MAX488CUA+T [MAXIM]
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| 型号： | MAX488CUA+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
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19-0410; Rev 3; 7/96
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
35–9/MAX1487E
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
♦ ESD Protection: ±15kV—Human Body Model
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
c onta in one d rive r a nd one re c e ive r. 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.
♦ 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)
These transceivers draw as little as 120µA supply current
when unloaded or when fully loaded with disabled drivers
(s e e Se le c tion Ta b le ). Ad d itiona lly, 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.
♦ Full-Duplex and Half-Duplex Versions Available
♦ Allows up to 128 Transceivers on the Bus
(MAX487E/MAX1487E)
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 guaran-
tees a logic-high output if the input is open circuit.
♦ Current Limiting and Thermal Shutdown for
Driver Overload Protection
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 MAX481E, MAX483E,
MAX485E, MAX487E, and MAX1487E are designed for half-
duplex applications. For applications that are not ESD sen-
sitive se e the p in- a nd func tion-c ompa tible MAX481,
MAX483, MAX485, MAX487–MAX491, and MAX1487.
______________Ord e rin g In fo rm a t io n
PART
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
8 Plastic DIP
8 SO
MAX481ECPA
MAX481ECSA
MAX481EEPA
MAX481EESA
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
8 Plastic DIP
8 SO
________________________Ap p lic a t io n s
Low-Power RS-485 Transceivers
Ordering Information continued on last page.
Low-Power RS-422 Transceivers
Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
______________________________________________________________S e le c t io n Ta b le
RECEIVER/
DRIVER
ENABLE
QUIESCENT
CURRENT
(µA)
NUMBER OF
TRANSMITTERS
ON BUS
PART
NUMBER
HALF/FULL DATA RATE SLEW-RATE LOW-POWER
PIN
COUNT
DUPLEX
(Mbps)
LIMITED
SHUTDOWN
MAX481E
MAX483E
MAX485E
MAX487E
MAX488E
MAX489E
MAX490E
MAX491E
MAX1487E
Half
Half
Half
Half
Full
Full
Full
Full
Half
2.5
0.25
2.5
No
Yes
No
Yes
Yes
No
Yes
No
No
No
No
No
Yes
Yes
Yes
Yes
No
300
120
300
120
120
120
300
300
230
32
32
8
8
32
8
0.25
0.25
0.25
2.5
Yes
Yes
Yes
No
128
32
8
8
Yes
No
32
14
8
32
2.5
No
Yes
Yes
32
14
8
2.5
No
128
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V ).............................................................12V
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
CC
–—–
Control Input Voltage (RE, DE)...................-0.5V to (V + 0.5V)
CC
CC
Driver Input Voltage (DI).............................-0.5V to (V + 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 (V + 0.5V)
CC
Continuous Power Dissipation (T = +70°C)
A
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ....727mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(V = 5V ±5%, T = T
to T , unless otherwise noted.) (Notes 1, 2)
MAX
CC
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Differential Driver Output (no load)
V
OD1
5
V
R = 50Ω (RS-422)
2
Differential Driver Output
(with load)
V
OD2
V
R = 27Ω (RS-485), Figure 8
1.5
5
Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
∆V
R = 27Ω or 50Ω, Figure 8
0.2
V
V
V
OD
Driver Common-Mode Output
Voltage
V
OC
R = 27Ω or 50Ω, Figure 8
R = 27Ω or 50Ω, Figure 8
3
Change in Magnitude of Driver
Common-Mode Output Voltage
for Complementary Output States
∆V
OD
0.2
–—–
Input High Voltage
Input Low Voltage
Input Current
V
IH
DE, DI, RE
2.0
V
V
–—–
V
IL
DE, DI, RE
0.8
±2
–—–
I
IN1
DE, DI, RE
µA
DE = 0V;
V
= 12V
= -7V
1.0
IN
V
CC
= 0V or 5.25V,
mA
all devices except
MAX487E/MAX1487E
Input Current
(A, B)
V
IN
-0.8
I
IN2
V
= 12V
= -7V
0.25
-0.2
IN
MAX487E/MAX1487E,
mA
V
DE = 0V, V = 0V or 5.25V
CC
V
IN
Receiver Differential Threshold
Voltage
V
TH
-7V ≤ V ≤ 12V
-0.2
3.5
0.2
CM
Receiver Input Hysteresis
∆V
TH
V
CM
= 0V
70
mV
V
Receiver Output High Voltage
Receiver Output Low Voltage
V
I = -4mA, V = 200mV
O ID
OH
V
OL
I
= 4mA, V = -200mV
0.4
±1
V
O
ID
Three-State (high impedance)
Output Current at Receiver
I
0.4V ≤ V ≤ 2.4V
µA
kΩ
kΩ
OZR
O
-7V ≤ V ≤ 12V, all devices except
MAX487E/MAX1487E
CM
12
48
Receiver Input Resistance
R
IN
-7V ≤ V ≤ 12V, MAX487E/MAX1487E
CM
35–9/MAX1487E
2
_______________________________________________________________________________________
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
35–9/MAX1487E
DC ELECTRICAL CHARACTERISTICS (continued)
(V = 5V ±5%, T = T
to T , unless otherwise noted.) (Notes 1, 2)
MAX
CC
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX488E/MAX489E,
120
250
–—–
DE, DI, RE = 0V or V
CC
MAX490E/MAX491E,
–—–
DE, DI, RE = 0V or V
300
500
CC
DE = V
500
300
300
230
350
250
120
0.5
900
500
500
400
650
400
250
10
CC
MAX481E/MAX485E,
–—–
No-Load Supply Current
(Note 3)
RE = 0V or V
CC
I
µA
CC
DE = 0V
DE = V
CC
MAX1487E,
–—–
RE = 0V or V
CC
DE = 0V
MAX483E
MAX487E
DE = V
MAX483E/MAX487E,
–—–
RE = 0V or V
CC
CC
DE = 0V
–—–
Supply Current in Shutdown
Driver Short-Circuit Current,
I
MAX481E/483E/487E, DE = 0V, RE = V
µA
SHDN
CC
I
-7V ≤ V ≤12V (Note 4)
35
250
mA
OSD1
O
V
O
= High
Driver Short-Circuit Current,
= Low
I
-7V ≤ V ≤12V (Note 4)
35
7
250
95
mA
OSD2
O
V
O
Receiver Short-Circuit Current
ESD Protection
I
0V ≤ V ≤ V
mA
kV
OSR
O
CC
A, B, Y and Z pins, tested using Human Body Model
±15
SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E
(V = 5V ±5%, T = T
to T , unless otherwise noted.) (Notes 1, 2)
MAX
CC
A
MIN
PARAMETER
SYMBOL
CONDITIONS
Figures 10 and 12, R = 54Ω,
MIN
10
TYP
40
40
5
MAX
60
UNITS
ns
t
PLH
PHL
DIFF
Driver Input to Output
C
= C = 100pF
L2
t
L1
10
60
Driver Output Skew to Output
Driver Rise or Fall Time
t
Figures 10 and 12, R
= 54Ω, C = C = 100pF
10
ns
SKEW
DIFF
L1
L2
Figures 10 and 12,
MAX481E, MAX485E, MAX1487E
MAX490EC/E, MAX491EC/E
3
5
20
20
40
25
t , t
R = 54Ω,
DIFF
ns
R
F
C
= C = 100pF
L1
L2
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
t
Figures 11 and 13, C = 100pF, S2 closed
45
45
45
45
70
70
70
70
ns
ns
ns
ns
ZH
L
t
Figures 11 and 13, C = 100pF, S1 closed
L
ZL
LZ
HZ
t
Figures 11 and 13, C = 15pF, S1 closed
L
t
Figures 11 and 13, C = 15pF, S2 closed
L
Figures 10 and 14,
MAX481E, MAX485E, MAX1487E
MAX490EC/E, MAX491EC/E
20
20
60
60
200
150
Receiver Input to Output
t
, t
R = 54Ω,
DIFF
ns
PLH PHL
C
= C = 100pF
L1
L2
Figures 10 and 14, R
= 54Ω,
| t
- tPHL | Differential
DIFF
PLH
t
5
ns
SKD
C
= C = 100pF
L2
L1
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
t
Figures 9 and 15, C = 15pF, S1 closed
20
20
20
20
50
50
50
50
ns
ns
ZL
RL
t
Figures 9 and 15, C = 15pF, S2 closed
RL
ZH
t
LZ
Figures 9 and 15, C = 15pF, S1 closed
ns
RL
t
Figures 9 and 15, C = 15pF, S2 closed
RL
ns
HZ
f
2.5
50
Mbps
ns
MAX
Time to Shutdown
t
MAX481E (Note 5)
200
600
SHDN
_______________________________________________________________________________________
3
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E
(continued)
(V = 5V ±5%, T = T
to T , unless otherwise noted.) (Notes 1, 2)
MAX
CC
A
MIN
PARAMETER
SYMBOL
CONDITIONS
Figures 11 and 13, C = 100pF, S2 closed
MIN
TYP
MAX
UNITS
Driver Enable from Shutdown to
Output High (MAX481E)
t
t
t
t
45
100
ns
ZH(SHDN)
ZL(SHDN)
ZH(SHDN)
ZL(SHDN)
L
Driver Enable from Shutdown to
Output Low (MAX481E)
Figures 11 and 13, C = 100pF, S1 closed
45
100
1000
1000
ns
ns
ns
L
Receiver Enable from Shutdown
to Output High (MAX481E)
Figures 9 and 15, C = 15pF, S2 closed,
L
A - B = 2V
225
225
Receiver Enable from Shutdown
to Output Low (MAX481E)
Figures 9 and 15, C = 15pF, S1 closed,
L
B - A = 2V
SWITCHING CHARACTERISTICS—MAX483E, MAX487E/MAX488E/MAX489E
(V = 5V ±5%, T = T
to T , unless otherwise noted.) (Notes 1, 2)
MAX
CC
A
MIN
PARAMETER
Driver Input to Output
SYMBOL
CONDITIONS
MIN
250
250
TYP
800
800
MAX
2000
2000
UNITS
t
t
PLH
PHL
Figures 10 and 12, R
= 54Ω,
DIFF
DIFF
DIFF
ns
C
= C = 100pF
L2
L1
Figures 10 and 12, R
= C = 100pF
= 54Ω,
= 54Ω,
Driver Output Skew to Output
Driver Rise or Fall Time
t
20
800
ns
ns
SKEW
C
L1
L2
Figures 10 and 12, R
= C = 100pF
t , t
250
2000
R
F
C
L1
L2
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
t
Figures 11 and 13, C = 100pF, S2 closed
250
250
300
300
250
250
2000
2000
3000
3000
2000
2000
ns
ns
ns
ns
ZH
L
t
Figures 11 and 13, C = 100pF, S1 closed
L
ZL
LZ
HZ
t
Figures 11 and 13, C = 15pF, S1 closed
L
t
Figures 11 and 13, C = 15pF, S2 closed
L
t
t
PLH
PHL
Figures 10 and 14, R
= 54Ω,
DIFF
Receiver Input to Output
ns
ns
C
= C = 100pF
L2
L1
Figures 10 and 14, R
= C = 100pF
= 54Ω,
I t
- tPHL I Differential
DIFF
PLH
t
100
SKD
C
L1
L2
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
t
Figures 9 and 15, C = 15pF, S1 closed
25
25
25
25
50
50
50
50
ns
ns
ZL
RL
t
Figures 9 and 15, C = 15pF, S2 closed
RL
ZH
t
LZ
Figures 9 and 15, C = 15pF, S1 closed
ns
RL
t
Figures 9 and 15, C = 15pF, S2 closed
ns
HZ
RL
f
t
, t < 50% of data period
PLH PHL
250
50
kbps
ns
MAX
Time to Shutdown
t
MAX483E/MAX487E (Note 5)
200
600
SHDN
Driver Enable from Shutdown to
Output High
MAX483E/MAX487E, Figures 11 and 13,
t
t
2000
ns
ns
ns
ns
ZH(SHDN)
C
= 100pF, S2 closed
L
Driver Enable from Shutdown to
Output Low
MAX483E/MAX487E, Figures 11 and 13,
= 100pF, S1 closed
t
2000
2500
2500
ZL(SHDN)
ZH(SHDN)
C
L
Receiver Enable from Shutdown
to Output High
MAX483E/MAX487E, Figures 9 and 15,
= 15pF, S2 closed
C
L
Receiver Enable from Shutdown
to Output Low
MAX483E/MAX487E, Figures 9 and 15,
= 15pF, S1 closed
t
ZL(SHDN)
C
35–9/MAX1487E
L
4
_______________________________________________________________________________________
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
35–9/MAX1487E
NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICS
Note 1: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device
ground unless otherwise specified.
Note 2: All typical specifications are given for V = 5V and T = +25°C.
CC
A
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.
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(V = 5V, T = +25°C, unless otherwise noted.)
CC
A
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
50
-25
-20
-15
-10
4.8
4.6
4.4
4.2
4.0
3.8
3.6
45
40
35
I
RO
= 8mA
30
25
20
15
3.4
3.2
3.0
10
5
-5
0
0
0
0.5
1.0
1.5
2.0
2.5
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT HIGH VOLTAGE (V)
-60 -40 -20
0
20 40 60 80 100
OUTPUT LOW VOLTAGE (V)
TEMPERATURE (°C)
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
90
80
70
60
0.9
0.8
0.7
0.6
0.5
0.4
0.3
I
RO
= 8mA
50
40
30
0.2
0.1
0
20
10
0
-60 -40 -20
0
20 40 60 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)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
____________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(V = 5V, T = +25°C, unless otherwise noted.)
CC
A
OUTPUT CURRENT vs.
DRIVER OUTPUT LOW VOLTAGE
OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
DRIVER DIFFERENTIAL OUTPUT
VOLTAGE vs. TEMPERATURE
140
120
-100
-90
-80
-70
2.3
R = 54Ω
2.2
2.1
2.0
1.9
100
-60
-50
80
60
-40
-30
1.8
1.7
40
20
0
-20
-10
0
1.6
1.5
0
2
4
6
8
10
12
-8
-6
-4
-2
0
2
4
6
-60 -40 -20
0
20 40 60 80 100
OUTPUT LOW VOLTAGE (V)
OUTPUT HIGH VOLTAGE (V)
TEMPERATURE (°C)
MAX481E/MAX485E/MAX490E/MAX491E
SUPPLY CURRENT vs. TEMPERATURE
MAX1487E
SUPPLY CURRENT vs. TEMPERATURE
MAX483E/MAX487E–MAX489E
SUPPLY CURRENT vs. TEMPERATURE
600
500
400
300
200
600
500
400
300
200
600
500
400
300
200
MAX481E/MAX485E; DE = VCC, RE = X
MAX483E; DE = VCC, RE = X
MAX487E; DE = VCC, RE = X
MAX1487E; DE = VCC, RE = X
MAX1487E; DE = 0V, RE = X
MAX485E; DE = 0, RE = X,
MAX481E; DE = RE = 0
MAX490E/MAX491E; DE = RE = X
MAX483E/MAX487E; DE = RE = 0,
MAX488E/MAX489E; DE = RE = X
100
0
100
0
100
0
MAX481E; DE = 0, RE = V
CC
MAX483E/MAX487E; DE = 0, RE = V
CC
-60 -40 -20
0
20 40 60 80 100
-60 -40 -20
0
20 40 60 80 100
-60 -40 -20
0
20 40 60 80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
35–9/MAX1487E
6
_______________________________________________________________________________________
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
335–9/MAX1487E5–9/MAX1487E
______________________________________________________________P in De s c rip t io n
PIN
MAX481E/MAX483E
MAX485E/MAX487E
MAX1487E
NAME
FUNCTION
MAX488E
MAX490E
MAX489E
MAX491E
Receiver Output: If A > B by 200mV, RO will be high;
If A < B by 200mV, RO will be low.
1
2
2
2
3
RO
–—–
Receiver Output Enable. RO is enabled when RE is
–—–
–—–
RE
—
low; RO is high impedance when RE is high.
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,
3
4
—
4
DE
the parts function as line drivers. While they are high
–—–
impedance, they function as line receivers if RE is low.
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.
3
5
DI
5
4
5
6
6, 7
9
GND
Y
Ground
—
—
Noninverting Driver Output
Inverting Driver Output
10
Z
Noninverting Receiver Input and Noninverting Driver
Output
6
—
—
A
—
7
8
—
7
12
—
A
B
B
Noninverting Receiver Input
Inverting Receiver Input and Inverting Driver Output
Inverting Receiver Input
—
8
11
1
14
V
CC
Positive Supply: 4.75V ≤ V ≤ 5.25V
CC
—
—
1, 8, 13
N.C.
No Connect—not internally connected
_______________________________________________________________________________________
7
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
MAX481E
0.1µF
MAX483E
TOP VIEW
DE
MAX485E
MAX487E
MAX1487E
DI
R
R
1
2
3
4
RO
RE
DE
DI
1
2
3
4
RO
RE
DE
DI
8
8
7
6
5
V
CC
B
Rt
V
D
CC
B
A
7
B
Rt
6
A
A
RO
R
D
D
5
GND
GND
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
V
CC
V
CC
1
MAX488E
MAX490E
Y
Z
5
6
TOP VIEW
3
2
Rt
DI
RO
DI
D
R
V
1
2
3
4
R
8
7
6
5
A
B
Z
CC
RO
DI
8
7
A
B
Rt
RO
R
D
GND
Y
D
DIP/SO
4
GND
GND
NOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.
Figure 2. MAX488E/MAX490E Pin Configuration and Typical Operating Circuit
V
CC
DE
V
CC
RE
TOP VIEW
0.1µF
4
14
MAX489E
MAX491E
N.C.
1
2
3
4
5
6
7
14
V
CC
9
Y
R
RO
RE
13 N.C.
5
Rt
DI
RO
D
R
10
12
11
10
9
A
Z
DE
B
12
11
A
2
Rt
DI
Z
RO
NC
R
D
DI
D
GND
GND
Y
B
1, 8, 13
8
N.C.
3
6, 7
GND
DIP/SO
Figure 3. MAX489E/MAX491E Pin Configuration and Typical Operating Circuit
_______________________________________________________________________________________
RE
GND DE
35–9/MAX1487E
8
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
35–9/MAX1487E
__________Fu n c t io n Ta b le s (MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E)
Table 1. Transmitting
Table 2. Receiving
INPUTS
OUTPUTS
INPUTS
OUTPUT
RE
DE
A-B
RO
RE
DE
DI
Z
Y
0
0
> +0.2V
1
X
1
1
0
1
0
0
0
0
0
< -0.2V
Inputs open
X
0
1
X
0
1
0
0
0
1
0
X
X
High-Z
High-Z
1
High-Z
1
High-Z
High-Z
*
*
*
X = Don't care
X = Don't care
High-Z = High impedance
Shutdown mode for MAX481E/MAX483E/MAX487E
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
e ve nt, Ma xim’s MAX481E, MAX483E, MAX485E,
MAX487E–MAX491E, and MAX1487E keep working
without latchup.
__________Ap p lic a t io n s In fo rm a t io n
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.
ESD p rote c tion c a n b e te s te d in va rious wa ys ; 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).
The MAX481E, MAX485E, MAX490E, MAX491E, and
MAX1487E can transmit and receive at data rates up to
2.5Mbps, while the MAX483E, MAX487E, MAX488E,
a nd MAX489E a re s p e c ifie d for d a ta ra te s up to
250kb p s . The MAX488E–MAX491E a re full-d up le x
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.
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-
e s t, whic h is the n d is c ha rg e d into the te s t d e vic e
through a 1.5kΩ resistor.
±1 5 k V ES D P ro t e c t io n
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-
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).
_______________________________________________________________________________________
9
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
R
C
1M
R 1500Ω
D
I 100%
P
90%
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
r
DISCHARGE
RESISTANCE
CHARGE CURRENT
LIMIT RESISTOR
AMPERES
HIGH
VOLTAGE
DC
DEVICE
UNDER
TEST
C
STORAGE
CAPACITOR
s
36.8%
100pF
SOURCE
10%
0
TIME
0
t
RL
t
DL
CURRENT WAVEFORM
Figure 4. Human Body ESD Test Model
Figure 5. Human Body Model Current Waveform
I
100%
90%
R
C
50M to 100M
R 330Ω
D
DISCHARGE
RESISTANCE
CHARGE CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
STORAGE
CAPACITOR
s
150pF
SOURCE
10%
t
t
r
= 0.7ns to 1ns
30ns
60ns
Figure 6. IEC1000-4-2 ESD Test Model
Figure 7. IEC1000-4-2 ESD Generator Current Waveform
Y
1k
TEST POINT
R
RECEIVER
OUTPUT
V
CC
S1
S2
V
OD
C
RL
1k
15pF
R
V
OC
Z
Figure 8. Driver DC Test Load
Figure 9. Receiver Timing Test Load
35–9/MAX1487E
10 ______________________________________________________________________________________
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
35–9/MAX1487E
3V
DE
C
L1
A
B
V
CC
Y
Z
S1
S2
500Ω
R
RO
DIFF
DI
OUTPUT
UNDER TEST
V
ID
RE
C
L
C
L2
Figure 10. Driver/Receiver Timing Test Circuit
Figure 11. Driver Timing Test Load
3V
3V
DE
DI
1.5V
1.5V
1.5V
1.5V
0V
0V
t
t
PHL
PLH
1/2 V
O
t
LZ
t
, t
ZL(SHDN) ZL
Z
Y, Z
V
2.3V
V
+0.5V
O
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
OL
V
OL
Y
1/2 V
O
V
= V (Y) - V (Z)
DIFF
Y, Z
0V
V
O
V
OH
-0.5V
2.3V
V
DIFF
90%
90%
0V
-V
10%
10%
O
t
, t
t
HZ
ZH(SHDN) ZH
t
R
t
F
t
| t - t
|
SKEW = PLH PHL
Figure 12. Driver Propagation Delays
Figure 13. Driver Enable and Disable Times (except MAX488E
and MAX490E)
3V
RE
1.5V
1.5V
0V
V
OH
t
t
, t
RO
LZ
ZL(SHDN) ZL
1.5V
1.5V
0V
V
OL
OUTPUT
V
RO
CC
1.5V
V
+ 0.5V
- 0.5V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
OL
t
t
PLH
PHL
V
ID
A-B
0V
-V
INPUT
ID
RO
V
OH
1.5V
0V
t
, t
t
HZ
ZH(SHDN) ZH
Figure 14. Receiver Propagation Delays
Figure 15. Receiver Enable and Disable Times (except MAX488E
and MAX490E)
______________________________________________________________________________________ 11
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
10dB/div
10dB/div
0Hz
5MHz
0Hz
5MHz
500kHz/div
500kHz/div
Figure 16. Driver Output Waveform and FFT Plot of
Figure 17. Driver Output Waveform and FFT Plot of
MAX485E/MAX490E/MAX491E/MAX1487E Transmitting a
150kHz Signal
MAX483E/MAX487E–MAX489E 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 with-
stand voltage measured to IEC1000-4-2 is generally
lowe r tha n tha t me a s ure d us ing the Huma n Bod y
Model. Figure 7 shows the current waveform for the 8kV
IEC1000-4-2 ESD contact-discharge test.
MAX4 8 3 E/MAX4 8 7 E/MAX4 8 8 E/MAX4 8 9 E:
Re d u c e d EMI a n d Re fle c t io n s
The MAX483E and MAX487E–MAX489E are slew-rate
limite d , minimizing EMI a nd re d uc ing re fle c tions
caused by improperly terminated cables. Figure 16
shows the driver output waveform and its Fourier analy-
s is of a 150kHz s ig na l tra ns mitte d b y 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.
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 Ma c hine Mod e l for ESD te s ts a ll p ins us ing 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.
Lo w -P o w e r S h u t d o w n Mo d e
(MAX4 8 1 E/MAX4 8 3 E/MAX4 8 7 E)
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.
MAX4 8 7 E/MAX1 4 8 7 E:
1 2 8 Tra n s c e ive rs o n t h e Bu s
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.
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.
For the MAX481E, MAX483E, and MAX487E, the t
ZH
and t enable times assume the part was not in the
ZL
low-power shutdown state (the MAX485E, MAX488E–
MAX491E, and MAX1487E can not be shut down). The
t
a nd t
e na b le time s a s s ume the
ZH(SHDN)
ZL(SHDN)
35–9/MAX1487E
parts were shut down (see Electrical Characteristics).
12 ______________________________________________________________________________________
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
35–9/MAX1487E
delay times. Typical propagation delays are shown in
Figures 19–22 using Figure 18’s test circuit.
The difference in receiver delay times, t
- t
, is
PHL
PLH
typ ic a lly und e r 13ns for the MAX481E, MAX485E,
MAX490E, MAX491E, and MAX1487E, and is typically
le s s tha n 100ns for the MAX483E a nd MAX487E–
MAX489E.
100pF
Z
B
A
TTL IN
t , t < 6ns
RECEIVER
OUT
D
R
R
F
R = 54Ω
Y
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.
100pF
Typ ic a l Ap p lic a t io n s
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.
Figure 18. Receiver Propagation Delay Test Circuit
It takes the drivers and receivers longer to become
enabled from the low-power shutdown state (t ),
ZH(SHDN
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.
t
) than from the operating mode (t , t ). (The
ZL(SHDN)
ZH ZL
parts are in operating mode if the RE, DE inputs equal a
logical 0,1 or 1,1 or 0, 0.)
Drive r Ou t p u t P ro t e c t io n
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.
Bypass the V pin with 0.1µF.
CC
Is o la t e d RS -4 8 5
For isolated RS-485 applications, see the MAX253 and
MAX1480 data sheets.
Lin e Le n g t h vs . Da t a Ra t e
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 100Ω loads.
P ro p a g a t io n De la y
Many digital encoding schemes depend on the differ-
e nc e b e twe e n the d rive r a nd re c e ive r p rop a g a tion
______________________________________________________________________________________ 13
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
A
B
500mV/div
500mV/div
A
B
RO
5V/div
RO
5V/div
25ns/div
25ns/div
Figure 20. MAX481E/MAX485E/MAX490E/MAX491E/
Figure 19. MAX481E/MAX485E/MAX490E/MAX1487E Receiver
MAX1487E Receiver t
PLH
t
PHL
B
A
500mV/div
B
500mV/div
A
RO
5V/div
RO
5V/div
200ns/div
200ns/div
Figure 21. MAX483E/MAX487E–MAX489E Receiver t
Figure 22. MAX483E/MAX487E–MAX489E Receiver t
PHL
PLH
DI
5V
DI
5V
0V
0V
1V
0
0
V - V
V - V
B
A
A
B
-1V
-1V
DO
5V
0V
5V
0V
DO
2µs/div
2µs/div
Figure 23. MAX481E/MAX485E/MAX490E/MAX491E/
MAX1487E System Differential Voltage at 110kHz Driving
4000ft of Cable
Figure 24. MAX483E/MAX1487E–MAX489E System Differential
Voltage at 110kHz Driving 4000ft of Cable
35–9/MAX1487E
14 ______________________________________________________________________________________
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
35–9/MAX1487E
120Ω
120Ω
DE
DI
B
A
B
A
DI
D
D
DE
B
A
B
A
RO
RE
RO
RE
R
R
R
R
D
D
MAX481E
MAX483E
MAX485E
MAX487E
MAX1487E
DI
DE RO RE
DI
DE RO RE
Figure 25. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Typical Half-Duplex RS-485 Network
A
Y
120Ω
120Ω
120Ω
120Ω
RO
RE
R
DI
D
B
Z
Z
B
DE
DE
RE
RO
DI
R
D
Y
A
Y
Z
B
A
Y
Z
B
A
R
R
D
DI
D
DI
MAX488E
MAX489E
MAX490E
MAX491E
DE RE RO
DE RE RO
NOTE: RE AND DE ON MAX489E/MAX491E ONLY.
Figure 26. MAX488E–MAX491E Full-Duplex RS-485 Network
______________________________________________________________________________________ 15
±1 5 k V ES D-P ro t e c t e d , S le w -Ra t e -Lim it e d ,
Lo w -P o w e r, RS -4 8 5 /RS -4 2 2 Tra n s c e ive rs
___________________________________________Ord e rin g In fo rm a t io n (c o n t in u e d )
PART
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
8 Plastic DIP
8 SO
PART
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
MAX483ECPA
MAX483ECSA
MAX483EEPA
MAX483EESA
MAX485ECPA
MAX485ECSA
MAX485EEPA
MAX485EESA
MAX487ECPA
MAX487ECSA
MAX487EEPA
MAX487EESA
MAX488ECPA
MAX488ECSA
MAX488EEPA
MAX488EESA
MAX489ECPD
MAX489ECSD
MAX489EEPD
MAX489EESD
MAX490ECPA
MAX490ECSA
MAX490EEPA
MAX490EESA
MAX491ECPD
MAX491ECSD
MAX491EEPD
MAX491EESD
MAX1487ECPA
MAX1487ECSA
MAX1487EEPA
MAX1487EESA
14 Plastic DIP
14 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
14 Plastic DIP
14 SO
8 Plastic DIP
8 SO
14 Plastic DIP
14 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
___________________Ch ip In fo rm a t io n
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.
35–9/MAX1487E
16 __________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 (4 0 8 ) 7 3 7 -7 6 0 0
© 1996 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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