General Description
The MAX13448E full-duplex RS-485 transceiver features 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 circuitry, 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 logichigh 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 eliminate 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.
Applications
Industrial Control Systems
HVAC Control systems
Utility Meters
Motor Driver Control Systems
Features
o ±80V Fault Protection on the RS-485 I/O Ports
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
MAX13448E
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
19-4098; Rev 0; 5/08
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.
Pin Configuration appears at end of data sheet.
+
Denotes a lead-free package.
R
t
RE
RO
Y
Z
DI
9
10
A
B
R
t
12
11
6, 73
R
D
R
DI
D
DE
RE
RO
N.C.
R
D
DE
GND
GND
V
CC
1μF
141
SO
+
V
CC
N.C.
132 N.C.RO
123ARE
114BDE
105ZDI
96YGND
87 N.C.GND
1, 8,
13
2
5
414
V
CC
MAX13448E
Functional Diagram
PART TEMP RANGE PIN-PACKAGE
MAX13448EESD+ -40°C to +85°C 14 SO
MAX13448E
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= +3.0 to +5.5V, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Notes 2, 3)
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.
(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.
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS
VCC Supply Voltage Range V
Supply Current I
Supply Current in Shutdown
Mode
Supply Current with Output
Shorted to ±60V
DRIVER
Differential Driver Output V
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 V
Driver Input Low Voltage V
Driver Input Current I
CC
I
SHDN
I
SHRT
OD
ΔV
V
OC
ΔV
I
OSD
I
OSDF
I
OSDL
DIH
DIL
DIN
N o l oad , D E , D I, RE = 0V or V
Q
No load, DE, DI, RE = 0V or VCC, VCC = 5V 15
DE = GND, RE = VCC, VCC = 3.3V 100
DE = GND, RE = VCC, VCC = 5V 100
DE = GND, RE = GND, short to +60V 15
DE = GND, RE = GND, short to -60V 15
RL = 100Ω, Figure 1 2 V
RL = 54Ω, Figure 1 1.5 V
RL = 100Ω or 54Ω, Figure 1 (Note 4) -0.2 0.2 V
OD
RL = 100Ω or 54Ω, Figure 1 VCC/2 3 V
RL = 100Ω or 54Ω, Figure 1 (Note 4) -0.2 +0.2 V
OC
DI = low, 0V ≤ VY or VZ ≤ +12V +250
DI = high, -7V ≤ VY or VZ ≤ VCC (Note 5) -250
DI = low, (VCC - 1V) ≤ VY or VZ ≤ +12V +10
DI = high, -7V ≤ VY or VZ ≤ +1V -10
VY or VZ ≥ + 22V, RL = 100Ω +6
VY or VZ ≤ -13V, RL = 100Ω -6
2V
0.8 V
-1 +1 µA
, V
= 3.3V 15
C C
C C
3.0 5.5 V
CC
CC
mA
µA
mA
V
mA
mA
mA
MAX13448E
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.0 to +5.5V, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Notes 2, 3)
SWITCHING CHARACTERISTICS (VCC= +3.3V ±10%)
(TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.)
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS
RECEIVER
Input Current IA,
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis ΔV
Output High Voltage V
Output Low Voltage V
Three-State Output Current at
Receiver
Receiver Output Short-Circuit
Current
ESD PROTECTION
All Pins Human Body Model ±2 kV
ESD Protection Level
(A and B, Y and Z)
CONTROL
Control Input High Voltage V
Control Input Low Voltage V
Input Current Latch During First
Rising Edge
PROTECTION SPECIFICATIONS
Overvoltage Protection A, B, Y, Z -80 +80 V
V
= GND or
CC
= +3.0V to +5.5V
V
CC
25 mV
V
-
CC
0.6
-1 +1 µA
-95 +95 mA
V
I
OZR
I
OSR
I
TH
TH
OH
OL
CIH
CIL
IN
VA, VB = +12V
B
VA, VB = -7V -100 µA
VA, VB = ±80V -6 +6 mA
-7V ≤ V
IOH = -1.6mA
IOL = 1mA 0.4 V
0 ≤ VA, VB ≤ V
0 ≤ VRO ≤ V
Human Body Model ±8 kV
DE, RE 2V
DE, RE 0.8 V
DE, RE 80 µA
≤ +12V -200 -50 mV
CM
CC
CC
+125 µA
V
DRIVER
Driver Differential Propagation
Delay
Driver Differential Output
Transition Time
Differential Driver Output Skew t
Maximum Data Rate f
D r i ver E nab l e Ti m e to Outp ut H i g ht
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS
t
,
DPLH
t
DPHL
, t
t
LH
DSKEW
MAX
DZH
RL = 54Ω, CL = 50pF, Figures 2 and 3 700 1500 ns
HLRL
= 54Ω, CL = 50pF, Figures 2 and 3 250 1200 ns
RL = 54Ω, CL = 50pF, t
], Figures 2 and 3
t
DPHL
RL = 500Ω, CL = 50pF, Figure 4 2000 ns
DSKEW
= [t
DPLH
-
250 kbps
150 200 ns
MAX13448E
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
4 _______________________________________________________________________________________
SWITCHING CHARACTERISTICS (VCC= +3.3V ±10%) (continued)
(TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.)
SWITCHING CHARACTERISTICS (VCC= +5V ±10%)
(TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +5V and TA= +25°C.)
)
)
Driver Disable Time from
Output High
Driver Enable Time from
Shutdown to Output High
D r i ver E nab l e Ti m e to Outp ut Low t
Driver Disable Time from
Output Low
Driver Enable Time from
Shutdown to Output Low
Driver Time to Shutdown t
RECEIVER
Receiver Propagation Delay
Receiver Output Skew t
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
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS
t
DHZ
t
DZH(SHDN
DZL
t
DLZ
t
DZL(SHDN
SHDN
t
RPLH
t
RPHL
RSKEW
t
RZH
t
RHZ
t
RWAKERL
t
RZL
t
RLZ
SHDN
RL = 500Ω, CL = 50pF, Figure 4 1000 ns
RL = 500Ω, CL = 50pF, Figure 4 8 µs
RL = 500Ω, CL = 50pF, Figure 5 1500 ns
RL = 500Ω, CL = 50pF, Figure 5 2000 ns
RL = 500Ω, CL = 50pF, Figure 5 8 µs
RL = 500Ω, CL = 50pF 12 µs
,
CL = 20pF, VID = 2V, VCM = 0V,
Figure 6
CL = 20pF, t
Figure 6
RL = 1kΩ, CL = 20pF, Figure 7 1000 ns
RL = 1kΩ, CL = 20pF, Figure 7 150 ns
= 1kΩ, CL = 20pF, Figure 7 5 µs
RL = 1kΩ, CL = 20pF, Figure 7 1000 ns
RL = 1kΩ, CL = 20pF, Figure 7 150 ns
RL = 500Ω, CL = 50pF 200 ns
RSKEW
= [t
RPLH
- t
RPHL
2000 ns
],
200 ns
DRIVER
Driver Differential Propagation
Delay
Driver Differential Output
Transition Time
Differential Driver Output Skew t
Maximum Data Rate f
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS
t
,
DPLH
t
DPHL
, t
t
LH
DSKEW
MAX
RL = 54Ω, CL = 50pF, Figure 3 800 ns
HLRL
= 54Ω, CL = 50pF, Figure 3 100 1200 ns
RL = 54Ω, CL = 50pF, t
], Figure 3
t
DPHL
DSKEW
= [t
DPLH
-
500 kbps
200 ns
MAX13448E
±80V Fault-Protected Full-Duplex
RS-485 Transceiver
_______________________________________________________________________________________ 5
SWITCHING CHARACTERISTICS (VCC= +5V ±10%) (continued)
(TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +5V and TA= +25°C.)
)
)
Note 2: Parameters are 100% production tested at TA= +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 ΔVOCare the changes in VODand VOC, 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.
D r i ver E nab l e Ti m e to Outp ut H i g ht
Driver Disable Time from
Output High
Driver Enable Time from
Shutdown to Output High
Driver Enable Time to Output Low t
Driver Disable Time from
Output Low
Driver Enable Time from
Shutdown to Output Low
Driver Time to Shutdown t
RECEIVER
Receiver Propagation Delay
Receiver Output Skew t
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
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS
DZH
t
DHZ
t
DZH(SHDN
DZL
t
DLZ
t
DZL(SHDN
SHDN
t
RPLH
t
RPHL
RSKEW
t
RZH
t
RHZ
t
RWAKERL
t
RZL
t
RLZ
SHDN
RL = 500Ω, CL = 50pF, Figure 4 1500 ns
RL = 500Ω, CL = 50pF, Figure 4 1000 ns
RL = 500Ω, CL = 50pF, Figure 4 8 µs
RL = 500Ω, CL = 50pF, Figure 5 1000 ns
RL = 500Ω, CL = 50pF, Figure 5 2 µs
RL = 500Ω, CL = 50pF, Figure 5 8 µs
RL = 500Ω, CL = 50pF 12 µs
,
CL = 20pF, VID = 2V, VCM = 0V,
Figure 6
CL = 20pF, t
Figure 6
RL = 1kΩ, CL = 20pF, Figure 7 1000 ns
RL = 1kΩ, CL = 20pF, Figure 7 150 ns
= 1kΩ, CL = 20pF, Figure 7 8 µs
RL = 1kΩ, CL = 20pF, Figure 7 1000 ns
RL = 1kΩ, CL = 20pF, Figure 7 150 ns
RL = 500Ω, CL = 50pF 150 ns
RSKEW
= [t
RPLH
- t
RPHL
],
2000 ns
200 ns
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