MAX3483_V01 [MAXIM]
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers;
| 型号： | MAX3483_V01 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers |
| 文件： | 总17页 (文件大小：3130K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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MAX3483/MAX3485/
MAX3486/MAX3488/
MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
General Description
Features
● Operate from a Single 3.3V Supply—
The MAX3483, MAX3485, MAX3486, MAX3488,
MAX3490, and MAX3491 are 3.3V, low-power transceivers for
RS-485 and RS-422 communication. Each part contains
one driver and one receiver. The MAX3483 and MAX3488
feature slew-rate-limited drivers that minimize EMI and
reduce reflections caused by improperly terminated
cables, allowing error-free data transmission at data rates
up to 250kbps. The partially slew-rate-limited MAX3486
transmits up to 2.5Mbps. The MAX3485, MAX3490, and
MAX3491 transmit at up to 10Mbps.
No Charge Pump!
● Interoperable with +5V Logic
● 8ns Max Skew (MAX3485/MAX3490/MAX3491)
● Slew-Rate Limited for Errorless Data Transmission
(MAX3483/MAX3488)
● 2nA Low-Current Shutdown Mode
(MAX3483/MAX3485/MAX3486/MAX3491)
● -7V to +12V Common-Mode Input Voltage Range
● Allows up to 32 Transceivers on the Bus
Drivers are short-circuit current-limited and are protected
against excessive power dissipation by thermal shutdown
circuitry that places the driver outputs into a high-imped-
ance state. The receiver input has a fail-safe feature that
guarantees a logic-high output if both inputs are open
circuit.
● Full-Duplex and Half-Duplex Versions Available
● Industry Standard 75176 Pinout
(MAX3483/MAX3485/MAX3486)
● Current-Limiting and Thermal Shutdown for Driver
Overload Protection
The MAX3488, MAX3490, and MAX3491 feature full-
duplex communication, while the MAX3483, MAX3485, and
MAX3486 are designed for half-duplex communication.
Ordering Information
PART
TEMP. RANGE
0°C to +70°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
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 Plastic DIP
8 SO
MAX3483CPA
MAX3483CSA
MAX3483C/D
MAX3483EPA
MAX3483ESA
MAX3485CPA
MAX3485CSA
MAX3485C/D
MAX3485EPA
MAX3485ESA
Applications
● Low-Power RS-485/RS-422 Transceivers
● Telecommunications
● Transceivers for EMI-Sensitive Applications
● Industrial-Control Local Area Networks
Dice*
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
Ordering Information continued at end of data sheet.
* Contact factory for for dice specifications.
Selection Table
GUARANTEED
DATA RATE
(Mbps)
SUPPLY
VOLTAGE
(V)
DRIVER/
RECEIVER
ENABLE
SHUTDOWN
CURRENT
(nA)
PART
NUMBER
HALF/FULL
DUPLEX
SLEW-RATE
LIMITED
PIN
COUNT
MAX3483
MAX3485
MAX3486
MAX3488
MAX3490
MAX3491
0.25
10
Half
Half
Half
Full
Full
Full
Yes
No
Yes
Yes
Yes
No
2
2
8
8
2.5
0.25
10
Yes
Yes
No
2
8
3.0 to 3.6
—
—
2
8
No
8
10
No
Yes
14
19-0333; Rev 1; 5/19
MAX3483/MAX3485/
MAX3486/MAX3488/
MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
Absolute Maximum Ratings
Supply Voltage (VCC) .............................................................7V
Control Input Voltage (RE, DE).................................-0.3V to 7V
Driver Input Voltage (DI)............................................-0.3V to 7V
Driver Output Voltage (A, B, Y, Z) ........................-7.5V to 12.5V
Receiver Input Voltage (A, B)...............................-7.5V to 12.5V
14-Pin Plastic DIP (derate 10mW/°C above +70°C) ...800mW
14-Pin SO (derate 8.33mW/°C above +70°C).............667mW
Operating Temperature Ranges
MAX34_ _C_ _...................................................0°C to +70°C
MAX34_ _E_ _ ............................................... -40°C to +85°C
Junction Temperature......................................................+160°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
Receiver Output Voltage (RO) ................. -0.3V to (V
+ 0.3V)
CC
Continuous Power Dissipation (T = +70°C)
A
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ..727mW
8-Pin SO (derate 5.88mW/°C above +70°C)...............471mW
Package Information
14 SOIC
PACKAGE CODE
S14+1
Outline Number
21-0041
90-0112
Land Pattern Number
Thermal Resistance, Single-Layer Board:
Junction to Ambient (θ
)
120
37
JA
Junction to Case (θ
)
JA
Thermal Resistance, Four-Layer Board:
Junction to Ambient (θ
)
84
34
JA
Junction to Case (θ
)
JA
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board.
For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
Maxim Integrated
│ 2
www.maximintegrated.com
MAX3483/MAX3485/
MAX3486/MAX3488/
MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
DC Electrical Characteristics
(V
= 3.3V ±0.3V, T = T
to T
, unless otherwise noted. Typical values are at T = +25°C)
CC
A
MIN
MAX A
PARAMETER
SYMBOL
CONDITIONS
R = 100Ω (RS-422), Figure 4
MIN
2.0
1.5
1.5
TYP
MAX UNITS
L
Differential Driver Output
V
R = 54Ω (RS-485), Figure 4
V
OD
L
R = 60Ω (RS-485), V
= 3.3V, Figure 5
L
CC
Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
(Note 1)
ΔV
R = 54Ω or 100Ω, Figure 4
0.2
V
OD
L
Driver Common-Mode Output
Voltage
V
R = 54Ω or 100Ω, Figure 4
3
V
V
OC
L
Change in Magnitude of
Common-Mode Output Voltage
(Note 1)
ΔV
R = 54Ω or 100Ω, Figure 4
0.2
OC
L
Input High Voltage
Input Low Voltage
Logic Input Current
V
DE, DI, RE
DE, DI, RE
DE, DI, RE
2.0
V
V
IH
V
0.8
±2
IL
I
μA
IN1
V
V
V
V
V
V
= 12V
= -7V
1.0
-0.8
20
-20
1
DE = 0V,
IN
Input Current (A, B)
I
mA
IN2
V
= 0V or 3.6V
CC
IN
= 12V
= -7V
= 12V
= -7V
DE = 0V, RE = 0V,
= 0V or 3.6V, MAX3491
OUT
OUT
OUT
OUT
Output Leakage (Y, Z)
I
I
μA
O
V
CC
Output Leakage (Y, Z)
in Shutdown Mode
DE = 0V, RE = V
,
CC
μA
O
V
= 0V or 3.6V, MAX3491
-1
CC
Receiver Differential
Threshold Voltage
V
-7V ≤ V
≤ 12V
-0.2
0.2
V
TH
CM
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
ΔV
V
= 0V
50
mV
V
TH
CM
OUT
OUT
V
I
I
= -1.5mA, V = 200mV, Figure 6
V
- 0.4
OH
ID
CC
V
= 2.5mA, V = 200mV, Figure 6
0.4
±1
V
OL
ID
Three-State (High Impedance)
Output Current at Receiver
I
V
= 3.6V, 0V ≤ V
≤ V
CC
μA
kΩ
OZR
CC
OUT
Receiver Input Resistance
R
-7V ≤ V
≤ 12V
12
IN
CM
DE = V
RE = 0V or V
,
CC
1.1
0.95
0.002
2.2
1.9
1
No load,
DI = 0V or V
CC
Supply Current
I
mA
CC
CC
DE = 0V,
RE = 0V
Supply Current in Shutdown
Mode
I
DE = 0V, RE = V , DI = V or 0V
CC
µA
mA
mA
SHDN
CC
V
V
= -7V
= 12V
-250
250
Driver Short-Circuit Output
Current
OUT
I
I
OSD
OSR
OUT
Receiver Short-Circuit Output
Current
0V ≤ V
≤ V
±8
±60
RO
CC
Maxim Integrated
│ 3
www.maximintegrated.com
MAX3483/MAX3485/
MAX3486/MAX3488/
MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
Driver Switching Characteristics—MAX3485, MAX3490, and MAX3491
(V
= 3.3V, T = +25°C)
CC
A
PARAMETER
SYMBOL
CONDITIONS
R = 60Ω, Figure 7
MIN
1
TYP
22
8
MAX UNITS
Driver Differential Output Delay
t
35
25
35
35
8
ns
ns
ns
ns
ns
DD
L
Driver Differential Output Transition Time
Driver Propagation Delay, Low-to-High Level
Driver Propagation Delay, High-to-Low Level
t
R = 60Ω, Figure 7
3
TD
L
t
R = 27Ω, Figure 8
7
22
22
PLH
L
t
R = 27Ω, Figure 8
7
PHL
L
|t
- t
| Driver Propagation Delay Skew (Note 2)
t
R = 27Ω, Figure 8
L
PLH PHL
PDS
DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3485/MAX3491 only)
Driver Output Enable Time to Low Level
t
R = 110Ω, Figure 10
45
45
90
90
ns
ns
ns
ns
ns
ns
PZL
L
Driver Output Enable Time to High Level
t
t
R = 110Ω, Figure 9
L
PZH
PHZ
Driver Output Disable Time from High Level
Driver Output Disable Time from Low Level
Driver Output Enable Time from Shutdown to Low Level
Driver Output Enable Time from Shutdown to High Level
R = 110Ω, Figure 9
40
80
L
t
R = 110Ω, Figure 10
40
80
PLZ
PSL
PSH
L
t
R = 110Ω, Figure 10
650
650
900
900
L
t
R = 110Ω, Figure 9
L
Driver Switching Characteristics—MAX3486
(V
= 3.3V, T = +25°C)
CC
A
PARAMETER
SYMBOL
CONDITIONS
MIN
24
TYP
48
MAX UNITS
Driver Differential Output Delay
t
R = 60Ω, Figure 7
70
60
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
DD
L
Driver Differential Output Transition Time
Driver Propagation Delay, Low-to-High Level
Driver Propagation Delay, High-to-Low Level
t
R = 60Ω, Figure 7
15
35
TD
L
t
R = 27Ω, Figure 8
20
48
70
PLH
L
t
R = 27Ω, Figure 8
20
48
70
PHL
PDS
L
|t
- t
| Driver Propagation Delay Skew (Note 2)
t
R = 27Ω, Figure 8
11
PLH PHL
L
Driver Output Enable Time to Low Level
t
R = 110Ω, Figure 10
55
55
100
100
80
PZL
PZH
PHZ
L
Driver Output Enable Time to High Level
t
t
R = 110Ω, Figure 9
L
Driver Output Disable Time from High Level
Driver Output Disable Time from Low Level
Driver Output Enable Time from Shutdown to Low Level
Driver Output Enable Time from Shutdown to High Level
R = 110Ω, Figure 9
45
L
t
R = 110Ω, Figure 10
45
80
PLZ
PSL
PSH
L
t
R = 110Ω, Figure 10
700
700
1000
1000
L
t
R = 110Ω, Figure 9
L
Maxim Integrated
│ 4
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MAX3483/MAX3485/
MAX3486/MAX3488/
MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
Driver Switching Characteristics—MAX3483 and MAX3488
(V
= 3.3V, T = +25°C)
CC
A
PARAMETER
SYMBOL
CONDITIONS
R = 60Ω, Figure 7
MIN
600
400
700
700
TYP
900
MAX UNITS
Driver Differential Output Delay
t
1400
1200
1500
1500
ns
ns
ns
ns
ns
DD
L
Driver Differential Output Transition Time
Driver Propagation Delay, Low-to-High Level
Driver Propagation Delay, High-to-Low Level
t
R = 60Ω, Figure 7
700
TD
L
t
R = 27Ω, Figure 8
1000
1000
100
PLH
L
t
R = 27Ω, Figure 8
L
PHL
|t
- t
| Driver Propagation Delay Skew (Note 2)
t
R = 27Ω, Figure 8
L
PLH PHL
PDS
DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3485/MAX3491 only)
Driver Output Enable Time to Low Level
t
R = 110Ω, Figure 10
900
600
50
1300
800
80
ns
ns
ns
ns
ns
ns
PZL
L
Driver Output Enable Time to High Level
t
t
R = 110Ω, Figure 9
L
PZH
PHZ
Driver Output Disable Time from High Level
Driver Output Disable Time from Low Level
Driver Output Enable Time from Shutdown to Low Level
Driver Output Enable Time from Shutdown to High Level
R = 110Ω, Figure 9
L
t
R = 110Ω, Figure 10
50
80
PLZ
PSL
PSH
L
t
R = 110Ω, Figure 10
1.9
2.2
2.7
3.0
L
t
R = 110Ω, Figure 9
L
Receiver Switching Characteristics
(V
= 3.3V, T = +25°C)
CC
A
PARAMETER
SYMBOL
t
CONDITIONS
MIN
TYP
MAX UNITS
MAX3483/MAX3485/MAX3486/MAX3491 only
(Note 3)
Time to Shutdown
80
190
300
ns
ns
SHDN
V
= 0V to 3.0V, C = 15pF, Figure 11
25
25
25
25
65
75
65
75
90
120
90
Receiver Propagation Delay,
Low-to-High Level
ID
L
t
RPLH
MAX3483/MAX3488
= 0V to 3.0V, C = 15pF, Figure 11
V
Receiver Propagation Delay,
High-to-Low Level
ID
L
t
ns
ns
RPHL
RPDS
MAX3483/MAX3488
= 0V to 3.0V, C = 15pF, Figure 11
120
10
V
|t
- t
| Receiver
ID
L
PLH PHL
t
Propagation Delay Skew
MAX3483/MAX3488
20
Receiver Output Enable Time
to Low Level
C = 15pF, Figure 12,
L
MAX3483/MAX3485/MAX3486/MAX3491 only
t
25
25
50
50
ns
ns
ns
ns
ns
ns
PRZL
PRZH
PRHZ
Receiver Output Enable Time
to High Level
C = 15pF, Figure 12,
L
MAX3483/MAX3485/MAX3486/MAX3491 only
t
t
Receiver Output Disable
Time from High Level
C = 15pF, Figure 12,
L
MAX3483/MAX3485/MAX3486/MAX3491 only
25
45
Receiver Output Disable
Time from Low Level
C = 15pF, Figure 12,
L
MAX3483/MAX3485/MAX3486/MAX3491 only
t
25
45
PRLZ
PRSL
PRSH
Receiver Output Enable Time
from Shutdown to Low Level
C = 15pF, Figure 12,
L
MAX3483/MAX3485/MAX3486/MAX3491 only
t
720
720
1400
1400
Receiver Output Enable Time
from Shutdown to High Level
C = 15pF, Figure 12,
L
MAX3483/MAX3485/MAX3486/MAX3491 only
t
Note 1: ΔV
and ΔV
are the changes in V
and V , respectively, when the DI input changes state.
OD
OC
OD OC
Note 2: Measured on |t
(Y) - t
(Y)| and |t
(Z) - t
(Z)|.
PLH
PHL
PLH
PHL
Note 3: The transceivers are put into shutdown by bringing RE high and DE low. If the inputs are in this state for less than 80ns,
the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 300ns, the parts are guaranteed to
have entered shutdown. See Low-Power Shutdown Mode section.
Maxim Integrated
│ 5
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MAX3483/MAX3485/
MAX3486/MAX3488/
MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
Typical Operating Characteristics
(V
= 3.3V, T = +25°C, unless otherwise noted.)
A
CC
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
25
-20
-18
-16
-14
-12
-10
-8
3.30
3.25
I
= 1.5mA
RO
20
3.20
3.15
15
10
5
3.10
3.05
3.00
-6
-4
-2
0
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
OUTPUT LOW VOLTAGE (V)
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
OUTPUT HIGH VOLTAGE (V)
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
DRIVER DIFFERENTIAL OUTPUT
VOLTAGE vs.TEMPERATURE
100
90
80
70
60
50
40
30
0.8
0.7
0.6
0.5
2.6
2.5
I
= 2.5mA
R = 54Ω
RO
2.4
2.3
2.2
2.1
0.4
0.3
0.2
0.1
0
2.0
1.9
1.8
1.7
1.6
20
10
0
-40 -20
0
20
40
60
80 100
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
DIFFERENTIAL OUTPUT VOLTAGE (V)
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
OUTPUT CURRENT vs.
DRIVER OUTPUT LOW VOLTAGE
OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
175
-100
-80
150
125
100
75
-60
-40
-20
0
50
25
0
0
2
4
6
8
10
12
0
1
2
3
4
5
-7 -6 -5 -4 -3 -2 -1
OUTPUT LOW VOLTAGE (V)
OUTPUT HIGH VOLTAGE (V)
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│ 6
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MAX3483/MAX3485/
MAX3486/MAX3488/
MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
Typical Operating Characteristics (continued)
(V
= 3.3V, T = +25°C, unless otherwise noted.)
A
CC
SUPPLY CURRENT
vs. TEMPERATURE
SHUTDOWN CURRENT
vs. TEMPERATURE
1.2
100
90
X = DON’T CARE
1.1
80
70
60
DE = V , RE = X
CC
1.0
0.9
50
DE = 0, RE = 0
40
30
20
10
0
0.8
0.7
-40 -20
0
20
40
60
80 100
-40 -20
0
20
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
Pin Description
PIN
MAX3483/
MAX3485/
MAX3486
NAME
FUNCTION
MAX3488/
MAX3490
MAX3491
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 low; RO is high
impedance when RE is high. If RE is high and DE is low, the device
will enter a low-power shutdown mode.
—
RE
Driver Output Enable. The driver outputs are enabled by bringing DE
high. They are high impedance when DE is low. If RE is high and DE
is low, the device will enter a low-power shutdown mode. If the driver
outputs are enabled, the parts function as line drivers. While they are
high impedance, they function as line receivers if RE is low.
3
4
—
3
4
5
DE
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
—
—
6
4
5
6, 7
9
GND
Y
Ground
Noninverting Driver Output
6
10
Z
Inverting Driver Output
—
8
—
A
Noninverting Receiver Input and Noninverting Driver Output
Noninverting Receiver Input
—
7
12
A
—
7
—
B
Inverting Receiver Input and Inverting Driver Output
Inverting Receiver Input
—
8
11
B
1
13, 14
1, 8
V
Positive Supply: 3.0V ≤ V
≤ 3.6V
CC
CC
—
—
N.C.
No Connect—not internally connected
Maxim Integrated
│ 7
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MAX3483/MAX3485/
MAX3486/MAX3488/
MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
TOP VIEW
MAX3483
DE
MAX3485
MAX3486
R
R
1
2
3
4
RO
RE
DE
DI
1
2
3
4
RO
RE
DE
DI
8
8
7
6
5
V
V
D
CC
DI
CC
B
B
A
7
B
Rt
Rt
6
A
A
RO
R
D
D
5
GND
GND
RE
NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.
DIP/SO
Figure 1. MAX3483/MAX3485/MAX3486 Pin Configuration and Typical Operating Circuit
V
CC
V
TOP VIEW
CC
1
MAX3488
MAX3490
Y
Z
5
6
3
2
Rt
DI
RO
DI
D
R
V
1
2
3
4
R
8
7
6
5
A
B
Z
Y
CC
RO
DI
8
7
A
B
Rt
RO
R
D
GND
D
DIP/SO
4
GND
GND
Figure 2. MAX3488/MAX3490 Pin Configuration and Typical Operating Circuit
DE
V
V
RE
CC
TOP VIEW
CC
MAX3491
4
13, 14
N.C.
1
2
3
4
5
6
7
14
13
12
11
10
9
V
V
CC
CC
9
Y
R
5
Rt
RO
RE
RO
DI
DI
D
R
10
A
B
Z
Y
Z
A
DE
12
11
DI
2
Rt
RO
R
D
D
GND
GND
B
8
N.C.
1, 8
N.C.
3
6, 7
DIP/SO
RE GND
GND DE
Figure 3. MAX3491 Pin Configuration and Typical Operating Circuit
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375Ω
R
L
2
V
=
CM
V
OD
D
-7V to +12V
R
L
V
OD
D
R
L
V
OC
V
CC
2
V
CC
375Ω
Figure 4. Driver V
and V
Figure 5. Driver V with Varying Common-Mode Voltage
OD
OD
OC
V
ID
R
0V
V
OL
V
OH
I
OL
I
OH
(+)
(-)
Figure 6. Receiver V
and V
OH
OL
3V
IN
1.5V
1.5V
DO
C
C
L
0V
OUT
D
R =
L
60Ω
t
t
DO
GENERATOR
(NOTE 4)
50Ω
≈ 2.0V
90%
90%
V
CC
50%
10%
50%
10%
OUT
L
≈ -2.0V
C = 15pF (NOTE 5)
L
t
t
TD
TD
Figure 7. Driver Differential Output Delay and Transition Times
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3V
V
OM
IN
1.5V
1.5V
PLH
R
= 27Ω
0V
L
S1
t
t
t
t
PHL
OUT
D
V
OH
OL
GENERATOR
Y
OUT
(NOTE 4)
50Ω
C
L
(NOTE 5)
= 15pF
V
V
V
OM
OM
V
CC
V
PHL
PLH
V
OH
+ V
V
OM
=
OL ≈ 1.5V
2
V
V
OH
Z
OUT
V
OM
OM
OL
Figure 8. Driver Propagation Times
3V
S1
OUT
0V OR 3V
D
IN
1.5V
1.5V
0V
V
R = 110Ω
L
C = 50pF
(NOTE 5)
L
t
t
PHZ
PZH
GENERATOR
(NOTE 4)
OH
50Ω
0.25V
OUT
V
OM
V
OH
+ V
V
OM
=
OL ≈ 1.5V
0V
2
Figure 9. Driver Enable and Disable Times (t
, t
, t
)
PZH PSH PHZ
V
CC
3V
R = 110Ω
L
IN
1.5V
1.5V
S1
0V
0V OR 3V
OUT
D
t
t
PLZ
PSL
C = 50pF
L
(NOTE 5)
V
CC
OL
GENERATOR
(NOTE 4)
OUT
V
OM
50Ω
0.25V
V
Figure 10. Driver Enable and Disable Times (t
, t
, t
)
PZL PSL PLZ
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3.0V
OUT
V
ID
R
IN
1.5V
1.5V
GENERATOR
(NOTE 4)
50Ω
C = 15pF
L
0V
(NOTE 5)
t
t
RPHL
RPLH
V
CC
1.5V
0V
V
OM
V
OM
OUT
V
CC
2
V
OM
=
0V
Figure 11. Receiver Propagation Delay
S1
S3
1.5V
1k
V
CC
-1.5V
V
ID
R
S2
C
L
(NOTE 5)
GENERATOR
(NOTE 4)
50Ω
3V
0V
3V
S1 OPEN
S2 CLOSED
S3 = 1.5V
S1 CLOSED
S2 OPEN
S3 = -1.5V
IN
IN
1.5V
1.5V
0V
t
t
t
t
PRZH
PRSH
PRZL
PRSL
V
V
OH
CC
OL
OUT
OUT
1.5V
1.5V
0V
V
3V
0V
3V
0V
S1 OPEN
S2 CLOSED
S3 = 1.5V
S1 CLOSED
S2 OPEN
S3 = -1.5V
IN
1.5V
IN
1.5V
t
PRHZ
t
PRLZ
V
V
OH
CC
OL
OUT
0.25V
0.25V
OUT
0V
V
Figure 12. Receiver Enable and Disable Times
Note 4: The input pulse is supplied by a generator with the following characteristics: PRR = 250kHz, 50% duty cycle, tr ≤ 6.0ns, Z = 50Ω.
O
Note 5: C includes probe and stray capacitance.
L
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Function Tables
Applications Information
The MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/
MAX3491 are low-power transceivers for RS-485 and
RS-422 communications. The MAX3483 and MAX3488
can transmit and receive at data rates up to 250kbps, the
MAX3486 at up to 2.5Mbps, and the MAX3485/MAX3490/
MAX3491 at up to 10Mbps. The MAX3488/MAX3490/
MAX3491 are full-duplex transceivers, while the MAX3483/
MAX3485/MAX3486 are half-duplex. Driver Enable (DE)
and Receiver Enable (RE) pins are included on the
MAX3483/MAX3485/MAX3486/MAX3491. When disabled,
the driver and receiver outputs are high impedance.
Devices with Receiver/Driver Enable
(MAX3483/MAX3485/MAX3486/MAX3491)
Table 1. Transmitting
INPUTS
OUTPUTS
MODE
RE
X
DE
1
DI
1
B*
A*
1
0
Normal
Normal
X
1
0
1
0
0
0
X
X
High-Z
High-Z
High-Z
High-Z
Normal
1
0
Shutdown
Reduced EMI and Reflections
(MAX3483/MAX3486/MAX3488)
* B and A outputs are Z and Y, respectively, for full-duplex part
(MAX3491).
X = Don’t care; High-Z = High impedance
The MAX3483/MAX3488 are slew-rate limited, minimizing
EMI and reducing reflections caused by improperly
terminated cables. Figure 13 shows both the driver output
waveform of a MAX3485/MAX3490/MAX3491 transmitting
a 125kHz signal and the Fourier analysis of that wave-
form. High-frequency harmonics with large amplitudes are
evident. Figure 14 shows the same information, but for
the slew-rate-limited MAX3483/MAX3488 transmitting the
same signal. The high-frequency harmonics have much
lower amplitudes, and the potential for EMI is significantly
reduced.
Table 2. Receiving
INPUTS
DE
OUTPUTS
MODE
RE
0
A, B
≥ +0.2V
≤ -0.2V
Inputs Open
X
B*
0*
0*
0*
0
1
Normal
Normal
0
0
1
0
Normal
1
High-Z
Shutdown
* DE is a “don’t care” (x) for the full-duplex part (MAX3491).
X = Don’t care; High-Z = High impedance
Low-Power Shutdown Mode
(MAX3483/MAX3485/MAX3486/MAX3491)
Devices without Receiver/Driver Enable
(MAX3488/MAX3490)
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 (high
impedance). In shutdown, the devices typically draw only
2nA of supply current.
Table 3. Transmitting Table 4. Receiving
INPUT
OUTPUTS
INPUTS
A, B
OUTPUT
DI
1
Z
Y
1
0
RO
1
For these devices, the t
and t
enable times
PSH
PSL
assume the part was in the low-power shutdown mode;
the t and t enable times assume the receiver or
0
1
≥ +0.2V
≤ -0.2V
PZH
PZL
0
0
driver was disabled, but the part was not shut down.
Inputs Open
1
10dB/div
10dB/div
0Hz
500kHz/div
5MHz
0Hz
500kHz/div
5MHz
Figure 13. Driver Output Waveform and FFT Plot of MAX3485/
MAX3490/MAX3491 Transmitting a 125kHz Signal
Figure 14. Driver Output Waveform and FFT Plot of MAX3483/
MAX3488 Transmitting a 125kHz Signal
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B
1V/div
DI
2V/div
A
1V/div
Z
1V/div
RO
Y
2V/div
1V/div
20ns/div
20ns/div
Figure 15. MAX3485/MAX3490/MAX3491 Driver Propagation
Delay
Figure 16. MAX3485/MAX3490/MAX3491 Receiver
Propagation Delay Driven by External RS-485 Device
B
1V/div
DI
2V/div
A
1V/div
Z
1V/div
Y
RO
2V/div
1V/div
1ms/div
1ms/div
Figure 17. MAX3483/MAX3488 Driver Propagation Delay
Figure 18. MAX3483/MAX3488 Receiver Propagation Delay
DI
DI
5V/div
5V/div
V - V
V - V
Y
Z
Y
Z
2V/div
2V/div
RO
RO
5V/div
5V/div
2ms/div
2µs/div
Figure 19. MAX3483/MAX3488 System Differential Voltage at
125kHz Driving 4000 ft of Cable
Figure 20. MAX3485/MAX3490/MAX3491 System Differential
Voltage at 125kHz Driving 4000 ft of Cable
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120Ω
120Ω
DE
B
B
DI
D
D
DI
DE
B
A
A
B
A
A
RO
RO
R
R
RE
RE
R
R
D
D
MAX3483
MAX3485
MAX3486
DI
DE RO RE
DI
DE RO RE
Figure 21. MAX3483/MAX3485/MAX3486 Typical RS-485 Network
Driver Output Protection
Line Length vs. Data Rate
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-impedance
state if the die temperature rises excessively.
The RS-485/RS-422 standard covers line lengths up to
4000 feet. For line lengths greater than 4000 feet, see
Figure 23.
Figures 19 and 20 show the system differential voltage
for parts driving 4000 feet of 26AWG twisted-pair wire at
125kHz into 120Ω loads.
Typical Applications
The MAX3483, MAX3485, MAX3486, MAX3488,
MAX3490, and MAX3491 transceivers are designed
for bidirectional data communications on multipoint bus
transmission lines. Figures 21 and 22 show typical net-
work applications circuits. These parts can also be used
as line repeaters, with cable lengths longer than 4000
feet, as shown in Figure 23.
Propagation Delay
Figures 15–18 show the typical propagation delays. Skew
time is simply the difference between the low-to-high and
high-to-low propagation delay. Small driver/receiver skew
times help maintain a symmetrical mark-space ratio (50%
duty cycle).
The receiver skew time, |t
- t
|, is under 10ns
PRLH
PRHL
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 pos-
sible. The slew-rate-limited MAX3483/MAX3488 and the
partially slew-rate-limited MAX3486 are more tolerant of
imperfect termination.
(20ns for the MAX3483/MAX3488). The driver skew
times are 8ns for the MAX3485/MAX3490/MAX3491,
11ns for the MAX3486, and typically under 100ns for the
MAX3483/MAX3488.
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A
Y
120Ω
120Ω
RO
RE
R
DI
D
B
Z
Z
B
DE
DE
RE
RO
120Ω
120Ω
DI
R
D
Y
A
Y
Z
B
A
Y
Z
B
A
R
R
MAX3488
MAX3490
MAX3491
D
D
DI
DE RERO
DI
DE RERO
NOTE: RE AND DE ON MAX3491 ONLY.
Figure 22. MAX3488/MAX3490/MAX3491 Full-Duplex RS-485 Network
MAX3488
MAX3490
MAX3491
A
120Ω
RO
RE
R
DATA IN
B
DE
Z
Y
DI
120Ω
DATA OUT
D
NOTE: RE AND DE ON MAX3491 ONLY.
Figure 23. Line Repeater for MAX3488/MAX3490/MAX3491
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Ordering Information (continued)
Chip Topography
MAX3486CPA
MAX3486CSA
MAX3486C/D
MAX3486EPA
MAX3486ESA
MAX3488CPA
MAX3488CSA
MAX3488C/D
MAX3488EPA
MAX3488ESA
MAX3490CPA
MAX3490CSA
MAX3490C/D
MAX3490EPA
MAX3490ESA
MAX3491CPD
MAX3491CSD
MAX3491C/D
MAX3491EPD
MAX3491ESD
0°C to +70°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
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
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
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
8 Plastic DIP
V
CC
8 SO
Dice*
8 Plastic DIP
8 SO
RO
RE
8 Plastic DIP
8 SO
A
Dice*
B
8 Plastic DIP
8 SO
Z/B
8 Plastic DIP
8 SO
0.146"
(3.71mm)
Dice*
8 Plastic DIP
8 SO
14 Plastic DIP
14 SO
DE
DI
Dice*
Y/A
14 Plastic DIP
14 SO
GND
* Contact factory for for dice specifications.
GND
0.086"
(2.18mm)
TRANSISTOR COUNT: 810
SUBSTRATE CONNECTED TO GROUND
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Revision History
REVISION REVISION
PAGES
DESCRIPTION
CHANGED
NUMBER
DATE
0
12/94
Initial release
—
Updated Absolute Maximum Ratings and Selection table, added Package
Information section
1
5/19
1, 2
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Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated 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.
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