The devices have a 12 kΩ receiver input impedance which allows up to 32 transceivers on a bus. Since only one driver should be enabled at any time, the output of a disabled or powered down driver is three-stated to avoid overloading the bus. The driver outputs of the ADM3486E are slew rate limited in order to reduce EMI and data errors caused by reflections from improperly terminated buses. The receiver has a failsafe featurewhich ensures a logic high output when the inputs are floating. Excessive power dissipation caused by bus contention or by output shorting is prevented with a thermal shutdown circuit. The parts are fully specified over the commercial and industrial temperature ranges and are available in narrow 8-lead and 14-lead (ADM3491E) SOIC packages.
Feature
- TIA/EIA RS-485/RS-422 compliant
- ±15 kV ESD-protection on RS-485 input/output pins
- Data rates - ADM3490E/ADM3491E: 12 Mbps
- Full duplex
- 32 nodes on the bus
- Receiver open-circuit, fail-safe design
- Outputs high-Z when disabled or powered off
- −7 V to +12 V common-mode input range
- Thermal shutdown and short-circuit protection
- Industry-standard 75176 pinout
- 8-lead SOIC package
(Picture: Pinout)
