
-10
10
4.8
MAX481E-02
-20
OUTPUT CURRENT (mA)
40
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
4.6
OUTPUT HIGH VOLTAGE (V)
45
OUTPUT CURRENT (mA)
-25
MAX481E-01
50
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
-5
IRO = 8mA
MAX481E-03
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
4.4
4.2
4.0
3.8
3.6
3.4
3.2
5
0
0
0
0.5
1.0
1.5
2.0
2.5
3.0
1.5
2.0
OUTPUT LOW VOLTAGE (V)
2.5
3.0
3.5
4.0
4.5
OUTPUT HIGH VOLTAGE (V)
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
0.7
0.6
0.5
0.4
0.3
80
40
60
80 100
70
60
50
40
30
0.2
20
0.1
10
0
0
-60 -40 -20
0
20
40
60
TEMPERATURE (°C)
Maxim Integrated
20
MAX481E-05
IRO = 8mA
0
TEMPERATURE (°C)
90
OUTPUT CURRENT (mA)
OUTPUT LOW VOLTAGE (V)
0.8
-60 -40 -20
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
MAX481E-04
0.9
5.0
80 100
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
DIFFERENTIAL OUTPUT VOLTAGE (V)
5
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
____________________________Typical Operating Characteristics (continued)
(VCC = 5V, TA = +25°C, unless otherwise noted.)
OUTPUT CURRENT vs.
DRIVER OUTPUT LOW VOLTAGE
2.0
1.9
1.8
1.7
80
60
40
-80
-70
-60
-50
-40
-30
-20
20
1.5
0
0
20
60
40
0
2
4
6
8
10
12
-8
-6
-4
0
-2
2
4
TEMPERATURE (°C)
OUTPUT LOW VOLTAGE (V)
OUTPUT HIGH VOLTAGE (V)
MAX481E/MAX485E/MAX490E/MAX491E
SUPPLY CURRENT vs. TEMPERATURE
MAX483E/MAX487E–MAX489E
SUPPLY CURRENT vs. TEMPERATURE
MAX1487E
SUPPLY CURRENT vs. TEMPERATURE
500
600
500
300
MAX485E; DE = 0, RE = X,
MAX481E; DE = RE = 0
MAX490E/MAX491E; DE = RE = X
100
400
300
200
SUPPLY CURRENT (μA)
SUPPLY CURRENT (μA)
500
400
MAX483E; DE = VCC, RE = X
MAX487E; DE = VCC, RE = X
MAX483E/MAX487E; DE = RE = 0,
MAX488E/MAX489E; DE = RE = X
40
60
TEMPERATURE (°C)
200
MAX1487E; DE = 0V, RE = X
0
0
20
MAX1487E; DE = VCC, RE = X
300
MAX483E/MAX487E; DE = 0, RE = VCC
0
0
400
100
100
MAX481E; DE = 0, RE = VCC
-60 -40 -20
6
MAX481E-11
600
MAX481E-10
MAX481E/MAX485E; DE = VCC, RE = X
200
-10
0
80 100
600
SUPPLY CURRENT (μA)
100
1.6
-60 -40 -20
6
-90
OUTPUT CURRENT (mA)
120
OUTPUT CURRENT (mA)
2.1
-100
MAX481E-07
140
MAX481E-06
R = 54Ω
2.2
MAX481E-09
DIFFERENTIAL OUTPUT VOLTAGE (V)
2.3
OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
MAX481E-08
DRIVER DIFFERENTIAL OUTPUT
VOLTAGE vs. TEMPERATURE
80 100
-60 -40 -20
0
20
40
60
TEMPERATURE (°C)
80 100
-60 -40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
Maxim Integrated
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
______________________________________________________________Pin Description
PIN
MAX481E/MAX483E
MAX485E/MAX487E
MAX1487E
MAX488E
MAX490E
MAX489E
MAX491E
NAME
1
2
2
RO
2
—
3
–—–
RE
FUNCTION
Receiver Output: If A > B by 200mV, RO will be high;
If A < B by 200mV, RO will be low.
–—–
Receiver Output Enable. RO is enabled when RE is
–—–
low; RO is high impedance when RE is high.
3
—
4
DE
Driver Output Enable. The driver outputs, Y and Z, are
enabled by bringing DE high. They are high impedance when DE is low. If the driver outputs are enabled,
the parts function as line drivers. While they are high
–—–
impedance, they function as line receivers if R E is low.
4
3
5
DI
Driver Input. A low on DI forces output Y low and output Z high. Similarly, a high on DI forces output Y high
and output Z low.
5
4
6, 7
GND
—
5
9
Y
Noninverting Driver Output
—
6
10
Z
Inverting Driver Output
6
—
—
A
Noninverting Receiver Input and Noninverting Driver
Output
—
8
12
A
Noninverting Receiver Input
7
—
—
B
Inverting Receiver Input and Inverting Driver Output
—
7
11
B
Inverting Receiver Input
8
1
14
VCC
Positive Supply: 4.75V ≤ VCC ≤ 5.25V
—
—
1, 8, 13
N.C.
No Connect—not internally connected
Maxim Integrated
Ground
7
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
0.1μF
TOP VIEW
RO
1
R
8
RO
VCC
1
RE 2
7
B
RE 2
DE 3
6
A
DE 3
5
GND
DI 4
DI 4
D
R
8 VCC
7 B
Rt
6
A
5 GND
D
MAX481E
MAX483E
MAX485E
MAX487E
MAX1487E
DE
DI
D
B
Rt
A
RO
R
RE
DIP/SO
NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.
TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.
Figure 1. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Pin Configuration and Typical Operating Circuit
0.1μF
VCC
MAX488E
MAX490E
VCC 1
5 Y
TOP VIEW
8
A
RO 2
7
B
DI 3
6
Z
VCC 1
GND 4
R
5
D
DI
3
Rt
D
6 Z
R
RO
8 A
RO
Y
2
Rt
R
D
7
DI
B
DIP/SO
4 GND
GND
NOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.
Figure 2. MAX488E/MAX490E Pin Configuration and Typical Operating Circuit
DE
4
TOP VIEW
N.C. 1
RO 2
R
13 N.C.
12 A
DE 4
11 B
DI 5
10 Z
D
GND 7
9
Y
8
N.C.
9
DI
5
MAX489E
MAX491E
Y
Rt
D
10
RO
R
Z
12
RO
2
R
A
Rt
D
11
DI
B
NC
1, 8, 13
3
DIP/SO
VCC RE
0.1μF
14
14 V CC
RE 3
GND 6
VCC
6, 7 GND
RE
GND
DE
Figure 3. MAX489E/MAX491E Pin Configuration and Typical Operating Circuit
8
Maxim Integrated
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
__________Function Tables (MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E)
Table 1. Transmitting
Table 2. Receiving
INPUTS
OUTPUTS
INPUTS
OUTPUT
RE
DE
DI
Z
Y
RE
DE
A-B
RO
X
1
1
0
1
0
0
> +0.2V
1
X
1
0
1
0
0
0
< -0.2V
0
0
0
X
High-Z
High-Z
0
0
Inputs open
1
1
0
X
High-Z*
High-Z*
1
0
X
High-Z*
X = Don't care
High-Z = High impedance
* Shutdown mode for MAX481E/MAX483E/MAX487E
__________Applications Information
The MAX481E/MAX483E/MAX485E/MAX487E–MAX491E
and MAX1487E are low-power transceivers for RS-485
and RS-422 communications. These “E” versions of the
MAX481, MAX483, MAX485, MAX487–MAX491, and
MAX1487 provide extra protection against ESD. The
rugged MAX481E, MAX483E, MAX485E, MAX497E–
MAX491E, and MAX1487E are intended for harsh environments where high-speed communication is important.
These devices eliminate the need for transient suppressor diodes and the associated high capacitance loading.
The standard (non-“E”) MAX481, MAX483, MAX485,
MAX487–MAX491, and MAX1487 are recommended for
applications where cost is critical.
The MAX481E, MAX485E, MAX490E, MAX491E, and
MAX1487E can transmit and receive at data rates up to
2.5Mbps, while the MAX483E, MAX487E, MAX488E,
and MAX489E are specified for data rates up to
250kbps. The MAX488E–MAX491E are full-duplex
transceivers, while the MAX481E, MAX483E, MAX487E,
and MAX1487E are half-duplex. In addition, driverenable (DE) and receiver-enable (RE) pins are included
on the MAX481E, MAX483E, MAX485E, MAX487E,
MAX489E, MAX491E, and MAX1487E. When disabled,
the driver and receiver outputs are high impedance.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electrostatic discharges encountered during handling and
assembly. The driver outputs and receiver inputs have
extra protection against static electricity. Maxim’s engi-
Maxim Integrated
X = Don't care
High-Z = High impedance
* Shutdown mode for MAX481E/MAX483E/MAX487E
neers developed state-of-the-art structures to protect
these pins against ESD of ±15kV without damage. The
ESD structures withstand high ESD in all states: normal
operation, shutdown, and powered down. After an ESD
event, Maxim’s MAX481E, MAX483E, MAX485E,
MAX487E–MAX491E, and MAX1487E keep working
without latchup.
ESD protection can be tested in various ways; the
transmitter outputs and receiver inputs of this product
family are characterized for protection to ±15kV using
the Human Body Model.
Other ESD test methodologies include IEC10004-2 contact discharge and IEC1000-4-2 air-gap discharge (formerly IEC801-2).
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test set-up, test methodology, and test results.
Human Body Model
Figure 4 shows the Human Body Model, and Figure 5
shows the current waveform it generates when discharged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the test device
through a 1.5kΩ resistor.
IEC1000-4-2
The IEC1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically
refer to integrated circuits (Figure 6).
9
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
R C 1M
CHARGE CURRENT
LIMIT RESISTOR
HIGH
VOLTAGE
DC
SOURCE
Cs
100pF
R D 1500Ω
IP 100%
90%
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Ir
AMPERES
36.8%
10%
0
0
Figure 4. Human Body ESD Test Model
TIME
tRL
tDL
CURRENT WAVEFORM
Figure 5. Human Body Model Current Waveform
I
100%
CHARGE CURRENT
LIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
150pF
R D 330Ω
90%
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
I PEAK
R C 50M to 100M
DEVICE
UNDER
TEST
10%
t r = 0.7ns to 1ns
t
30ns
60ns
Figure 6. IEC1000-4-2 ESD Test Model
Figure 7. IEC1000-4-2 ESD Generator Current Waveform
Y
TEST POINT
RECEIVER
OUTPUT
CRL
15pF
R
VOD
R
1k
VCC
S1
1k
VOC
S2
Z
Figure 8. Driver DC Test Load
10
Figure 9. Receiver Timing Test Load
Maxim Integrated
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
3V
DE
CL1
Y
DI
A
RDIFF
VID
OUTPUT
UNDER TEST
B
Z
RE
CL
CL2
S2
Figure 10. Driver/Receiver Timing Test Circuit
Figure 11. Driver Timing Test Load
3V
3V
DI
1.5V
0V
DE
1.5V
1.5V
1.5V
0V
tPHL
tPLH
1/2 VO
tZL(SHDN), tZL
Z
tLZ
Y, Z
VO
2.3V OUTPUT NORMALLY LOW
VOL
Y
1/2 VO
VO
VDIFF 0V
-VO
VCC
S1
500Ω
RO
10%
VDIFF = V (Y) - V (Z)
VOH -0.5V
2.3V
90%
tR
OUTPUT NORMALLY HIGH
Y, Z
90%
0V
10%
VOL +0.5V
tZH(SHDN), tZH
tF
tHZ
tSKEW = | tPLH - tPHL |
Figure 12. Driver Propagation Delays
Figure 13. Driver Enable and Disable Times (except MAX488E
and MAX490E)
3V
RE
1.5V
1.5V
0V
RO
A-B
VOH
1.5V
VOL
tPHL
VID
-VID
OUTPUT
0V
1.5V
tPLH
INPUT
tZL(SHDN), tZL
VCC
RO
tLZ
1.5V OUTPUT NORMALLY LOW
0V
VOL + 0.5V
OUTPUT NORMALLY HIGH
RO
VOH - 0.5V
1.5V
0V
tZH(SHDN), tZH
Figure 14. Receiver Propagation Delays
Maxim Integrated
tHZ
Figure 15. Receiver Enable and Disable Times (except MAX488E
and MAX490E)
11
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
10dB/div
10dB/div
0Hz
500kHz/div
5MHz
Figure 16. Driver Output Waveform and FFT Plot of
MAX485E/MAX490E/MAX491E/MAX1487E Transmitting a
150kHz Signal
The major difference between tests done using the
Human Body Model and IEC1000-4-2 is higher peak
current in IEC1000-4-2, because series resistance is
lower in the IEC1000-4-2 model. Hence, the ESD withstand voltage measured to IEC1000-4-2 is generally
lower than that measured using the Human Body
Model. Figure 7 shows the current waveform for the 8kV
IEC1000-4-2 ESD contact-discharge test.
The air-gap test involves approaching the device with a
charged probe. The contact-discharge method connects
the probe to the device before the probe is energized.
Machine Model
The Machine Model for ESD tests all pins using a
200pF storage capacitor and zero discharge resistance. Its objective is to emulate the stress caused by
contact that occurs with handling and assembly during
manufacturing. Of course, all pins require this protection during manufacturing—not just inputs and outputs.
Therefore, after PC board assembly, the Machine Model
is less relevant to I/O ports.
MAX487E/MAX1487E:
128 Transceivers on the Bus
The 48kΩ, 1/4-unit-load receiver input impedance of the
MAX487E and MAX1487E allows up to 128 transceivers
on a bus, compared to the 1-unit load (12kΩ input
impedance) of standard RS-485 drivers (32 transceivers
maximum). Any combination of MAX487E/MAX1487E
and other RS-485 transceivers with a total of 32 unit
loads or less can be put on the bus. The MAX481E,
MAX483E, MAX485E, and MAX488E–MAX491E have
standard 12kΩ receiver input impedance.
12
0Hz
500kHz/div
5MHz
Figure 17. Driver Output Waveform and FFT Plot of
MAX483E/MAX487E–MAX489E Transmitting a 150kHz Signal
MAX483E/MAX487E/MAX488E/MAX489E:
Reduced EMI and Reflections
The MAX483E and MAX487E–MAX489E are slew-rate
limited, minimizing EMI and reducing reflections
caused by improperly terminated cables. Figure 16
shows the driver output waveform and its Fourier analysis of a 150kHz signal transmitted by a MAX481E,
MAX485E, MAX490E, MAX491E, or MAX1487E. Highfrequency harmonics with large amplitudes are evident.
Figure 17 shows the same information displayed for a
MAX483E, MAX487E, MAX488E, or MAX489E transmitting under the same conditions. Figure 17’s high-frequency harmonics have much lower amplitudes, and
the potential for EMI is significantly reduced.
Low-Power Shutdown Mode
(MAX481E/MAX483E/MAX487E)
A low-power shutdown mode is initiated by bringing
both RE high and DE low. The devices will not shut
down unless both the driver and receiver are disabled.
In shutdown, the devices typically draw only 0.5µA of
supply current.
RE and DE may be driven simultaneously; the parts are
guaranteed not to enter shutdown if RE is high and DE
is low for less than 50ns. If the inputs are in this state
for at least 600ns, the parts are guaranteed to enter
shutdown.
For the MAX481E, MAX483E, and MAX487E, the t ZH
and tZL enable times assume the part was not in the
low-power shutdown state (the MAX485E, MAX488E–
MAX491E, and MAX1487E can not be shut down). The
t ZH(SHDN) and t ZL(SHDN) enable times assume the
parts were shut down (see Electrical Characteristics).
Maxim Integrated
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
100pF
B
Z
TTL IN
tR, tF < 6ns
D
R
R = 54Ω
Y
RECEIVER
OUT
A
100pF
delay times. Typical propagation delays are shown in
Figures 19–22 using Figure 18’s test circuit.
The difference in receiver delay times, tPLH - tPHL, is
typically under 13ns for the MAX481E, MAX485E,
MAX490E, MAX491E, and MAX1487E, and is typically
less than 100ns for the MAX483E and MAX487E–
MAX489E.
The driver skew times are typically 5ns (10ns max) for
the MAX481E, MAX485E, MAX490E, MAX491E, and
MAX1487E, and are typically 100ns (800ns max) for the
MAX483E and MAX487E–MAX489E.
Typical Applications
Figure 18. Receiver Propagation Delay Test Circuit
It takes the drivers and receivers longer to become
enabled from the low-power shutdown state (tZH(SHDN),
tZL(SHDN)) than from the operating mode (tZH, tZL). (The
parts are in operating mode if the RE, DE inputs equal a
logical 0,1 or 1,1 or 0, 0.)
Driver Output Protection
Excessive output current and power dissipation caused
by faults or by bus contention are prevented by two
mechanisms. A foldback current limit on the output stage
provides immediate protection against short circuits over
the whole common-mode voltage range (see Typical
Operating Characteristics). In addition, a thermal shutdown circuit forces the driver outputs into a high-impedance state if the die temperature rises excessively.
Propagation Delay
Many digital encoding schemes depend on the difference between the driver and receiver propagation
Maxim Integrated
The MAX481E, MAX483E, MAX485E, MAX487E–
MAX491E, and MAX1487E transceivers are designed for
bidirectional data communications on multipoint bus
transmission lines. Figures 25 and 26 show typical network application circuits. These parts can also be used as
line repeaters, with cable lengths longer than 4000 feet.
To minimize reflections, the line should be terminated at
both ends in its characteristic impedance, and stub
lengths off the main line should be kept as short as possible. The slew-rate-limited MAX483E and MAX487E–
MAX489E are more tolerant of imperfect termination.
Bypass the VCC pin with 0.1µF.
Isolated RS-485
For isolated RS-485 applications, see the MAX253 and
MAX1480 data sheets.
Line Length vs. Data Rate
The RS-485/RS-422 standard covers line lengths up to
4000 feet. Figures 23 and 24 show the system differential voltage for the parts driving 4000 feet of 26AWG
twisted-pair wire at 110kHz into 100Ω loads.
13
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
A
B
500mV/div
500mV/div
B
A
RO
5V/div
5V/div
RO
25ns/div
25ns/div
Figure 19. MAX481E/MAX485E/MAX490E/MAX1487E Receiver
tPHL
Figure 20. MAX481E/MAX485E/MAX490E/MAX491E/
MAX1487E Receiver tPLH
A
B
500mV/div
500mV/div
B
A
RO
5V/div
5V/div
RO
200ns/div
200ns/div
Figure 21. MAX483E/MAX487E–MAX489E Receiver tPHL
DI
5V
Figure 22. MAX483E/MAX487E–MAX489E Receiver tPLH
DI
5V
0V
0V
1V
0
V A - VB
0
VB - VA
-1V
-1V
5V
DO
5V
0V
0V
2μs/div
Figure 23. MAX481E/MAX485E/MAX490E/MAX491E/
MAX1487E System Differential Voltage at 110kHz Driving
4000ft of Cable
14
DO
2μs/div
Figure 24. MAX483E/MAX1487E–MAX489E System Differential
Voltage at 110kHz Driving 4000ft of Cable
Maxim Integrated
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
120Ω
120Ω
DE
B
B
DI
D
D
DI
DE
B
A
A
B
A
A
R
R
RO
RE
RO
RE
R
R
D
D
MAX481E
MAX483E
MAX485E
MAX487E
MAX1487E
DE
DI
RO RE
DI
RO RE
DE
Figure 25. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Typical Half-Duplex RS-485 Network
A
R
RO
RE
Y
120Ω
120Ω
D
B
Z
Z
B
DE
DI
DE
DI
120Ω
D
Y
120Ω
Z
Y
B
A
Y
Z
R
A
DE RE RO
A
R
D
D
DI
B
R
RE
RO
DI
DE RE RO
MAX488E
MAX489E
MAX490E
MAX491E
NOTE: RE AND DE ON MAX489E/MAX491E ONLY.
Figure 26. MAX488E–MAX491E Full-Duplex RS-485 Network
Maxim Integrated
15
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
Ordering Information (continued)
PART
TEMP RANGE
PIN-PACKAGE
TEMP RANGE
PIN-PACKAGE
MAX485ECPA
0°C to +70°C
8 Plastic DIP
MAX489EEPD
PART
-40°C to +85°C
14 Plastic DIP
MAX485ECSA
0°C to +70°C
8 SO
MAX489EESD
-40°C to +85°C
14 SO
MAX485EEPA
-40°C to +85°C
8 Plastic DIP
MAX490ECPA
0°C to +70°C
8 Plastic DIP
MAX485EESA
-40°C to +85°C
8 SO
MAX490ECSA
0°C to +70°C
8 SO
MAX487ECPA
0°C to +70°C
8 Plastic DIP
MAX490EEPA
-40°C to +85°C
8 Plastic DIP
MAX487ECSA
0°C to +70°C
8 SO
MAX490EESA
-40°C to +85°C
8 SO
MAX487EEPA
-40°C to +85°C
8 Plastic DIP
MAX491ECPD
0°C to +70°C
MAX487EESA
-40°C to +85°C
8 SO
MAX491ECSD
0°C to +70°C
MAX488ECPA
0°C to +70°C
8 Plastic DIP
MAX491EEPD
-40°C to +85°C
14 Plastic DIP
-40°C to +85°C
14 SO
14 Plastic DIP
14 SO
MAX488ECSA
0°C to +70°C
8 SO
MAX491EESD
MAX488EEPA
-40°C to +85°C
8 Plastic DIP
MAX1487ECPA
0°C to +70°C
MAX488EESA
-40°C to +85°C
8 SO
MAX1487ECSA
0°C to +70°C
MAX489ECPD
0°C to +70°C
14 Plastic DIP
MAX1487EEPA
-40°C to +85°C
8 Plastic DIP
MAX489ECSD
0°C to +70°C
14 SO
MAX1487EESA
-40°C to +85°C
8 SO
8 Plastic DIP
8 SO
Selector Guide
HALF/FULL
DUPLEX
DATA
RATE
(Mbps)
SLEWRATE
LIMITED
LOW-POWER
SHUTDOWN
MAX481E
Half
2.5
No
Yes
MAX483E
Half
0.25
Yes
Yes
Yes
120
32
8
MAX485E
Half
2.5
No
No
Yes
300
32
8
MAX487E
Half
0.25
Yes
Yes
Yes
120
128
8
MAX488E
Full
0.25
Yes
No
No
120
32
8
MAX489E
Full
0.25
Yes
No
Yes
120
32
14
MAX490E
Full
2.5
No
No
No
300
32
8
MAX491E
Full
2.5
No
No
Yes
300
32
14
MAX1487E
Half
2.5
No
No
Yes
230
128
8
PART NUMBER
Chip Information
TRANSISTOR COUNT: 295
RECEIVER/ QUIESCENT
NUMBER OF
DRIVER
CURRENT TRANSMITTERS
ENABLE
(μA)
ON BUS
Yes
300
32
PIN
COUNT
8
Package Information
For the latest package outline information, go to
www.maxim-ic.com/packages.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
16
© Maxim Integrated
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.
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