19-4098; Rev 0; 5/08
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
General Description
The MAX13448E full-duplex RS-485 transceiver fea-
tures inputs and outputs fault protected up to ±80V
(with respect to ground). The device operates from a
+3.0V to +5.5V supply and features true fail-safe cir-
cuitry, guaranteeing a logic-high receiver output when
the receiver inputs are open or shorted. This enables all
receiver outputs on a terminated bus to output logic-
high when all transmitters are disabled.
The MAX13448E features a slew-rate limited driver that
minimizes EMI and reduces reflections caused by
improperly terminated cables, allowing error-free data
transmission at data rates up to 500kbps with a +5V
supply, and 250kbps with a +3.3V supply.
The MAX13448E includes a hot-swap capability to elimi-
nate false transitions on the bus during power-up or hot
insertion. The driver and receiver feature active-high and
active-low enables, respectively, that can be connected
together externally to serve as a direction control.
The MAX13448E features an 1/8-unit load receiver input
impedance, allowing up to 256 transceivers on the bus.
All driver outputs are protected to ±8kV ESD using the
Human Body Model. The MAX13448E is available in a
14-pin SO package and operates over the extended
-40°C to +85°C temperature range.
o
True Fail-Safe Receiver
o
Hot-Swap Input Structure on DE
o
ESD Protection on the RS-485 I/O Ports
±8kV Human Body Model
o
Slew-Rate Limiting Facilitates Error-Free Data
Transmission
o
1/8-Unit Load Allows Up to 256 Transceivers on
the Bus
o
-7V to +12V Common-Mode Input Voltage Range
o
+3.0V to +5.5V Operating Supply Voltage
o
Available in 14-Pin SO Package
Features
o
±80V Fault Protection on the RS-485 I/O Ports
MAX13448E
Ordering Information
PART
MAX13448EESD+
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
14 SO
+Denotes
a lead-free package.
Applications
Industrial Control Systems
HVAC Control systems
Utility Meters
Motor Driver Control Systems
Pin Configuration appears at end of data sheet.
Functional Diagram
+
R
N.C. 1
RO 2
RE 3
DE 4
DI 5
14 V
CC
13 N.C.
12 A
11 B
10 Z
D
MAX13448E
DE
4 14
V
CC
1μF
9
Y
R
t
Z
V
CC
RE
DI
5
D
10
R
RO
12
RO
2
1, 8,
13
3
RE
6, 7
GND
R
11
A
R
t
B
D
DI
GND 6
GND 7
9 Y
N.C.
8 N.C.
GND
DE
SO
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
MAX13448E
ABSOLUTE MAXIMUM RATINGS
(All voltages reference to GND.)
Supply Voltage (V
CC
).............................................................+6V
Control Input Voltage (RE, DE)...................-0.3V to (V
CC
+ 0.3V)
Driver Input Voltage (DI).............................-0.3V to (V
CC
+ 0.3V)
Receiver Input Voltage (A, B (Note 1)) ................................±80V
Driver Output Voltage (Y, Z (Note 1)) ..................................±80V
Receiver Output Voltage (RO)....................-0.3V to (V
CC
+ 0.3V)
Short-Circuit Duration (RO, A, B) ...............................Continuous
Continuous Power Dissipation (T
A
= +70°C)
14-Pin SO (derate 8.3mW/°C above +70°C)................667mW
Operating Temperature Range ...........................-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:
If the RS-485 transmission lines are unterminated and a short to a voltage V
SHT
occurs at a remote point on the line, an active
local driver (with DI switching) may see higher voltage than V
SHT
due to inductive kickback at the driver. Terminating the line
with a resistor equal to its characteristic impedance minimizes this kickback effect.
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.
ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0 to +5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
V
CC
Supply Voltage Range
Supply Current
Supply Current in Shutdown
Mode
Supply Current with Output
Shorted to ±60V
DRIVER
Differential Driver Output
Change in Magnitude of
Differential Output Voltage
Driver Common-Mode Output
Voltage
Change in Magnitude of
Common-Mode Voltage
Driver Short-Circuit Output
Current
Driver Short-Circuit Foldback
Output Current
Driver-Limit Short-Circuit
Foldback Output Current
Driver Input High Voltage
Driver Input Low Voltage
Driver Input Current
V
OD
ΔV
OD
V
OC
ΔV
OC
I
OSD
I
OSDF
I
OSDL
V
DIH
V
DIL
I
DIN
-1
R
L
= 100Ω, Figure 1
R
L
= 54Ω, Figure 1
R
L
= 100Ω or 54Ω, Figure 1 (Note 4)
RL = 100Ω or 54Ω, Figure 1
RL = 100Ω or 54Ω, Figure 1 (Note 4)
DI = low, 0V
≤
V
Y
or V
Z
≤
+12V
DI = high, -7V
≤
V
Y
or V
Z
≤
V
CC
(Note 5)
DI = low, (V
CC
- 1V)
≤
V
Y
or V
Z
≤
+12V
DI = high, -7V
≤
V
Y
or V
Z
≤
+1V
V
Y
or V
Z
≥
+ 22V, R
L
= 100Ω
V
Y
or V
Z
≤
-13V, R
L
= 100Ω
-6
2
0.8
+1
-250
+10
-10
+6
-0.2
2
1.5
-0.2
V
CC
/2
V
CC
V
CC
0.2
3
+0.2
+250
V
V
V
V
mA
mA
mA
V
V
µA
SYMBOL
V
CC
I
Q
I
SHDN
I
SHRT
No load, DE, DI,
RE
= 0V or V
CC
, V
CC
= 3.3V
No load, DE, DI,
RE
= 0V or V
CC
, V
CC
= 5V
DE = GND,
RE
= V
CC
, V
CC
= 3.3V
DE = GND,
RE
= V
CC
, V
CC
= 5V
DE = GND,
RE
= GND, short to +60V
DE = GND,
RE
= GND, short to -60V
CONDITION
MIN
3.0
TYP
MAX
5.5
15
15
100
100
15
15
UNITS
V
mA
µA
mA
2
_______________________________________________________________________________________
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0 to +5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
RECEIVER
V
A
, V
B
= +12V
Input Current
I
A
,
B
V
A
, V
B
= -7V
V
A
, V
B
= ±80V
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
Output High Voltage
Output Low Voltage
Three-State Output Current at
Receiver
Receiver Output Short-Circuit
Current
ESD PROTECTION
All Pins
ESD Protection Level
(A and B, Y and Z)
CONTROL
Control Input High Voltage
Control Input Low Voltage
Input Current Latch During First
Rising Edge
PROTECTION SPECIFICATIONS
Overvoltage Protection
A, B, Y, Z
-80
+80
V
V
CIH
V
CIL
I
IN
DE,
RE
DE,
RE
DE,
RE
80
2
0.8
V
V
µA
Human Body Model
Human Body Model
±2
±8
kV
kV
V
TH
ΔV
TH
V
OH
V
OL
I
OZR
I
OSR
I
OH
= -1.6mA
I
OL
= 1mA
0
≤
V
A
, V
B
≤
V
CC
0
≤
V
RO
≤
V
CC
-1
-95
V
CC
-
0.6
0.4
+1
+95
-7V
≤
V
CM
≤
+12V
V
CC
= GND or
V
CC
= +3.0V to +5.5V
-100
-6
-200
25
+6
-50
+125
µA
µA
mA
mV
mV
V
V
µA
mA
SYMBOL
CONDITION
MIN
TYP
MAX
UNITS
MAX13448E
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
Driver Differential Propagation
Delay
Driver Differential Output
Transition Time
Differential Driver Output Skew
Maximum Data Rate
Driver Enable Time to Output High
t
DPLH
,
t
DPHL
t
LH
, t
HL
t
DSKEW
f
MAX
t
DZH
R
L
= 500Ω, C
L
= 50pF, Figure 4
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, t
DSKEW
= [t
DPLH
-
t
DPHL
], Figures 2 and 3
250
2000
250
150
700
1500
1200
200
ns
ns
ns
kbps
ns
SYMBOL
CONDITION
MIN
TYP
MAX
UNITS
_______________________________________________________________________________________
3
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
MAX13448E
SWITCHING CHARACTERISTICS (V
CC
= +3.3V ±10%) (continued)
(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 Disable Time from
Output High
Driver Enable Time from
Shutdown to Output High
Driver Enable Time to Output Low
Driver Disable Time from
Output Low
Driver Enable Time from
Shutdown to Output Low
Driver Time to Shutdown
RECEIVER
Receiver Propagation Delay
Receiver Output Skew
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
RPLH
,
t
RPHL
t
RSKEW
t
RZH
t
RHZ
t
RWAKE
t
RZL
t
RLZ
t
SHDN
C
L
= 20pF, V
ID
= 2V, V
CM
= 0V,
Figure 6
C
L
= 20pF, t
RSKEW
= [t
RPLH
- t
RPHL
],
Figure 6
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 500Ω, C
L
= 50pF
2000
200
1000
150
5
1000
150
200
ns
ns
ns
ns
µs
ns
ns
ns
SYMBOL
t
DHZ
CONDITION
R
L
= 500Ω, C
L
= 50pF, Figure 4
MIN
TYP
MAX
1000
8
1500
2000
8
12
UNITS
ns
µs
ns
ns
µs
µs
t
DZH(SHDN)
R
L
= 500Ω, C
L
= 50pF, Figure 4
t
DZL
t
DLZ
R
L
= 500Ω, C
L
= 50pF, Figure 5
R
L
= 500Ω, C
L
= 50pF, Figure 5
t
DZL(SHDN)
R
L
= 500Ω, C
L
= 50pF, Figure 5
t
SHDN
R
L
= 500Ω, C
L
= 50pF
SWITCHING CHARACTERISTICS (V
CC
= +5V ±10%)
(T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25°C.)
PARAMETER
DRIVER
Driver Differential Propagation
Delay
Driver Differential Output
Transition Time
Differential Driver Output Skew
Maximum Data Rate
t
DPLH
,
t
DPHL
t
LH
, t
HL
t
DSKEW
f
MAX
R
L
= 54Ω, C
L
= 50pF, Figure 3
R
L
= 54Ω, C
L
= 50pF, Figure 3
R
L
= 54Ω, C
L
= 50pF, t
DSKEW
= [t
DPLH
-
t
DPHL
], Figure 3
500
100
800
1200
200
ns
ns
ns
kbps
SYMBOL
CONDITION
MIN
TYP
MAX
UNITS
4
_______________________________________________________________________________________
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
SWITCHING CHARACTERISTICS (V
CC
= +5V ±10%) (continued)
(T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25°C.)
PARAMETER
Driver Enable Time to Output High
Driver Disable Time from
Output High
Driver Enable Time from
Shutdown to Output High
Driver Enable Time to Output Low
Driver Disable Time from
Output Low
Driver Enable Time from
Shutdown to Output Low
Driver Time to Shutdown
RECEIVER
Receiver Propagation Delay
Receiver Output Skew
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
RPLH
,
t
RPHL
t
RSKEW
t
RZH
t
RHZ
t
RWAKE
t
RZL
t
RLZ
t
SHDN
C
L
= 20pF, V
ID
= 2V, V
CM
= 0V,
Figure 6
C
L
= 20pF, t
RSKEW
= [t
RPLH
- t
RPHL
],
Figure 6
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 1kΩ, C
L
= 20pF, Figure 7
R
L
= 500Ω, C
L
= 50pF
2000
200
1000
150
8
1000
150
150
ns
ns
ns
ns
µs
ns
ns
ns
SYMBOL
t
DZH
t
DHZ
CONDITION
R
L
= 500Ω, C
L
= 50pF, Figure 4
R
L
= 500Ω, C
L
= 50pF, Figure 4
MIN
TYP
MAX
1500
1000
8
1000
2
8
12
UNITS
ns
ns
µs
ns
µs
µs
µs
MAX13448E
t
DZH(SHDN)
R
L
= 500Ω, C
L
= 50pF, Figure 4
t
DZL
t
DLZ
R
L
= 500Ω, C
L
= 50pF, Figure 5
R
L
= 500Ω, C
L
= 50pF, Figure 5
t
DZL(SHDN)
R
L
= 500Ω, C
L
= 50pF, Figure 5
t
SHDN
R
L
= 500Ω, C
L
= 50pF
Note 2:
Parameters are 100% production tested at T
A
= +25°C, unless otherwise noted. Limits over temperature are guaranteed by
design.
Note 3:
All currents into the device are positive. All currents out of the device are negative. All voltages are referenced to device
ground, unless otherwise noted.
Note 4:
ΔV
OD
and
ΔV
OC
are the changes in V
OD
and V
OC
, respectively, when the DI input changes state.
Note 5:
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 recover from bus contention.
_______________________________________________________________________________________
5
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