MAX13444EASA+T [MAXIM]
Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, BICMOS, PDSO8, 0.150 INCH, LEAD FREE, MS-012AA, SOP-8;
| 型号： | MAX13444EASA+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, BICMOS, PDSO8, 0.150 INCH, LEAD FREE, MS-012AA, SOP-8 驱动 信息通信管理 光电二极管 接口集成电路 驱动器 |
| 文件： | 总18页 (文件大小：1351K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
General Description
Features
The MAX13442E/MAX13444E are fault-protected RS-485
and J1708 transceivers that feature ±80V protection
from signal faults on communication bus lines. The
MAX13442E/MAX13444E feature a reduced slew-rate
driver that minimizes EMI and reflections, allowing error-
free transmission up to 250kbps. The MAX13443E driver
can transmit up to 10Mbps. The high-speed MAX13443E
RS-485 transceiver features ±60V protection from signal
faults on communication bus lines. These transceivers
feature foldback current limit. Each device contains one
differential line driver with three-state output and one dif-
ferential line receiver with three-state input. The 1/4-unit-
load receiver input impedance allows up to 128 transceiv-
ers on a single bus. The devices operate from a 5V sup-
ply. True fail-safe inputs guarantee a logic-high receiver
output when the receiver inputs are open, shorted, or
connected to an idle data line.
● ±15kV ESD Protection
● ±80V Fault Protection (±60V MAX13443E)
● Guaranteed 10Mbps Data Rate (MAX13443E)
● Hot-Swappable for Telecom Applications
● True Fail-Safe Receiver Inputs
● Enhanced Slew-Rate-Limiting Facilitates Error-Free
Data Transmission (MAX13442E/MAX13444E)
● Allow Up to 128 Transceivers on the Bus
● -7V to +12V Common-Mode Input Range
● ±6mA FoldBack Current Limit
● Industry-Standard Pinout
Applications
● RS-422/RS-485
Communications
● Truck and Trailer
Applications
● Telecommunications
Systems
● Automotive Applications
● HVAC Controls
Hot-swap circuitry eliminates false transitions on the data
bus during circuit initialization or connection to a live back-
plane. Short-circuit current-limiting and thermal-shutdown
circuitry protect the driver against excessive power dis-
sipation, and on-chip ±15kV ESD protection eliminates
costly external protection devices.
● Industrial Networks
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX13442EASA+
MAX13443EASA+
MAX13444EASA/V+T
-40°C to +125°C 8 SO
The MAX13442E/MAX13443E/MAX13444E are available
in an 8-pin SO package and are specified over the auto-
motive temperature range.
-40°C to +125°C 8 SO
-40°C to +125°C 8 SO
+Denotes lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
T = Tape and reel.
Selector Guide
DATA RATE
(Mbps)
FAULT
LOW-POWER RECEIVER/DRIVER TRANSCEIVERS
PART
TYPE
HOT SWAP
PROTECTION (V) SHUTDOWN
ENABLE
Yes
ON BUS
128
MAX13442E RS-485
MAX13443E RS-485
MAX13444E J1708
0.25
10
±80
±60
±80
Yes
Yes
Yes
Yes
Yes
Yes
128
0.25
Yes
128
Yes (only RE)
Pin Configurations and Typical Operating Circuits
DE
TOP VIEW
MAX13442E
MAX13443E
+
+
RO
RE
DE
DI
R
R
RO
RE
DE
DI
1
2
3
4
1
2
3
4
V
8
8
7
6
5
V
D
CC
CC
DI
B
B
7
B
R
T
R
T
6
A
A
GND
A
RO
R
D
D
GND
5
RE
SO
SO
Pin Configurations and Typical Operating Circuits continued at end of data sheet.
19-3898; Rev 3; 3/11
MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Absolute Maximum Ratings
(Voltages referenced to GND.)
Continuous Power Dissipation (T = +70°C)
A
V
........................................................................................+7V
SO (derate 7.6mW/°C above +70°C)..........................606mW
Operating Temperature Range......................... -40°C to +125°C
Storage Temperature Range............................ -65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow).......................................+260°C
CC
RE, DE, DE, DI, TXD ............................... -0.3V to (V
A, B (Note 1) (MAX13442E/MAX13444E)...........................±80V
A, B (Note 1) (MAX13443E)................................................±60V
RO ............................................................ -0.3V to (V
Short-Circuit Duration (RO, A, B)..............................Continuous
+ 0.3V)
CC
+ 0.3V)
CC
Note 1: During normal operation, a termination resistor must be connected between A and B in order to guarantee overvoltage protec-
tion up to the absolute maximum rating of this device. When not in operation, these devices can withstand fault voltages up
to the maximum rating without a termination resistor and will not be damaged.
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.
(Note 2)
Package Thermal Characteristics
SO
Junction-to-Ambient Thermal Resistance (θ ) ........132°C/W
Junction-to-Case Thermal Resistance (θ )...............38°C/W
JC
JA
Note 1: 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.
DC Electrical Characteristics
(V
= +4.75V to +5.25V, T = T
A
to T
, unless otherwise noted. Typical values are at V
= +5V and T = +25°C.)
CC
MIN
MAX
CC A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Figure 1, R = 100Ω
2
V
V
L
CC
Differential Driver Output
V
V
OD
Figure 1, R = 54Ω
1.5
L
CC
Change in Magnitude of
Differential Output Voltage
ΔV
Figure 1, R = 100Ω or 54Ω (Note 3)
0.2
3
V
V
V
OD
L
Driver Common-Mode
Output Voltage
V
Figure 1, R = 100Ω or 54Ω
V
/2
OC
L
CC
Change in Magnitude of
Common-Mode Voltage
Figure 1, R = 100Ω or 54Ω (Note 3)
L
DV
0.2
OC
(MAX13442E/MAX13443E)
DRIVER LOGIC
Driver-Input High Voltage
Driver-Input Low Voltage
Driver-Input Current
V
2
V
V
DIH
V
0.8
±2
DIL
I
µA
DIN
0V ≤ V
≤ +12V
+350
OUT
Driver Short-Circuit Output
Current (Note 4)
I
mA
mA
mA
OSD
-7V ≤ V
≤ V
-350
+25
OUT
CC
(V
- 1V) ≤ V
≤ +12V (Note 4)
CC
OUT
Driver Short-Circuit Foldback
Output Current
I
OSDF
-7V ≤ V
≤ +1V (Note 4)
-25
-6
OUT
V
V
≥ +20V, R = 100Ω
+6
OUT
L
Driver-Limit Short-Circuit
Foldback Output Current
I
OSDL
≤ -15V, R = 100Ω
OUT
L
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MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
DC Electrical Characteristics (continued)
(V
= +4.75V to +5.25V, T = T
to T
, unless otherwise noted. Typical values are at V
= +5V and T = +25°C.)
CC
A
MIN
MAX
CC A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RECEIVER
V
V
V
= GND, V
= 12V
250
-150
±6
CC
A, B
A, B
receive
mode
µA
Input Current
I
= -7V
A,B
A, B
A, B
= ±80V
mA
mV
mV
Receiver-Differential Threshold
Voltage
V
-7V ≤ V
≤ +12V
-200
-50
TH
CM
Receiver-Input Hysteresis
RECEIVER LOGIC
ΔV
25
TH
Output-High Voltage
Output-Low Voltage
V
Figure 2, I
= -1.6mA
V - 0.6
CC
V
V
OH
OH
V
Figure 2, I = 1mA
0.4
OL
OL
Three-State Output Current at
Receiver
I
0V ≤ V
≤ V
CC
±1
µA
kΩ
mA
OZR
A, B
Receiver Input Resistance
R
-7V ≤ V
≤ +12V
48
IN
CM
Receiver Output Short-Circuit
Current
I
0V ≤ V
≤ V
CC
±95
OSR
RO
CONTROL
Control-Input High Voltage
V
DE, DE, RE
DE, RE
2
V
CIH
Input-Current Latch During First
Rising Edge
I
90
µA
IN
SUPPLY CURRENT
DE = V , RE = GND
CC
(MAX13442E)
(DE = RE = GND)
(MAX13444E)
30
No load,
Normal Operation
I
DI = V
mA
CC
CC
or GND
(DE = V , RE = GND)
(MAX13443E)
CC
10
20
DE = GND, RE = V
CC
(MAX13442E/MAX13443E)
DE = GND, RE = V , T = +25°C
(MAX13442E/MAX13443E)
CC
A
10
100
10
Supply Current in Shutdown
Mode
I
µA
SHDN
DE = RE = V (MAX13444E)
CC
DE = RE = V , T = +25°C (MAX13444E)
CC
A
Supply Current with Output
Shorted to ±60V
DE = GND, RE = GND, no load
output in three-state (MAX13443E)
I
±15
mA
SHRT
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MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Protection Specifications
(V
= +4.75V to +5.25V, T = T
to T
, unless otherwise noted. Typical values are at V
= +5V and T = +25°C.)
CC
A
MIN
MAX
CC A
PARAMETER
SYMBOL
CONDITIONS
MIN
±80
±60
TYP
MAX
UNITS
V
MAX13442E/
MAX13444E
A, B; R
= 0Ω,
SOURCE
Overvoltage Protection
ESD Protection
R = 54
Ω
L
MAX13443E
A, B
Human Body Model
±15
kV
Switching Characteristics (MAX13442E/MAX13444E)
(V
= +4.75V to +5.25V, T = T
to T
, unless otherwise noted. Typical values are at V
= +5V and T = +25°C.)
CC
A
MIN
MAX
CC A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Figure 3, R = 54Ω, C = 50pF (MAX13442E)
t
t
,
L
L
PLHA
Driver Propagation Delay
2000
ns
PLHB
R
R
= 60Ω, C
= 100pF (MAX13444E)
DIFF
DIFF
t
,
DPLH
Driver Differential Propagation Delay
= 54Ω, C = 50pF, Figure 4
2000
2000
ns
ns
L
L
L
t
DPHL
Driver Differential Output
Transition Time
t
,t
LH HL
R
R
= 54Ω, C = 50pF, Figure 4
200
L
= 54Ω, C = 50pF,
L
L
t
t
,
SKEWAB
Driver Output Skew
t
t
= |t
= |t
- t
|,
|
350
200
ns
SKEWAB
SKEWBA
PLHA PHLB
SKEWBA
- t
PLHB PHLA
R
= 54Ω, C = 50pF,
L
L
Differential Driver Output Skew
t
DSKEW
ns
t
= |t |
- t
DSKEW
DPLH DPHL
Maximum Data Rate
f
250
kbps
ns
MAX
Driver Enable Time to Output High
Driver Disable Time from Output High
t
R
R
= 500Ω, C = 50pF, Figure 5
2000
2000
PDZH
L
L
L
t
= 500Ω, C = 50pF, Figure 5
ns
PDHZ
L
Driver Enable Time from Shutdown to
Output High
t
R
= 500Ω, C = 50pF, Figure 5
4.2
µs
PDHS
L
L
Driver Enable Time to Output Low
t
R
R
= 500Ω, C = 50pF, Figure 6
2000
2000
ns
ns
PDZL
L
L
L
Driver Disable Time from Output Low
t
= 500Ω, C = 50pF, Figure 6
L
PDLZ
Driver Enable Time from Shutdown to
Output Low
t
R
R
C
= 500Ω, C = 50pF, Figure 6
4.2
800
µs
ns
ns
PDLS
L
L
L
L
Driver Time to Shutdown
t
= 500Ω, C = 50pF
L
SHDN
t
,
RPLH
Receiver Propagation Delay
= 20pF, V = 2V, V
ID CM
= 0V, Figure 7
2000
t
RPHL
Receiver Output Skew
t
C
R
R
R
R
R
R
= 20pF, t
= |t
- t
= 1kΩ, C = 20pF, Figure 8
|
200
2000
2000
4.2
ns
ns
ns
µs
ns
ns
ns
RSKEW
L
L
L
L
L
L
L
RSKEW
RPLH RPHL
Receiver Enable Time to Output High
Receiver Disable Time from Output High
Receiver Wake Time from Shutdown
Receiver Enable Time to Output Low
Receiver Disable Time from Output Low
Receiver Time to Shutdown
t
t
RPZH
RPHZ
L
= 1kΩ, C = 20pF, Figure 8
L
t
= 1kΩ, C = 20pF, Figure 8
L
RPWAKE
t
= 1kΩ, C = 20pF, Figure 8
2000
2000
800
RPZL
RPLZ
L
t
= 1kΩ, C = 20pF, Figure 8
L
t
= 500Ω, C = 50pF
L
SHDN
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MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Switching Characteristics (MAX13443E)
(V
= +4.75V to +5.25V, T = T
to T
, unless otherwise noted. Typical values are at V
= +5V and T = +25°C.)
CC
A
MIN
MAX
CC A
PARAMETER
SYMBOL
CONDITIONS
, C = 50pF, Figure 3
MIN
TYP
MAX
UNITS
t
,
PLHA
Driver Propagation Delay
R = 27
Ω
60
ns
L
L
t
PLHB
t
t
,
DPLH
Driver Differential Propagation Delay
R = 54
Ω
, C = 50pF, Figure 4
L
60
25
ns
ns
L
DPHL
Driver Differential Output
Transition Time
t
,t
R = 54
Ω
, CL = 50pF, Figure 4
LH HL
L
R = 54
Ω
, C = 50pF,
L
L
t
t
,
SKEWAB
Driver Output Skew
t
t
= |t
- t
|,
|
10
10
ns
ns
SKEWAB
SKEWBA
PLHA PHLB
SKEWBA
= |t - t
PLHB PHLA
R = 54Ω, C = 50pF,
L
L
Differential Driver Output Skew
t
DSKEW
t
= |t |
- t
DSKEW
DPLH DPHL
Maximum Data Rate
f
10
Mbps
ns
MAX
Driver Enable Time to Output High
Driver Disable Time from Output High
t
R
R
= 500
Ω
Ω
, C = 50pF, Figure 5
1200
1200
PDZH
PDHZ
L
L
L
t
= 500
, C = 50pF, Figure 5
ns
L
Driver Enable Time from Shutdown to
Output High
t
R = 500
Ω
, C = 50pF, Figure 5
4.2
µs
PDHS
L
L
Driver Enable Time to Output Low
Driver Disable Time from Output Low
t
R = 500
Ω
, C = 50pF, Figure 6
1200
1200
ns
ns
PDZL
L
L
t
R
R
= 500Ω, C = 50pF, Figure 6
L
PDLZ
L
L
Driver Enable Time from Shutdown to
Output Low
t
= 500Ω, C = 50pF, Figure 6
4.2
800
85
Fs
ns
ns
PDLS
L
Driver Time to Shutdown
t
R = 500Ω, C = 50pF, Figure 6
L L
SHDN
t
,
RPLH
Receiver Propagation Delay
C = 20pF, V = 2V, V
= 0V, Figure 7
L
ID
CM
t
RPHL
Receiver Output Skew
t
RSKEW
C = 20pF, t
= |t
- t
|
15
400
400
4.2
ns
ns
ns
µs
L
RSKEW
RPLH RPHL
Receiver Enable Time to Output High
Receiver Disable Time from Output High
Receiver Wake Time from Shutdown
t
R
R
= 1kΩ, C = 20pF, Figure 8
L
RPZH
RPHZ
L
L
t
= 1kΩ, C = 20pF, Figure 8
L
t
R = 1kΩ, C = 20pF, Figure 8
L L
RPWAKE
Receiver Enable Wake Time from
Shutdown
t
R
= 1kΩ, C = 20pF, Figure 8
400
ns
RPSH
L
L
Receiver Disable Time from Output Low
Receiver Time to Shutdown
t
R
R
= 1kΩ, C = 20pF, Figure 8
400
800
ns
ns
RPLZ
L
L
L
t
= 500Ω, C = 50pF
L
SHDN
Note 3: ΔV
and ΔV
are the changes in V
and V , respectively, when the DI input changes state.
OD
OC
OD OC
Note 4: The short-circuit output current applies to peak current just before foldback current limiting. The short-circuit foldback output
current applies during current limiting to allow a recovery from bus contention.
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MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Typical Operating Characteristics
(V
= +5V, T = +25°C, unless otherwise noted.)
A
CC
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
6
24
10
1
MAX13442E
DI = DE = GND
DRIVER AND RECEIVER
ENABLED
DRIVER AND RECEIVER
ENABLED
5
4
3
2
1
0
20
16
12
8
RE = V
CC
0.1
0.01
DRIVER DISABLED,
RECEIVER ENABLED
0.001
0.0001
0.00001
0.000001
DRIVER DISABLED,
RECEIVER ENABLED
4
MAX13443E
MAX13442E/MAX13444E
0
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
RECEIVER OUTPUT CURRENT
vs. OUTPUT-LOW VOLTAGE
RECEIVER OUTPUT CURRENT
vs. OUTPUT-HIGH VOLTAGE
40
35
30
25
20
15
10
5
40
35
30
25
20
15
10
5
0
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT LOW VOLTAGE (V)
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT LOW VOLTAGE (V)
RECEIVER OUTPUT VOLTAGE
vs. TEMPERATURE
DRIVER OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
R = 54Ω
L
MAX13442E
DI = GND, DE = V
VOLTAGE APPLIED
TO OUTPUT A
140
,
CC
V
, I
= 10mA
120
100
OH OUT
80
60
40
20
0
V
, I
= -10mA
OL OUT
-40 -25 -10
5
20 35 50 65 80 95 110 125
10
20
30
40
50
60
70
80
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
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MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Typical Operating Characteristics (continued)
(V
= +5V, T = +25°C, unless otherwise noted.)
A
CC
DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
DRIVER OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
100
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
R = 54Ω
L
90
80
70
60
50
40
30
20
10
0
MAX13442E
DI = GND, DE = V
VOLTAGE APPLIED
TO OUTPUT B
R = 100Ω
L
,
CC
R = 54Ω
L
MAX13442E
-40 -25 -10 5 20 35 50 65 80 95 110 125
-80
-65
-50
-35
-20
-5
DIFFERENTIAL OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
A, B CURRENT vs. A, B
VOLTAGE (TO GROUND)
3.5
3200
DRIVER DISABLED,
RECEIVER ENABLED
2800
2400
2000
1600
1200
800
3.0
2.5
2.0
1.5
1.0
0.5
0
RL = 100Ω
RL = 54Ω
400
0
-400
-800
-1200
NO LOAD
R = 54Ω
L
-1600
-2000
MAX13442E
MAX13443E
0
80
-40 -25 -10
5
20 35 50 65 80 95 110 125
-60 -40 -20
20 40 60
-80
TEMPERATURE (°C)
A, B VOLTAGE (V)
A, B CURRENT vs. A, B VOLTAGE
(TO GROUND)
2000
1600
1200
800
DRIVER DISABLED,
RECEIVER ENABLED
400
0
NO LOAD
-400
-800
-1200
-1600
-2000
R = 54Ω
L
MAX13443E
0 10 20 30 40 50 60
-60 -50 -40 -30 -20 -10
A, B VOLTAGE (V)
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MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Test Circuits and Waveforms
R
L
2
A
B
V
OD
DI
D
R
L
V
OC
V
CC
2
Figure 1. Driver V
and V
OC
OD
A
ID
B
RO
V
R
0
V
V
OL
OH
I
I
OH
OL
(+)
(-)
Figure 2. Receiver V
and V
OH
OL
3V
0V
V
OM
DI
1.5V
1.5V
R
L
A
B
2
S1
t
t
PHLA
DI
PLHA
OUT
D
V
OH
OL
GENERATOR
(NOTE 5)
50Ω
C = 50pF
L
(NOTE 6)
V
V
OM
OM
A
B
V
CC
V
t
t
PHLB
PLHB
V
OH
+ V
OL
V
=
≈ 1.5V
OM
2
V
V
OH
V
OM
V
OM
OL
Figure 3. Driver Propagation Times
3V
0V
1.5V
1.5V
DI
A
C
C
L
DI
D
OUT
t
DPHL
t
DPLH
R
L
GENERATOR
(NOTE 5)
B
50Ω
≈ 2.0V
90%
90%
V
CC
50%
10%
50%
10%
L
(A–B)
≈ -2.0V
C = 50pF (NOTE 6)
L
t
t
HL
LH
Figure 4. Driver Differential Output Delay and Transition Times
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MAX13442E/MAX13443E/
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Test Circuits and Waveforms (continued)
3V
A
S1
DI
A, B
0 OR 3V
D
DE
1.5V
1.5V
PDZH
t
B
0V
V
DE
R = 500Ω
L
t
t
PDHZ
PDHS
C = 50pF
L
(NOTE 6)
GENERATOR
(NOTE 5)
50Ω
OH
0.25V
A, B
V
OM
V
OH
+ V
OL
V
=
≈ 1.5V
OM
0V
2
Figure 5. Driver Enable and Disable Times
V
CC
3V
R = 500Ω
L
1.5V
1.5V
PDZL
DE
A
S1
t
t
DI
0V
A, B
0 OR 3V
D
t
PDLS
PDLZ
B
DE
C = 50pF
L
(NOTE 6)
V
CC
OL
GENERATOR
(NOTE 5)
A, B
V
OM
50Ω
0.25V
V
Figure 6. Driver Enable and Disable Times
2.0V
0V
A
R
O
V
ID
R
(A–B)
t
1.0V
1.0V
GENERATOR
(NOTE 5)
50W
B
C = 20pF
(NOTE 6)
L
t
RPLH
RPHL
V
CC
1.0V
0V
V
OM
V
OM
RO
0V
Figure 7. Receiver Propagation Delay
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S1
S3
+1.5V
A
B
V
CC
1kΩ
R
O
-1.5V
V
ID
R
S2
C = 20pF
L
(NOTE 6)
GENERATOR
(NOTE 5)
50Ω
3V
0V
3V
0V
S1 OPEN
S2 CLOSED
S1 CLOSED
S2 OPEN
RE
RO
RE
RO
RE
RO
1.5V
1.5V
V
= 1.5V
V
S3
= -1.5V
S3
t
RPZH
t
t
RPZL
RPSL
t
t
RPSH
RPWAKE
V
OH
V
CC
1.5V
1.5V
0V
3V
V
OL
3V
0V
S1 OPEN
S2 CLOSED
S1 CLOSED
S2 OPEN
RE
RO
1.5V
1.5V
V
= 1.5V
V
= -1.5V
S3
S3
0V
t
RPHZ
t
RPLZ
V
OH
V
CC
OL
0.5V
0.5V
0V
V
Figure 8. Receiver Enable and Disable Times
Note 5: The input pulse is supplied by a generator with the following characteristics: f = 5MHz, 50% duty cycle; t ≤ 6ns; Z = 50Ω.
r
0
Note 6: C includes probe and stray capacitance.
L
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MAX13442E/MAX13443E/
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±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Pin Description
PIN
NAME
FUNCTION
MAX13442E
MAX13444E
MAX13443E
Receiver Output. If the receiver is enabled and (V - V ) ≥ -50mV,
A
B
1
2
1
2
RO
RO = high; if (V - V ) ≤ -200mV, RO = low.
A
B
RE
Receiver Output Enable. Pull RE low to enable RO.
Driver Output Enable. Force DE high to enable driver. Pull DE low
to three-state the driver output. Drive RE high and pull DE low to
enter low-power shutdown mode.
3
4
—
—
DE
DI
Driver Input. A logic-low on DI forces the noninverting output
low and the inverting output high. A logic-high on DI forces the
noninverting output high and the inverting output low.
5
6
7
5
6
7
GND
A
Ground
Noninverting Receiver Input/Driver Output
Inverting Receiver Input/Driver Output
B
Positive Supply, V
= +4.75V to +5.25V. For normal operation,
CC
8
8
3
4
V
bypass V
protection, bypass V
to GND with a 0.1µF ceramic capacitor. For full ESD
CC
CC
to GND with 1µF ceramic capacitor.
CC
Driver Output Enable. Pull DE low to enable the outputs. Force DE
high to three-state the outputs. Drive RE and DE high to enter low-
power shutdown mode.
—
—
DE
J1708 Input. A logic-low on TXD forces outputs A and B to the
dominant state. A logic-high on TXD forces outputs A and B to the
recessive state.
TXD
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Fail-Safe RS-485/J1708 Transceivers
Function Tables
Table 1. MAX13442E/MAX13443E
(RS-485/RS-422)
Table 3. MAX13442E/MAX13443E
(RS-485/RS-422)
TRANSMITTING
RECEIVING
INPUTS
OUTPUTS
INPUTS
OUTPUTS
RE
DE
0
DI
X
0
A
B
RE
DE
X
(V - V )
RO
A
B
0
High-Z
High-Z
0
≥-0.05V
1
0
1
0
1
1
0
0
X
≤-0.2V
0
1
0
1
1
0
X
Open/shorted
1
0
X
0
Shutdown Shutdown
1
1
X
X
High-Z
Shutdown
1
1
0
1
1
0
1
0
1
1
1
X = Don’t care.
X = Don’t care.
Table 2. MAX13444E (J1708) Application
Table 4. MAX13444E (RS-485/RS-422)
TRANSMITTING
RECEIVING
INPUTS
OUTPUTS
CONDITIONS
INPUTS
OUTPUTS
TXD
DE
1
A
B
—
RE
DE
X
(V - V )
RO
A
B
0
1
0
1
High-Z
High-Z
0
High-Z
High-Z
1
—
0
≥-0.05V
1
1
—
0
X
≤-0.2V
0
1
0
Dominant state
Recessive state
0
X
Open/shorted
0
High-Z
High-Z
1
0
X
X
High-Z
Shutdown
1
1
X = Don’t care.
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MAX13442E/MAX13443E/
MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
outputs/receiver inputs of the MAX13442E/MAX13444E
withstand voltage faults up to ±80V (±60V for the
MAX13443E) with respect to ground without damage.
Protection is guaranteed regardless whether the device is
active, shut down, or without power.
Detailed Description
The MAX13442E/MAX13443E/MAX13444E fault-protect-
ed transceivers for RS-485/RS-422 and J1708 com-
munication contain one driver and one receiver. These
devices feature fail-safe circuitry, which guarantees a
logic-high receiver output when the receiver inputs are
open or shorted, or when they are connected to a termi-
nated transmission line with all drivers disabled (see the
True Fail-Safe section). All devices have a hot-swap input
structure that prevents disturbances on the differential
signal lines when a circuit board is plugged into a hot
backplane (see the Hot-Swap Capability section). The
MAX13442E/MAX13444E feature a reduced slew-rate
driver that minimizes EMI and reduces reflections caused
by improperly terminated cables, allowing error-free data
transmission up to 250kbps (see the Reduced EMI and
Reflections section). The MAX13443E driver is not slew-
rate limited, allowing transmit speeds up to 10Mbps.
True Fail-Safe
The MAX13442E/MAX13443E/MAX13444E use a -50mV
to -200mV differential input threshold to ensure true
fail-safe receiver inputs. This threshold guarantees the
receiver outputs a logic-high for shorted, open, or idle
data lines. The -50mV to -200mV threshold complies with
the ±200mV threshold EIA/TIA-485 standard.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures are
incorporated on all pins to protect against ESD encoun-
tered during handling and assembly. The MAX13442E/
MAX13443E/MAX13444E receiver inputs/driver outputs
(A, B) have extra protection against static electricity found
in normal operation. Maxim’s engineers have developed
state-of-the-art structures to protect these pins against
±15kV ESD without damage. After an ESD event, the
MAX13442E/MAX13443E/MAX13444E continue working
without latchup.
Driver
The driver accepts a single-ended, logic-level input (DI)
and transfers it to a differential, RS-485/RS-422 level
output (A and B). Deasserting the driver enable places
the driver outputs (A and B) into a high-impedance state.
Receiver
ESD protection can be tested in several ways. The receiv-
er inputs are characterized for protection to ±15kV using
the Human Body Model.
The receiver accepts a differential, RS-485/RS-422 level
input (A and B), and transfers it to a single-ended logic-
level output (RO). Deasserting the receiver enable places
the receiver inputs (A and B) into a high-impedance state
(see Table 1–Table 4).
ESD Test Conditions
ESD performance depends on a number of conditions.
Contact Maxim for a reliability report that documents test
setup, methodology, and results.
Low-Power Shutdown
The MAX13442E/MAX13443E/MAX13444E offer a low-
power shutdown mode. Force DE low and RE high to shut
down the MAX13442E/MAX13443E. Force DE and RE
high to shut down the MAX13444E. A time delay of 50ns
prevents the device from accidentally entering shutdown
due to logic skews when switching between transmit and
receive modes. Holding DE low and RE high for at least
800ns guarantees that the MAX13442E/MAX13443E
enter shutdown. In shutdown, the devices consume a
maximum 20μA supply current.
Human Body Model
Figure 9a shows the Human Body Model, and Figure 9b
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 device through a 1.5kΩ resistor.
Driver Output Protection
Two mechanisms prevent excessive output current and
power dissipation caused by faults or bus contention. The
first, a foldback current limit on the driver output stage,
provides immediate protection against short circuits over
the whole common-mode voltage range. The second, a
thermal shutdown circuit, forces the driver outputs into
a high-impedance state if the die temperature exceeds
+160°C. Normal operation resumes when the die temper-
ature cools to +140°C, resulting in a pulsed output during
continuous short-circuit conditions.
±80V Fault Protection
The driver outputs/receiver inputs of RS-485 devices in
industrial network applications often experience voltage
faults resulting from shorts to the power grid that exceed
the -7V to +12V range specified in the EIA/TIA-485 stan-
dard. In these applications, ordinary RS-485 devices
(typical absolute maximum -8V to +12.5V) require costly
external protection devices. To reduce system complexity
and eliminate this need for external protection, the driver
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±15kV ESD-Protected, ±80V Fault-Protected,
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Hot-Swap Input Circuitry
Hot-Swap Capability
At the driver-enable input (DE), there are two NMOS
Hot-Swap Inputs
devices, M1 and M2 (Figure 10). When V
ramps from
CC
Inserting circuit boards into a hot, or powered, backplane
may cause voltage transients on DE, RE, and receiver
inputs A and B that can lead to data errors. For example,
upon initial circuit board insertion, the processor under-
goes a power-up sequence. During this period, the high-
impedance state of the output drivers makes them unable
to drive the MAX13442E/MAX13443E/MAX13444E
enable inputs to a defined logic level. Meanwhile, leakage
currents of up to 10μA from the high-impedance output, or
zero, an internal 15μs timer turns on M2 and sets the SR
latch, which also turns on M1. Transistors M2, a 2mA cur-
rent sink, and M1, a 100μA current sink, pull DE to GND
through a 5.6kΩ resistor. M2 pulls DE to the disabled
state against an external parasitic capacitance up to
100pF that may drive DE high. After 15μs, the timer deac-
tivates M2 while M1 remains on, holding DE low against
three-state leakage currents that may drive DE high. M1
remains on until an external current source overcomes
the required input current. At this time, the SR latch resets
M1 and turns off. When M1 turns off, DE reverts to a stan-
capacitively coupled noise from V
or GND, could cause
CC
an input to drift to an incorrect logic state. To prevent such
a condition from occurring, the MAX13442E/MAX13443E/
MAX13444E feature hot-swap input circuitry on DE, and
RE to guard against unwanted driver activation during
hot-swap situations. The MAX13444E has hot-swap input
dard, high-impedance CMOS input. Whenever V
below 1V, the input is reset.
drops
CC
A complementary circuit for RE uses two PMOS devices
to pull RE to V
.
circuitry only on RE. When V
rises, an internal pulldown
CC
CC
(or pullup for RE) circuit holds DE low for at least 10μs,
and until the current into DE exceeds 200μA. After the
initial power-up sequence, the pulldown circuit becomes
transparent, resetting the hot-swap tolerable input.
R
R
D
C
1.5kΩ
1MΩ
DISCHARGE
RESISTANCE
CHARGE-CURRENT-
LIMIT RESISTOR
V
CC
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
100pF
STORAGE
CAPACITOR
s
15µs
TIMER
SOURCE
TIMER
Figure 9a. Human Body ESD Test Model
I
P
100%
90%
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
r
5.6kΩ
DE
(HOT SWAP)
AMPERES
2mA
100µA
36.8%
M1
M2
10%
0
TIME
0
t
RL
t
DL
CURRENT WAVEFORM
Figure 9b. Human Body Model Current Waveform
Figure 10. Simplified Structure of the Driver Enable Pin (DE)
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MAX13442E/MAX13443E/
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±15kV ESD-Protected, ±80V Fault-Protected,
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In general, a transmitter’s rise time relates directly to the
length of an unterminated stub that can be driven with
only minor waveform reflections. The following equation
Applications Information
128 Transceivers on the Bus
The MAX13442E/MAX13443E/MAX13444E transceivers
1/4-unit-load receiver input impedance (48kΩ) allows up
to 128 transceivers connected in parallel on one commu-
nication line. Connect any combination of these devices,
and/or other RS-485 devices, for a maximum of 32-unit
loads to the line.
expresses this relationship conservatively:
length = t /(10 x 1.5ns/ft)
RISE
where t
is the transmitter’s rise time.
RISE
For example, the MAX13442E’s rise time is typically
800ns, which results in excellent waveforms with a stub
length up to 53ft. A system can work well with longer
unterminated stubs, even with severe reflections, if the
waveform settles out before the UART samples them.
Reduced EMI and Reflections
The MAX13442E/MAX13444E are slew-rate limited, mini-
mizing EMI and reducing reflections caused by improp-
erly terminated cables. Figure 11 shows the driver output
waveform and its Fourier analysis of a 125kHz signal
transmitted by a MAX13443E. High-frequency harmonic
components with large amplitudes are evident.
RS-485 Applications
The MAX13442E/MAX13443E/MAX13444E transceivers
provide bidirectional data communications on multipoint
bus transmission lines. Figure 13 shows a typical net-
work application circuit. The RS-485 standard covers line
lengths up to 4000ft. To minimize reflections and reduce
data errors, terminate the signal line at both ends in its
characteristic impedance, and keep stub lengths off the
main line as short as possible.
Figure 12 shows the same signal displayed for the
MAX13442E transmitting under the same conditions.
Figure 12’s high-frequency harmonic components are
much lower in amplitude, compared with Figure 11’s, and
the potential for EMI is significantly reduced.
20dB/div
2V/div
20dB/div
2V/div
0
500kHz/div
5.00MHz
0
500kHz/div
5.00MHz
Figure 11. Driver Output Waveform and FFT Plot of the
MAX13443E Transmitting a 125kHz Signal
Figure 12. Driver Output Waveform and FFT Plot of the
MAX13442E Transmitting a 125kHz Signal
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±15kV ESD-Protected, ±80V Fault-Protected,
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idle in this configuration, all receivers output logic-high
because of the pullup resistor on A and pulldown resistor
J1708 Applications
The MAX13444E is designed for J1708 applications. To
configure the MAX13444E, connect DE and RE to GND.
Connect the signal to be transmitted to TXD. Terminate
the bus with the load circuit as shown in Figure 14. The
drivers used by SAE J1708 are used in a dominant-mode
application. DE is active low; a high input on DE places
the outputs in high impedance. When the driver is dis-
abled (TXD high or DE high), the bus is pulled high by
external bias resistors R1 and R2. Therefore, a logic-level
high is encoded as recessive. When all transceivers are
on B. R1 and R2 provide the bias for the recessive state.
C1 and C2 combine to form a lowpass filter, effective for
reducing FM interference. R2, C1, R4, and C2 combine
to form a 1.6MHz lowpass filter, effective for reducing AM
interference. Because the bus is unterminated, at high
frequencies, R3 and R4 perform a pseudotermination.
This makes the implementation more flexible, as no spe-
cific termination nodes are required at the ends of the bus.
120Ω
120Ω
DE
B
B
DI
D
D
DI
DE
A
A
B
A
B
A
RO
RE
RO
RE
R
R
R
R
D
D
MAX13442E
MAX13443E
DI
DE RO
DI
DE RO
RE
RE
Figure 13. MAX13442E/MAX13443E Typical RS-485 Network
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MAX13442E/MAX13443E/
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±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Chip Information
PROCESS: BiCMOS
DE
R1
4.7kΩ
Package Information
R3
47Ω
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.
T
X
D
TXD
B
A
C1
2.2nF
J1708 BUS
C2
2.2nF
MAX13444E
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
R4
47Ω
R2
4.7kΩ
R
X
R
RO
8 SO
S8+4
21-0041
90-0096
V
CC
RE
Figure 14. J1708 Application Circuit (See Tables 2 and 4)
Pin Configurations and Typical Operating Circuits (continued)
DE
D
+
+
MAX13444E
V
1
2
3
8
7
6
RO
RE
DE
CC
R
R
V
RO
1
2
3
4
8
7
6
5
CC
TXD
RO
B
B
A
B
RE
DE
R
T
R
T
A
A
GND
R
4
TXD
GND
D
5
D
TXD
RE
SO
SO
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MAX13442E/MAX13443E/
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±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
Revision History
REVISION REVISION
PAGES
DESCRIPTION
CHANGED
NUMBER
DATE
0
10/05
Initial release
—
Corrected the part numbers in the conditions for ΔV
in the DC Electrical
OC
1
3/06
Characteristics table; corrected the A, B current units from mA to FA for the A, B Current
2, 7
vs. A, B Voltage (to Ground) graphs in the Typical Operating Characteristics section
Added lead(Pb)-free parts to the Ordering Information table; added the soldering
temperature to the Absolute Maximum Ratings section; updated Table 2 outputs
2
3
11/10
3/11
1, 2, 12
1, 2
Added an automotive qualified part to the Ordering Information; added the Package
Thermal Characteristics section
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
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.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2011 Maxim Integrated Products, Inc.
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