LMS485 Datasheet | National Semiconductor

Description The LMS485 is a low power differential bus/line transceiver designed for high speed bidirectional data munication on multipoint bus transmission lines. It is designed for balanced transmission lines. It meets ANSI Standards TIA/EIA RS422B, TIA/EIA RS485-A and ITU remendation and V.11 and X.27. The LMS485 bines a TRI-STATE® differential line driver and differential input receiver, both of which operate from a single 5.0V power supply. The driver and receiver have an active high and active low, respectively, that can be externally connected to function as a direction control. The driver and receiver differential inputs are internally connected to form differential input/output (I/O) bus ports that are designed to offer minimum loading to bus whenever the driver is disabled or when VCC = 0V. These ports feature wide positive and negative mon mode voltage ranges, making the device suitable for multipoint applications in noisy environments. The LMS485 is available in a 8-Pin SOIC and 8-Pin DIP packages. It is a drop-in socket replacement to Maxim’s MAX485 Features - Meet ANSI standard RS-485-A and RS-422-B - Data rate 2.5 Mbps - Single supply voltage operation, 5V - Thermal shutdown protection - Short circuit protection - Low power Bi CMOS - Allows up to 32 transceivers on the bus - Open circuit fail-safe for receiver - Extended operating temperature range - 40°C to 85°C - Drop-in replacement to MAX485 - Available in 8-pin SOIC and 8-Pin DIP package Applications - Low power RS-485 systems - Network hubs, bridges, and routers - Point of sales equipment (ATM, barcode scanners,…) - Local area networks (LAN) - Integrated service digital network (ISDN) - Industrial programmable logic controllers - High speed parallel and serial applications - Multipoint applications with noisy environment Typical Application A Typical multipoint application is shown in the above figure. Terminating resistors, RT, are typically required but only located at the two ends...