AVAILABLE
Functional Diagrams
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.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
General Description
The MAX481E, MAX483E, MAX485E, MAX487E–
MAX491E, and MAX1487E are low-power transceivers for
RS-485 and RS-422 communications in harsh environ-
ments. 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 termi-
nated 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 cur-
rent 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 oper-
ate 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 guar-
antees 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 trans-
ceivers on the bus. The MAX488E–MAX491E are
designed for full-duplex communications, while the
MAX481E, MAX483E, MAX485E, MAX487E, and
MAX1487E are designed for half-duplex applications.
For applications that are not ESD sensitive see the pin-
and function-compatible MAX481, MAX483, MAX485,
MAX487–MAX491, and MAX1487.
Applications
Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
Next-Generation Device Features
♦For Fault-Tolerant Applications:
MAX3430: ±80V Fault-Protected, Fail-Safe, 1/4-
Unit 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
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
Ordering Information
PART TEMP RANGE PIN-PACKAGE
MAX481ECPA 0°C to +70°C 8 Plastic DIP
MAX481ECSA 0°C to +70°C 8 SO
MAX481EEPA -40°C to +85°C 8 Plastic DIP
MAX481EESA -40°C to +85°C 8 SO
MAX483ECPA 0°C to +70°C 8 Plastic DIP
MAX483ECSA 0°C to +70°C 8 SO
MAX483EEPA -40°C to +85°C 8 Plastic DIP
MAX483EESA -40°C to +85°C 8 SO
Ordering Information continued at end of data sheet.
Selector Guide appears at end of data sheet.
Ordering Information
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
Supply Voltage (VCC).............................................................12V
Control Input Voltage (–
R
—
E
–, 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
DC ELECTRICAL CHARACTERISTICS
(VCC = 5V ±5%, TA= TMIN to TMAX, unless otherwise noted.) (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.
ABSOLUTE MAXIMUM RATINGS
PARAMETER SYMBOL MIN TYP MAX UNITS
Driver Common-Mode Output
Voltage VOC 3 V
Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
ΔVOD 0.2 V
Change in Magnitude of Driver
Common-Mode Output Voltage
for Complementary Output States
ΔVOD 0.2 V
Input High Voltage VIH 2.0 V
Input Low Voltage VIL 0.8 V
Input Current IIN1 ±2 µA
Differential Driver Output (no load) VOD1 5 V
2V
Differential Driver Output
(with load) VOD2 1.5 5
1.0
-0.8
mA
0.25 mA
-0.2
Receiver Differential Threshold
Voltage -0.2 0.2 V
Receiver Input Hysteresis ΔVTH 70 mV
Receiver Output High Voltage VOH 3.5
Receiver Output Low Voltage VOL 0.4
V
Three-State (high impedance)
Output Current at Receiver IOZR ±1 µA
12 kΩ
CONDITIONS
DE = 0V;
VCC = 0V or 5.25V,
all devices except
MAX487E/MAX1487E
R = 27Ωor 50Ω, Figure 8
R = 27Ωor 50Ω, Figure 8
R = 27Ωor 50Ω, Figure 8
DE, DI, –
R
—
E
–
MAX487E/MAX1487E,
DE = 0V, VCC = 0V or 5.25V
DE, DI, –
R
—
E
–
DE, DI, –
R
—
E
–
-7V ≤VCM ≤12V
VCM = 0V
IO= -4mA, VID = 200mV
IO= 4mA, VID = -200mV
R = 50Ω(RS-422)
0.4V ≤VO≤2.4V
R = 27Ω(RS-485), Figure 8
-7V ≤VCM ≤12V, all devices except
MAX487E/MAX1487E
Receiver Input Resistance RIN
-7V ≤VCM ≤12V, MAX487E/MAX1487E 48 kΩ
VTH
IIN2
Input Current
(A, B)
VIN = 12V
VIN = -7V
VIN = 12V
VIN = -7V
V
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
2
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E
(VCC = 5V ±5%, TA= TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 5V ±5%, TA= TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
mA
7950V ≤VO≤VCC
IOSR
Receiver Short-Circuit Current
mA35 250-7V ≤VO≤12V (Note 4)IOSD2
Driver Short-Circuit Current,
VO= Low
mA35 250-7V ≤VO≤12V (Note 4)IOSD1
Driver Short-Circuit Current,
VO= High
MAX1487E,
–
R
—
E
–= 0V or VCC
250 400
350 650
CONDITIONS UNITSMIN TYP MAXSYMBOLPARAMETER
230 400
300 500
MAX481E/MAX485E,
–
R
—
E
–= 0V or VCC
500 900
MAX490E/MAX491E,
DE, DI, –
R
—
E
–= 0V or VCC 300 500
MAX488E/MAX489E,
DE, DI, –
R
—
E
–= 0V or VCC 120 250
DE = VCC
300 500DE = 0V
DE = VCC
DE = 0V
µAMAX481E/483E/487E, DE = 0V, –
R
—
E
–= VCC 0.5 10ISHDN
Supply Current in Shutdown
120 250
ICC
No-Load Supply Current
(Note 3)
DE = VCC
DE = 0V
MAX483E
MAX487E
MAX483E/MAX487E,
–
R
—
E
–= 0V or VCC
µA
52025MAX490EC/E, MAX491EC/E
MAX481E, MAX485E, MAX1487E
Driver Rise or Fall Time tR, tF
32040
Figures 10 and 12,
RDIFF = 54Ω,
CL1 = CL2 = 100pF
MAX490EC/E, MAX491EC/E
Figures 11 and 13, CL= 15pF, S2 closed
Figures 11 and 13, CL= 15pF, S1 closed
Figures 11 and 13, CL= 100pF, S1 closed
Figures 11 and 13, CL= 100pF, S2 closed
PARAMETER SYMBOL MIN TYP MAX UNITS
Driver Enable to Output High tZH 45 70
Receiver Input to Output tPLH, tPHL
Driver Output Skew to Output
ns
Driver Enable to Output Low tZL 45 70 ns
Driver Disable Time from Low tLZ 45 70
ns
|tPLH - tPHL |Differential
Receiver Skew
Driver Disable Time from High
tSKD
tHZ 45 70
5 ns
20 60 200
Receiver Enable to Output Low tZL 20 50
nsReceiver Enable to Output High
Driver Input to Output
tZH 20 50
nsReceiver Disable Time from Low tLZ 20 50
tPLH 10 40 60
nsReceiver Disable Time from High tHZ 20 50
MbpsMaximum Data Rate fMAX 2.5
ns
Time to Shutdown tSHDN 50 200 600
tSKEW 510
ns
CONDITIONS
Figures 10 and 14,
RDIFF = 54Ω,
CL1 = CL2 = 100pF
Figures 10 and 14, RDIFF = 54Ω,
CL1 = CL2 = 100pF
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
MAX481E (Note 5)
Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF
MAX481E, MAX485E, MAX1487E
ns
Figures 10 and 12, RDIFF = 54Ω, CL1 = CL2 = 100pF
tPHL 10 40 60
ns
ns
ns
20 60 150
ns
kV±15A, B, Y and Z pins, tested using Human Body ModelESD Protection
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
SWITCHING CHARACTERISTICS—MAX483E, MAX487E/MAX488E/MAX489E
(VCC = 5V ±5%, TA= TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E
(continued)
(VCC = 5V ±5%, TA= TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
225 1000
Figures 11 and 13, CL= 100pF, S2 closed
Figures 11 and 13, CL= 100pF, S1 closed
Figures 9 and 15, CL= 15pF, S2 closed,
A - B = 2V
CONDITIONS
ns45 100tZH(SHDN)
Driver Enable from Shutdown to
Output High (MAX481E)
ns
Figures 9 and 15, CL= 15pF, S1 closed,
B - A = 2V
tZL(SHDN)
Receiver Enable from Shutdown
to Output Low (MAX481E)
ns45 100tZL(SHDN)
Driver Enable from Shutdown to
Output Low (MAX481E)
ns225 1000tZH(SHDN)
Receiver Enable from Shutdown
to Output High (MAX481E)
UNITSMIN TYP MAXSYMBOLPARAMETER
tPLH
tSKEW Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF
tPHL
Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF
Driver Input to Output
Driver Output Skew to Output ns20 800
ns
ns2000
MAX483E/MAX487E, Figures 11 and 13,
CL= 100pF, S2 closed
tZH(SHDN)
Driver Enable from Shutdown to
Output High
250 2000
ns2500
MAX483E/MAX487E, Figures 9 and 15,
CL= 15pF, S1 closed
tZL(SHDN)
Receiver Enable from Shutdown
to Output Low
ns2500
MAX483E/MAX487E, Figures 9 and 15,
CL= 15pF, S2 closed
tZH(SHDN)
Receiver Enable from Shutdown
to Output High
ns2000
MAX483E/MAX487E, Figures 11 and 13,
CL= 100pF, S1 closed
tZL(SHDN)
Driver Enable from Shutdown to
Output Low
ns50 200 600MAX483E/MAX487E (Note 5) tSHDN
Time to Shutdown
tPHL
tPLH, tPHL < 50% of data period
Figures 9 and 15, CRL = 15pF, S2 closed
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 11 and 13, CL= 15pF, S2 closed
Figures 10 and 14, RDIFF = 54Ω,
CL1 = CL2 = 100pF
Figures 11 and 13, CL= 15pF, S1 closed
Figures 11 and 13, CL= 100pF, S1 closed
Figures 11 and 13, CL= 100pF, S2 closed
CONDITIONS
kbps250fMAX
250 800 2000
Maximum Data Rate
ns25 50tHZ
Receiver Disable Time from High
ns
250 800 2000
25 50tLZ
Receiver Disable Time from Low
ns25 50tZH
Receiver Enable to Output High
ns25 50tZL
Receiver Enable to Output Low
ns
ns
100
300 3000tHZ
tSKD
Driver Disable Time from High
ItPLH - tPHL IDifferential
Receiver Skew
Figures 10 and 14, RDIFF = 54Ω,
CL1 = CL2 = 100pF
ns300 3000tLZ
Driver Disable Time from Low
ns250 2000tZL
Driver Enable to Output Low
ns
Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF ns250 2000tR, tF
250 2000
Driver Rise or Fall Time
ns
tPLH
Receiver Input to Output
250 2000tZH
Driver Enable to Output High
UNITSMIN TYP MAXSYMBOLPARAMETER
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
4
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
0
5
10
15
20
25
30
35
40
45
50
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
MAX481E-01
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
1.5 2.0 2.51.00.50
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
-60 -20 60
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
MAX481E-04
TEMPERATURE (°C)
OUTPUT LOW VOLTAGE (V)
20 100-40 40080
IRO = 8mA
0
-5
-10
-15
-20
-25
1.5 3.0
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
MAX481E-02
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
5.04.54.02.0 2.5 3.5
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
4.8
-60 -20 60
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
MAX481E-03
TEMPERATURE (°C)
OUTPUT HIGH VOLTAGE (V)
20 100-40 40080
IRO = 8mA
0
10
20
30
40
50
60
70
80
90
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
MAX481E-05
DIFFERENTIAL OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
1.5 2.0 2.5 3.0 3.5 4.0 4.51.00.50
__________________________________________Typical Operating Characteristics
(VCC = 5V, TA= +25°C, unless otherwise noted.)
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 –
R
—
E
–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.
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
Maxim Integrated
±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.)
1.5
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
-60 -20 60
DRIVER DIFFERENTIAL OUTPUT
VOLTAGE vs. TEMPERATURE
MAX481E-06
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
20 100-40 40080
R = 54Ω
0
20
40
60
80
100
120
140
OUTPUT CURRENT vs.
DRIVER OUTPUT LOW VOLTAGE
MAX481E-07
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
024681012
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-8 -2
OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
MAX481E-08
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
642-6 -4 0
0
100
200
300
400
500
600
-60 -20 60
MAX481E/MAX485E/MAX490E/MAX491E
SUPPLY CURRENT vs. TEMPERATURE
MAX481E-09
TEMPERATURE (°C)
SUPPLY CURRENT (μA)
20 100-40 40080
MAX481E/MAX485E; DE = VCC, RE = X
MAX485E; DE = 0, RE = X,
MAX481E; DE = RE = 0
MAX490E/MAX491E; DE = RE = X
MAX481E; DE = 0, RE = VCC
0
100
200
300
400
500
600
-60 -20 60
MAX483E/MAX487E–MAX489E
SUPPLY CURRENT vs. TEMPERATURE
MAX481E-10
TEMPERATURE (°C)
SUPPLY CURRENT (μA)
20 100-40 40080
MAX483E; DE = VCC, RE = X
MAX487E; DE = VCC, RE = X
MAX483E/MAX487E; DE = 0, RE = VCC
MAX483E/MAX487E; DE = RE = 0,
MAX488E/MAX489E; DE = RE = X
0
100
200
300
400
500
600
-60 -20 60
MAX1487E
SUPPLY CURRENT vs. TEMPERATURE
MAX481E-11
TEMPERATURE (°C)
SUPPLY CURRENT (μA)
20 100-40 40080
MAX1487E; DE = VCC, RE = X
MAX1487E; DE = 0V, RE = X
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
6
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
______________________________________________________________Pin Description
1 2 Receiver Output: If A > B by 200mV, RO will be high;
If A < B by 200mV, RO will be low.
2 — Receiver Output Enable. RO is enabled when –
R
—
E
–is
low; RO is high impedance when –
R
—
E
–is high.
3 —
Driver Output Enable. The driver outputs, Y and Z, are
enabled by bringing DE high. They are high imped-
ance 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
Driver Input. A low on DI forces output Y low and out-
put Z high. Similarly, a high on DI forces output Y high
and output Z low.
6 — Noninverting Receiver Input and Noninverting Driver
Output
— 6 Inverting Driver Output
— 5 Noninverting Driver Output
5 4 Ground
— — No Connect—not internally connected
8 1 Positive Supply: 4.75V ≤VCC ≤5.25V
— 7 Inverting Receiver Input
7 — Inverting Receiver Input and Inverting Driver Output
— 8 Noninverting Receiver Input
PIN
2
3
4
5
—
10
9
6, 7
1, 8, 13
14
11
—
12
RO
–
R
—
E
–
DE
DI
A
Z
Y
GND
N.C.
VCC
B
B
A
FUNCTION
MAX489E
MAX491E
NAME
MAX488E
MAX490E
MAX481E/MAX483E
MAX485E/MAX487E
MAX1487E
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
MAX488E
MAX490E
TOP VIEW
1
2
3
4
RO
DI
GND
8
7
6
5
A
B
Z
Y
VCC
DIP/SO
R
D
Rt
Rt
VCC
5
6
7
8
RO
DI
GND
4GND
DI
RO
3
2
A
B
Y
Z
VCC
DR
RD
1
0.1μF
NOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.
MAX489E
MAX491E
DIP/SO
TOP VIEW
Rt
Rt
DE VCC
RE
GND
VCC RE
GND DE
RO
DI
9
10
12
11
B
A
Z
Y
0.1μF
5
RO
NC
DI
2
1, 8, 13
3 6, 7
144
1
2
3
4
5
6
7
14
13
12
11
10
9
8
VCC
N.C.
N.C.
A
B
Z
Y
N.C.
RO
RE
DE
DI
GND
GND
R
D
D
RD
R
Figure 2. MAX488E/MAX490E Pin Configuration and Typical Operating Circuit
Figure 3. MAX489E/MAX491E Pin Configuration and Typical Operating Circuit
MAX481E
MAX483E
MAX485E
MAX487E
MAX1487E
TOP VIEW
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.
1
2
3
4
8
5
VCC
0.1μF
GND
DI
DE
RE
RO R
D
Rt
Rt
7
6
D
R
DE
RE
DI
RO
A
B
1
2
3
4
8
7
6
5
VCC
B
A
GND
DI
DE
RE
RO
DIP/SO
R
D
B
A
Figure 1. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Pin Configuration and Typical Operating Circuit
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
8
Maxim Integrated
±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 OUTPUT
RE DE A-B RO
0
0
0
1
0
0
0
0
> +0.2V
< -0.2V
Inputs open
X
1
0
1
High-Z*
X = Don't care
High-Z = High impedance
* Shutdown mode for MAX481E/MAX483E/MAX487E
INPUTS OUTPUTS
RE DE DI Z Y
X
X
0
1
1
1
0
0
1
0
X
X
0
1
High-Z
High-Z*
1
0
High-Z
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 envi-
ronments where high-speed communication is important.
These devices eliminate the need for transient suppres-
sor 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, driver-
enable (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 electro-
static discharges encountered during handling and
assembly. The driver outputs and receiver inputs have
extra protection against static electricity. Maxim’s engi-
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 con-
tact discharge and IEC1000-4-2 air-gap discharge (for-
merly 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 dis-
charged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of inter-
est, which is then discharged into the test device
through a 1.5kΩresistor.
IEC1000-4-2
The IEC1000-4-2 standard covers ESD testing and per-
formance of finished equipment; it does not specifically
refer to integrated circuits (Figure 6).
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
CHARGE CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
150pF
RC 50M to 100M RD 330Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 6. IEC1000-4-2 ESD Test Model
tr = 0.7ns to 1ns
30ns
60ns
t
100%
90%
10%
IPEAK
I
R
R
Y
Z
VOD
VOC
Figure 8. Driver DC Test Load
Figure 7. IEC1000-4-2 ESD Generator Current Waveform
RECEIVER
OUTPUT
TEST POINT
1k
1k
S1
S2
VCC
CRL
15pF
Figure 9. Receiver Timing Test Load
CHARGE CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
100pF
RC 1M RD 1500Ω
HIGH
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 4. Human Body ESD Test Model
IP 100%
90%
36.8%
tRL TIME
tDL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Ir
10%
0
0
AMPERES
Figure 5. Human Body Model Current Waveform
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
10
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
DI
DE
3V
Y
Z
CL1
CL2
A
B
RO
RE
RDIFF
VID OUTPUT
UNDER TEST
500ΩS1
S2
VCC
CL
Figure 10. Driver/Receiver Timing Test Circuit Figure 11. Driver Timing Test Load
DI
3V
0V
Z
Y
VO
0V
-VO
VO
1.5V
tPLH
1/2 VO
10%
tR
90% 90%
tPHL
1.5V
1/2 VO
10%
tF
VDIFF = V (Y) - V (Z)
VDIFF
tSKEW = | tPLH - tPHL |
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0V
Y, Z
VOL
Y, Z
0V
1.5V 1.5V
VOL +0.5V
VOH -0.5V
2.3V
2.3V
tZL(SHDN), tZL tLZ
tZH(SHDN), tZH tHZ
DE
Figure 12. Driver Propagation Delays Figure 13. Driver Enable and Disable Times (except MAX488E
and MAX490E)
VOH
VOL
VID
-VID
1.5V
0V
1.5V
OUTPUT
INPUT 0V
RO
A-B
tPLH
tPHL OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0V
VCC
RO
RO
0V
1.5V 1.5V
VOL + 0.5V
VOH - 0.5V
1.5V
1.5V
tZL(SHDN), tZL tLZ
tZH(SHDN), tZH tHZ
RE
Figure 14. Receiver Propagation Delays Figure 15. Receiver Enable and Disable Times (except MAX488E
and MAX490E)
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
Maxim Integrated
11
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
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 with-
stand 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 resis-
tance. Its objective is to emulate the stress caused by
contact that occurs with handling and assembly during
manufacturing. Of course, all pins require this protec-
tion 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 (12kΩinput
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 12kΩreceiver input impedance.
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 analy-
sis of a 150kHz signal transmitted by a MAX481E,
MAX485E, MAX490E, MAX491E, or MAX1487E. High-
frequency harmonics with large amplitudes are evident.
Figure 17 shows the same information displayed for a
MAX483E, MAX487E, MAX488E, or MAX489E transmit-
ting under the same conditions. Figure 17’s high-fre-
quency 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 tZH
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
tZH(SHDN) and tZL(SHDN) enable times assume the
parts were shut down (see
Electrical Characteristics
).
500kHz/div
0Hz 5MHz
10dB/div
Figure 16. Driver Output Waveform and FFT Plot of
MAX485E/MAX490E/MAX491E/MAX1487E Transmitting a
150kHz Signal
500kHz/div
0Hz 5MHz
10dB/div
Figure 17. Driver Output Waveform and FFT Plot of
MAX483E/MAX487E–MAX489E Transmitting a 150kHz Signal
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
12
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
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 shut-
down circuit forces the driver outputs into a high-imped-
ance state if the die temperature rises excessively.
Propagation Delay
Many digital encoding schemes depend on the differ-
ence between the driver and receiver propagation
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
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 net-
work 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 possi-
ble. 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 differen-
tial voltage for the parts driving 4000 feet of 26AWG
twisted-pair wire at 110kHz into 100Ωloads.
100pF
100pF
R = 54ΩA
B
Y
D
Z
RRECEIVER
OUT
TTL IN
tR, tF < 6ns
Figure 18. Receiver Propagation Delay Test Circuit
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
Maxim Integrated
13
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
25ns/div
5V/div
RO
B
A
500mV/div
Figure 19. MAX481E/MAX485E/MAX490E/MAX1487E Receiver
t
PHL
25ns/div
5V/div
RO
B
A
500mV/div
Figure 20. MAX481E/MAX485E/MAX490E/MAX491E/
MAX1487E Receiver t
PLH
200ns/div
5V/div
RO
B
A
500mV/div
Figure 21. MAX483E/MAX487E–MAX489E Receiver t
PHL
200ns/div
5V/div
RO
B
A
500mV/div
Figure 22. MAX483E/MAX487E–MAX489E Receiver t
PLH
2μs/div
DO 0V
0V
5V
5V
-1V
0
DI
VA - VB
Figure 23. MAX481E/MAX485E/MAX490E/MAX491E/
MAX1487E System Differential Voltage at 110kHz Driving
4000ft of Cable
2μs/div
DO
0V
0V
5V
5V
-1V
1V
0
DI
VB - VA
Figure 24. MAX483E/MAX1487E–MAX489E System Differential
Voltage at 110kHz Driving 4000ft of Cable
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
14
Maxim Integrated
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
Figure 26. MAX488E–MAX491E Full-Duplex RS-485 Network
120Ω120Ω
R
D
RO
RE
DE
DI
A
B
Y
120Ω120Ω
DI
DI DIRO RO
RO
DE DE
DE
RE
RE
RE
Z
Z
Z
Z
YY
Y
AA
A
BB
B
DD
D
RR
R
MAX488E
MAX489E
MAX490E
MAX491E
NOTE: RE AND DE ON MAX489E/MAX491E ONLY.
DI RO DE
RE
A
B
RE
RERE
RO
RO
RO
DI
DI
DI
DE
DE
DE
DD
D
R
R
R
BB
B
A
A
A
120Ω120Ω
D
R
MAX481E
MAX483E
MAX485E
MAX487E
MAX1487E
Figure 25. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Typical Half-Duplex RS-485 Network
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
Maxim Integrated
15
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
Package Information
For the latest package outline information, go to
www.maxim-ic.com/packages.
Ordering Information (continued)
PART TEMP RANGE PIN-PACKAGE
MAX485ECPA 0°C to +70°C 8 Plastic DIP
MAX485ECSA 0°C to +70°C 8 SO
MAX485EEPA -40°C to +85°C 8 Plastic DIP
MAX485EESA -40°C to +85°C 8 SO
MAX487ECPA 0°C to +70°C 8 Plastic DIP
MAX487ECSA 0°C to +70°C 8 SO
MAX487EEPA -40°C to +85°C 8 Plastic DIP
MAX487EESA -40°C to +85°C 8 SO
MAX488ECPA 0°C to +70°C 8 Plastic DIP
MAX488ECSA 0°C to +70°C 8 SO
MAX488EEPA -40°C to +85°C 8 Plastic DIP
MAX488EESA -40°C to +85°C 8 SO
MAX489ECPD 0°C to +70°C 14 Plastic DIP
MAX489ECSD 0°C to +70°C 14 SO
PART TEMP RANGE PIN-PACKAGE
MAX489EEPD -40°C to +85°C 14 Plastic DIP
MAX489EESD -40°C to +85°C 14 SO
MAX490ECPA 0°C to +70°C 8 Plastic DIP
MAX490ECSA 0°C to +70°C 8 SO
MAX490EEPA -40°C to +85°C 8 Plastic DIP
MAX490EESA -40°C to +85°C 8 SO
MAX491ECPD 0°C to +70°C 14 Plastic DIP
MAX491ECSD 0°C to +70°C 14 SO
MAX491EEPD -40°C to +85°C 14 Plastic DIP
MAX491EESD -40°C to +85°C 14 SO
MAX1487ECPA 0°C to +70°C 8 Plastic DIP
MAX1487ECSA 0°C to +70°C 8 SO
MAX1487EEPA -40°C to +85°C 8 Plastic DIP
MAX1487EESA -40°C to +85°C 8 SO
PART NUMBER HALF/FULL
DUPLEX
DATA
RATE
(Mbps)
SLEW-
RATE
LIMITED
LOW-POWER
SHUTDOWN
RECEIVER/
DRIVER
ENABLE
QUIESCENT
CURRENT
(μA)
NUMBER OF
TRANSMITTERS
ON BUS
PIN
COUNT
MAX481E Half 2.5 No Yes Yes 300 32 8
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
Selector Guide
Chip Information
TRANSISTOR COUNT: 295
MAX481E/MAX483E/MAX485E/
MAX487E–MAX491E/MAX1487E
16 Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
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.
© 2003 Maxim Integrated The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.