F81485 Datasheet, PDF (4/12 Pages) Feature Integration Technology Inc. – 5V Low Power RS-485 Interface Transceiver

1 General Description
F81485
The F81485 is a CMOS design, features with single 5 V power supply, and low power differential
bus/line transceiver suitable for the multipoint data transmission EIA standard RS485 and RS422
applications. The extended common-mode range is −7 V to +12 V. Both the driver and the receiver
can be enabled independently. The driver and receiver feature three-state outputs, with the driver
outputs maintaining high impedance over the entire common-mode range. Excessive power
dissipation caused by the bus contention or faults is prevented by a thermal shutdown circuit which
forces the driver outputs into a high impedance state. The receiver contains a fail-safe feature that
results in a logic high output state if the inputs are unconnected (floating). Up to 32 transceivers can
be connected simultaneously on a bus, but only one driver should be enabled at any time. The
F81485 features extremely fast switching speeds. Minimal driver propagation delays permit
transmission at data rates up to 5 Mbps while low skew minimizes EMI interference. All inputs and
outputs contain protection against ESD; all driver outputs feature high source and sink current
capability. An epitaxial layer is used to guard against latch-up.
2 Feature List
z Single 5V Supply
z Meets EIA RS-485 standard
z High speed, low power BiCMOS
z -7V to 12V Bus Common-Mode Range Permits
z ±7V Ground Difference Between Devices on the Bus
z ESD ±8KV Contact
z Thermal Shutdown Protection
z Driver Maintains High Impedance in Three-State or with the Power Off
z 70mV Typical Input Hysteresis
z Driver propagation delay: 10 ns typical
z Receiver propagation delay: 15 ns typical
z High-Z outputs with power off
z Pin Compatible with the ADM485, SP485
z 8 Pin SOP Packaging
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Jan, 2012
V0.11P