ADI ADM485ANZ

ТрансиверRS422, RS4855 Мбит/с

Overview

The ADM485ANZ is a differential line transceiver suitable for high speed bidirectional data communication on multipoint bus transmission lines. It is designed for balanced data transmission and complies with EIA standards RS-485 and RS-422. The part contains a differential line driver and a differential line receiver.Both the driver and the receiver can be enabled independently.When disabled, the outputs are three-stated. The ADM485ANZ operates from a single 5 V power supply.Excessive power dissipation caused by bus contention or by output shorting is prevented by a thermal shutdown circuit. Ifduring fault conditions,a significant temperature increase is detected in the internal driver circuitry, this feature forces the driver output into a high impedance state. Up to 32 transceivers can be connected simultaneously on a bus, but only one driver should be enabled at any time. It is important, therefore, that the remaining disabled drivers do not load the bus. To ensure this, the ADM485ANZ driver features high output impedance when disabled and when powered down, which minimizes the loading effect when the transceiver is not being used. The high impedance driver output is maintained over the common-mode voltage range of -7 V to +12V.

The receiver contains a fail-safe feature that results in a logic high output state if the inputs are unconnected(floating). The ADM485ANZ is fabricated on BiCMOS, an advanced mixed technology process combining low power CMOS with fast switching bipolar technology. 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. The ADM485ANZ features extremely fast switching speeds. Minimal driver propagation delays permit transmission at data rates up to 5 Mbps while low skew minimizes EMI interference. The part is fully specified over the commercial and industrialtemperature range and is available in 8-lead PDIP,8-lead SOIC, and small footprint,8-lead MSOP packages. FEATURES Meets EIA RS-485 standard 5 Mbps data rate Single 5 V supply –7 V to +12 V bus common-mode range High speed, low power BiCMOS Thermal shutdown protection Short-circuit protection Driver propagation delay: 10 ns typical Receiver propagation delay: 15 ns typical High-Z outputs with power off Superior upgrade for LTC485 APPLICATIONS Low power RS-485 systems DTE/DCE interface Packet switching Local area networks (LNAs) Data concentration Data multiplexers Integrated services digital network (ISDN) 

Features

Applications

• Ethernet circuitry
• Wired telephone
• Cordless telephone
• Desktop PC
• Notebook
• Pocket PC
• Desktop radio
• Clock radio
• Tuner
• Portable radio