Specifications

26 Maxim Industrial Solutions
Programmable logic controllers (PLCs)
Fieldbus functions
Benefits
• Flexible configurations interface to
many applications, thus reducing
inventory
– Pin-selectable 100Ω/120Ω termination
resistors eliminate external components
– Pin-selectable slew-rate limiting
improves EMI performance
– Integrated V
L
pin (down to 1.62V) allows
interfacing with mixed-voltage systems
• Integrated protection is ideal for harsh
environments
– Thermal shutdown at +150°C
– Fail-safe operation
– High ±30kV (HBM) ESD protection
• Robust, -40C to +125°C automotive
temperature grade
• Fault output warns user of short circuits
MAX13450E*/MAX13451E*
RS-485 half-duplex and full-duplex networks operating at high
data rates must have their transmission lines terminated at both
ends in order to minimize reflections from termination-impedance
mismatch. To perform the termination, typically discrete resistors are
either put into the equipment or added externally at the end-point
devices on the line. Most commonly, 120Ω transmission lines are
used in RS-485 applications. Recently, however, 100Ω lines have
become preferred because they use Ethernet cables.
The new RS-485 transceivers like the MAX13450E/MAX13451E
eliminate the need for external termination resistors because they
integrate pin-selectable 100Ω/120Ω resistors. The integrated logic-
level translation (V
L
pin) provides compatibility with mixed-voltage
systems.
* Future product—contact factory for availability.
RS-485 transceivers with integrated termination simplify equipment installation
RS-485 transceivers integrate all functions needed for robust industrial communications.
Software-/pin-selectable
termination allows remote
network conguration
Integrated termination
resistors support both
100Ω and 120Ω cables
Switchable termination
eliminates external resistors
and DIP switches
SLAVE 1 SLAVE 2 END SLAVE
MAX13451E*
D
R
MASTER