19-2756; Rev 1; 4/03
±80V Fault-Protected, Fail-Safe,
1/4-Unit Load, +3.3V RS-485 Transceiver
General Description
The MAX3430 fault-protected RS-485 transceiver features
±80V
protection from overvoltage signal faults on commu-
nication bus lines. Each device contains one driver and
one receiver, and the output pins can withstand faults,
with respect to ground, of up to ±80V. Even if the faults
occur when the transceiver is active, shut down, or pow-
ered off, the device will not be damaged. The MAX3430
operates from a 3.3V supply and features a slew-rate-lim-
ited driver that minimizes EMI and reduces reflections
caused by improperly terminated cables, allowing error-
free data transmission at data rates up to 250kbps. The
MAX3430 has a 1/4-unit-load receiver input impedance
allowing up to 128 transceivers on a single bus and fea-
tures fail-safe circuitry, which guarantees a logic-high
receiver output when the receiver inputs are open.
Hot-swap circuitry eliminates false transitions on the
data cable during circuit initialization or connection to a
live backplane. Short-circuit current limiting and ther-
mal-shutdown circuitry protect the driver against exces-
sive power dissipation.
The MAX3430 is available in 8-pin SO and 8-pin PDIP
packages, and is specified over commercial and indus-
trial temperature ranges.
o
±80V Fault Protection
o
±12kV ESD Protection
o
+3.3V Operation
o
Internal Slew-Rate Limiting
o
250kbps Data Rate
o
Allows Up to 128 Transceivers on the Bus
o
-7V to +12V Common-Mode Input Voltage Range
o
True Fail-Safe Inputs
o
Hot-Swap Input Structure on DE
o
Available in 8-Pin SO and PDIP Packages
Features
MAX3430
Ordering Information
PART
MAX3430CPA
MAX3430CSA
MAX3430EPA
MAX3430ESA
TEMP RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
Applications
RS-422/RS-485 Communications
Lighting Systems
Industrial-Control Local Area Networks
Profibus Applications
Multimaster RS-485 Networks
Pin Configuration and Typical Operating Circuit
TOP VIEW
V
CC
0.1µF
DE
RO
RE
1
2
R
8
7
6
V
CC
B
A
GND
RO
1
R
8
7 B
6
Rt
A
GND
MAX3430
D
B
Rt
A
R
RE
RO
DI
DE 3
DI
4
D
5
RE 2
3
DE
4
DI
D
5
DIP/SO
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
±80V Fault-Protected, Fail-Safe,
1/4-Unit Load, +3.3V RS-485 Transceiver
MAX3430
ABSOLUTE MAXIMUM RATINGS
(All voltages are referenced to GND.)
V
CC
........................................................................................+5V
RE,
DE, DI...................................................-0.3V to (V
CC
+ 0.3V)
Driver Output Voltage (A, B) (Note 1) ..................................±80V
Receiver Input Voltage (A, B) (Note 1) ................................±80V
RO ..............................................................-0.3V to (V
CC
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ...727mW
Operating Temperature Ranges
MAX3430C_ _ .....................................................0°C to +70°C
MAX3430E_ _ ..................................................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1:
A, B must be terminated with 54Ω or 100Ω to guarantee ±80V fault protection.
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
CC
= +3.3V ±10%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.)
PARAMETER
DRIVER
Differential Driver Output
Change in Magnitude of
Differential Output Voltage
Driver Common-Mode Output
Voltage
Change in Magnitude of
Common-Mode Voltage
DRIVER LOGIC
Driver Input High Voltage
Driver Input Low Voltage
Driver Input Current
Driver Short-Circuit Output
Current
Driver Short-Circuit Foldback
Output Current
RECEIVER
DE = GND,
RE
= GND, V
IN
= +12V
Input Current (A, B)
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
I
A, B
DE = GND,
RE
= GND, V
IN
= -7V
V
IN
= -80V to +80V
V
TH
∆V
TH
-7V
≤
V
CM
≤
12V
V
A
+ V
B
= 0
-6
-200
25
250
-200
+6
-50
µA
mA
mV
mV
V
IH
V
IL
I
IN
I
OSD
I
OSDF
DI
DI
DI
0
≤
V
OUT
≤
12V (Note 3)
-7V
≤
V
OUT
≤
V
CC
(Note 3)
(V
CC
- 1V)
≤
V
OUT
≤
12V (Note 3)
-7V
≤
V
OUT
≤
1V (Note 3)
-250
+10
-10
2.0
0.8
±1
+250
V
V
µA
mA
mA
V
OD
∆V
OD
V
OC
∆V
OC
Figure 1, R
L
= 100Ω
Figure 1, R
L
= 54Ω
Figure 1, R
L
= 100Ω or 54Ω (Note 2)
Figure 1, R
L
= 100Ω or 54Ω
Figure 1, R
L
= 100Ω or 54Ω (Note 2)
V
CC
/ 2
2.0
1.5
V
CC
V
CC
0.2
3
0.2
V
V
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
±80V Fault-Protected, Fail-Safe,
1/4-Unit Load, +3.3V RS-485 Transceiver
DC ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.3V ±10%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.)
PARAMETER
RECEIVER LOGIC
RO Output High Voltage
RO Output Low Voltage
Three-State Output Current at
Receiver
Receiver Input Resistance
Receiver Output Short-Circuit
Current
CONTROL
Control Input High Voltage
Control Input Low Voltage
Input Current DE Current Latch
During First DE Rising Edge
Input Current
RE
Current Latch
During First
RE
Rising Edge
V
CIH
V
CIL
DE,
RE
DE,
RE
80
80
2.0
0.8
V
V
µA
µA
V
OH
V
OL
I
OZR
R
IN
I
OSR
I
O
= -1.6mA
I
O
= 1mA
0
≤
V
O
≤
V
CC
-7V
≤
V
CM
≤
12V
0
≤
V
RO
≤
V
CC
48
±95
V
CC
-
0.6
0.4
±
1
V
V
µA
kΩ
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX3430
PROTECTION SPECIFICATIONS
(V
CC
= +3.3V
±10%,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.)
PARAMETER
ESD Protection
SUPPLY CURRENT
No load,
RE
= 0, DE = V
CC
, DI = 0 or V
CC
Supply Current
Supply Current in Shutdown
Mode
I
CC
No load,
RE
= V
CC
, DE = V
CC,
DI = 0 or V
CC
RE
= V
CC
, DE = 0
3.5
3.0
10
8
200
mA
SYMBOL
A, B
CONDITIONS
Human Body Model
MIN
TYP
±12
MAX
UNITS
kV
I
SHDN
µA
_______________________________________________________________________________________
3
±80V Fault-Protected, Fail-Safe,
1/4-Unit Load, +3.3V RS-485 Transceiver
MAX3430
DRIVER SWITCHING CHARACTERISTICS
(V
CC
= +3.3V
±10%,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.)
PARAMETER
Driver Propagation Delay
Driver Differential Output Rise or
Fall Time
Differential Driver Output Skew,
|t
DPLH
- t
DPHL
|
Maximum Data Rate
Driver Enable to Output Low
Driver Disable Time from Output
Low
Driver Output Enable Time from
Shutdown
Driver Enable to Output High
Driver Disable Time from Output
High
Driver Output Enable Time from
Shutdown
Driver Time to Shutdown
t
DZL
t
DLZ
Figure 4, C
L
= 50pF
Figure 4, C
L
= 50pF
SYMBOL
t
DPLH
t
DPHL
t
DR,
t
DF
t
DSKEW
CONDITIONS
Figures 2 and 3, R
L
= 54Ω, C
L
= 50pF
Figures 2 and 3, R
L
= 54Ω, C
L
= 50pF
Figures 2 and 3, R
L
= 54Ω, C
L
= 50pF
250
5200
1000
8000
5200
1000
8000
1000
250
150
MIN
TYP
700
700
MAX
1500
1500
1200
200
UNITS
ns
ns
ns
kbps
ns
ns
ns
ns
ns
ns
ns
t
DZL(SHDN)
Figure 4, C
L
= 50pF
t
DZH
t
DHZ
Figure 5, C
L
= 50pF
Figure 5, C
L
= 50pF
t
DZH(SHDN)
Figure 5, C
L
= 50pF
t
SHDN
RECEIVER SWITCHING CHARACTERISTICS
(V
CC
= +3.3V
±10%,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.)
PARAMETER
Receiver Propagation Delay
Receiver Output Skew,
|t
RPLH
- t
RPHL
|
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time form High
Receiver Output Enable Time
from Shutdown
Receiver Time to Shutdown
SYMBOL
t
RPLH
t
RPHL
t
SKEW
t
RZL
t
RZH
t
RLZ
t
RHZ
CONDITIONS
Figure 6, C
L
= 20pF, V
ID
= 2V, V
CM
= 0
Figure 6, C
L
= 20pF
Figure 7, R = 1kΩ, C
L
= 20pF
Figure 7, R = 1kΩ, C
L
= 20pF
Figure 7, R = 1kΩ, C
L
= 20pF
Figure 7, R = 1kΩ , C
L
= 20pF
MIN
TYP
MAX
120
120
40
80
80
80
80
5000
1000
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
t
RZH(SHND)
,
Figure 7, R = 1kΩ, C
L
= 20pF
t
RZL(SHND)
t
SHDN
Note 2:
∆V
OD
and
∆V
OC
are the changes in V
OD
and V
OC
, respectively, when the DI input changes state.
Note 3:
The short-circuit output current applies to peak current just prior to foldback current limiting; the short-circuit foldback output
current applies during current limiting to allow a recovery from bus contention.
4
_______________________________________________________________________________________
±80V Fault-Protected, Fail-Safe,
1/4-Unit Load, +3.3V RS-485 Transceiver
Typical Operating Characteristics
(V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
MAX3430
SUPPLY CURRENT
vs. TEMPERATURE
MAX3430 toc01
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX3430 toc02
OUTPUT CURRENT
vs. RECEIVER OUTPUT LOW VOLTAGE
MAX3430 toc03
5
RE = 0
DE = V
CC
4
SUPPLY CURRENT (mA)
200
175
SHUTDOWN CURRENT (µA)
150
125
100
75
50
25
20
16
OUTPUT CURRENT (mA)
3
12
2
8
1
4
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT
vs. RECEIVER OUTPUT HIGH VOLTAGE
MAX3430 toc04
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
MAX3430 toc05
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
I
O
= +1mA
MAX3430 toc06
18
15
OUTPUT CURRENT (mA)
12
9
6
3
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.30
I
O
= -1.6mA
3.25
OUTPUT HIGH VOLTAGE (V)
3.20
3.15
3.10
3.05
3.00
0.5
OUTPUT LOW VOLTAGE (V)
-40
-20
0
20
40
60
80
0.4
0.3
0.2
0.1
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
3.5
OUTPUT HIGH VOLTAGE (V)
DRIVER OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX3430 toc07
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
MAX3430 toc08
A, B CURRENT
vs. A, B VOLTAGE (TO GROUND)
MAX3430 toc09
120
100
OUTPUT CURRENT (mA)
80
60
40
20
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
DIFFERENTIAL OUTPUT VOLTAGE (V)
3.0
2.5
2.0
1.5
1.0
0.5
0
R
L
= 100Ω
3
2
A, B CURRENT (mA)
1
0
-1
-2
RE = DE = GND
-3
R
L
= 54Ω
3.5
-40
-20
0
20
40
60
80
-80
-60
-40
-20
0
20
40
60
80
DIFFERENTIAL OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
A, B VOLTAGE (V)
_______________________________________________________________________________________
5
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