Maxim MAX481EESA ±15kv esd-protected, slew-rate-limited, low-power, rs-485/rs-422 transceiver Datasheet

19-0410; Rev 3; 7/96
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
____________________________Features
♦ ESD Protection: ±15kV—Human Body Model
♦ Slew-Rate Limited for Error-Free Data
Transmission (MAX483E/487E/488E/489E)
♦ Low Quiescent Current:
120µA (MAX483E/487E/488E/489E)
230µA (MAX1487E)
300µA (MAX481E/485E/490E/491E)
♦ -7V to +12V Common-Mode Input Voltage Range
♦ Three-State Outputs
♦ 30ns Propagation Delays, 5ns Skew
(MAX481E/485E/490E/491E/1487E)
♦ Full-Duplex and Half-Duplex Versions Available
♦ Allows up to 128 Transceivers on the Bus
(MAX487E/MAX1487E)
♦ Current Limiting and Thermal Shutdown for
Driver Overload Protection
______________Ordering Information
________________________Applications
Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
PART
TEMP. RANGE
MAX481ECPA
0°C to +70°C
MAX481ECSA
0°C to +70°C
MAX481EEPA
MAX481EESA
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
Ordering Information continued on last page.
______________________________________________________________Selection Table
SLEW-RATE
LIMITED
LOW-POWER
SHUTDOWN
RECEIVER/
DRIVER
ENABLE
QUIESCENT
CURRENT
(µA)
NUMBER OF
TRANSMITTERS
ON BUS
PIN
COUNT
2.5
No
Yes
Yes
300
32
8
0.25
Yes
Yes
Yes
120
32
8
2.5
No
No
Yes
300
32
8
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
HALF/FULL
DUPLEX
MAX481E
Half
MAX483E
Half
MAX485E
Half
MAX487E
DATA RATE
(Mbps)
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E
_______________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 electrostatic discharge (ESD) shocks, without latchup. These parts
contain one driver and one receiver. The MAX483E,
MAX487E, MAX488E, and MAX489E feature reduced slewrate 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 Selection Table ). 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 fullduplex communications, while the MAX481E, MAX483E,
MAX485E, MAX487E, and MAX1487E are designed for halfduplex applications. For applications that are not ESD sensitive see the pin- and function-compatible MAX481,
MAX483, MAX485, MAX487–MAX491, and MAX1487.
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)
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
VOD2
CONDITIONS
MIN
R = 50Ω (RS-422)
TYP
MAX
UNITS
5
V
2
R = 27Ω (RS-485), Figure 8
1.5
5
∆VOD
R = 27Ω or 50Ω, Figure 8
0.2
V
VOC
R = 27Ω or 50Ω, Figure 8
3
V
∆VOD
R = 27Ω or 50Ω, Figure 8
0.2
V
Input High Voltage
VIH
Input Low Voltage
VIL
Input Current
IIN1
–—–
DE, DI, RE
–—–
DE, DI, RE
–—–
DE, DI, RE
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
VTH
2.0
V
0.8
V
±2
µA
mA
-7V ≤ VCM ≤ 12V
-0.2
0.2
mA
V
Receiver Input Hysteresis
∆VTH
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
70
mV
3.5
V
-7V ≤ VCM ≤ 12V, all devices except
MAX487E/MAX1487E
12
kΩ
-7V ≤ VCM ≤ 12V, MAX487E/MAX1487E
48
kΩ
RIN
_______________________________________________________________________________________
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
(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
MAX481E/MAX485E,
–—–
RE = 0V or VCC
DE = VCC
500
900
DE = 0V
300
500
MAX1487E,
–—–
RE = 0V or VCC
DE = VCC
300
500
MAX483E/MAX487E,
–—–
RE = 0V or VCC
DE = 0V
DE = VCC
UNITS
µA
230
400
MAX483E
350
650
MAX487E
250
120
0.5
400
250
10
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
Driver Output Skew to Output
Driver Rise or Fall Time
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
tPLH
tPHL
Figures 10 and 12, RDIFF = 54Ω,
CL1 = CL2 = 100pF
tSKEW
Figures 10 and 12, RDIFF = 54Ω, CL1 = CL2 = 100pF
tR, tF
Figures 10 and 12, MAX481E, MAX485E, MAX1487E
RDIFF = 54Ω,
CL1 = CL2 = 100pF MAX490EC/E, MAX491EC/E
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
DC ELECTRICAL CHARACTERISTICS (continued)
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
TYP
MAX
UNITS
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
Driver Enable from Shutdown to
tZH(SHDN)
Output High (MAX481E)
CONDITIONS
MIN
SWITCHING CHARACTERISTICS—MAX483E, MAX487E/MAX488E/MAX489E
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
Driver Input to Output
SYMBOL
tPLH
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
Receiver Disable Time from High
tHZ
Figures 9 and 15, CRL = 15pF, S2 closed
25
50
Maximum Data Rate
Time to Shutdown
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
fMAX
tPLH, tPHL < 50% of data period
250
tSHDN
MAX483E/MAX487E (Note 5)
50
tZH(SHDN)
tZL(SHDN)
tZH(SHDN)
tZL(SHDN)
ns
kbps
200
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
_______________________________________________________________________________________
600
ns
2000
ns
2000
ns
2500
ns
2500
ns
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
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
-5
IRO = 8mA
4.4
4.2
4.0
3.8
3.6
3.4
3.2
5
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
0.8
IRO = 8mA
-60 -40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
90
80
OUTPUT CURRENT (mA)
0.7
0.6
0.5
0.4
0.3
70
60
50
40
30
0.2
20
0.1
10
0
MAX481E-05
0.9
5.0
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
MAX481E-04
0
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
-25
MAX481E-01
50
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
MAX481E-03
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
0
-60 -40 -20
0
20
40
60
TEMPERATURE (°C)
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
NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICS
____________________________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
100
80
60
40
-80
-70
-60
-50
-40
-30
-20
1.6
20
1.5
0
-60 -40 -20
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
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
SUPPLY CURRENT (µA)
MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
80 100
-60 -40 -20
0
20
40
60
TEMPERATURE (°C)
80 100
-60 -40 -20
0
20
40
60
TEMPERATURE (°C)
_______________________________________________________________________________________
80 100
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
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
Ground
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
_______________________________________________________________________________________
7
MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E
______________________________________________________________Pin Description
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
VCC 1
R
RO 2
DI 3
GND 4
D
8
A
7
B
6
Z
5
Y
DI
3
Rt
D
R
6 Z
RO
8 A
RO
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
R
2
RE
3
12 A
DE
4
11 B
DI
5
10 Z
6
GND
7
13 N.C.
D
9
Y
8
N.C.
9
DI
5
MAX489E
MAX491E
Y
Rt
D
Z
12
RO
2
R
A
Rt
D
11
B
NC
1, 8, 13
6, 7 GND
RE
GND
Figure 3. MAX489E/MAX491E Pin Configuration and Typical Operating Circuit
8
RO
R
10
3
DIP/SO
VCC RE
0.1µF
14
14 V CC
RO
GND
VCC
_______________________________________________________________________________________
DE
DI
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
Table 1. Transmitting
Table 2. Receiving
INPUTS
RE
DE
OUTPUTS
DI
Z
INPUTS
OUTPUT
Y
RE
DE
A-B
RO
0
> +0.2V
1
X
1
1
0
1
0
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-
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
__________Function Tables (MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E)
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%
R C 50M to 100M
CHARGE CURRENT
LIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
150pF
R D 330Ω
90%
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
I PEAK
MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
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
______________________________________________________________________________________
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
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
tPHL
tPLH
1.5V
1.5V
0V
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
tLZ
VCC
RO
1.5V OUTPUT NORMALLY LOW
RO
1.5V
0V
VOL + 0.5V
OUTPUT NORMALLY HIGH
VOH - 0.5V
0V
tZH(SHDN), tZH
Figure 14. Receiver Propagation Delays
tHZ
Figure 15. Receiver Enable and Disable Times (except MAX488E
and MAX490E)
______________________________________________________________________________________
11
MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E
3V
DE
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).
______________________________________________________________________________________
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
TTL IN
tR, tF < 6ns
B
D
R
R = 54Ω
Y
RECEIVER
OUT
A
100pF
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
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
100pF
Z
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.
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
VA - VB
0
VB - VA
-1V
-1V
5V
DO
2µs/div
Figure 23. MAX481E/MAX485E/MAX490E/MAX491E/
MAX1487E System Differential Voltage at 110kHz Driving
4000ft of Cable
14
DO
5V
0V
0V
2µs/div
Figure 24. MAX483E/MAX1487E–MAX489E System Differential
Voltage at 110kHz Driving 4000ft of Cable
______________________________________________________________________________________
±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers
DI
MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E
120Ω
120Ω
DE
B
B
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
Y
120Ω
R
RO
RE
120Ω
D
B
Z
Z
B
DE
DI
DI
DE
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
______________________________________________________________________________________
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
MAX483ECPA
0°C to +70°C
MAX483ECSA
0°C to +70°C
MAX483EEPA
MAX483EESA
MAX485ECPA
MAX485ECSA
MAX485EEPA
MAX485EESA
MAX487ECPA
MAX487ECSA
MAX487EEPA
MAX487EESA
MAX488ECPA
MAX488ECSA
MAX488EEPA
MAX488EESA
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
PART
MAX489ECPD
MAX489ECSD
MAX489EEPD
MAX489EESD
MAX490ECPA
MAX490ECSA
MAX490EEPA
MAX490EESA
MAX491ECPD
MAX491ECSD
MAX491EEPD
MAX491EESD
MAX1487ECPA
MAX1487ECSA
MAX1487EEPA
MAX1487EESA
TEMP. RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
14 Plastic DIP
14 SO
14 Plastic DIP
14 SO
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
14 Plastic DIP
14 SO
14 Plastic DIP
14 SO
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
___________________Chip Information
TRANSISTOR COUNT: 295
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.
16 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600
© 1996 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.