ST485ABN

ST485AB Very high speed low power RS-485/RS-422 transceiver Features ■ Low supply current: 5 mA max ■ High data rate > 30 Mbps ■ Designed for RS 485 interface applications ■ -7 to 12 common mode input voltage range ■ Driver maintains high impedance in 3-state or with the power off ■ 70mV typical input hysteresis ■ Operate from single 5 supply ■ ±4 kV ESD protection ■ Current limiting and thermal shutdown for driver overload protection ■ DIP-8 SO-8 The ST485A is designed for bi-directional data communications or multipoint bus transmission lines. Latch-up free up to 500 mA Description The ST485A is a low power, high speed transceiver for RS-485 and RS-422 communications. The device contains one driver and one receiver in half duplex configuration. The ST485A draws 3 mA (typ.) of supply current when unloaded or fully loaded with disabled drivers. It operates from a single 5 V supply. Driver is short-circuit current limited and is protected against excessive power dissipation by thermal shutdown circuitry that place the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic high output if both inputs are open circuit. Table 1. Device summary Order code Temperature range Package Packaging ST485ABN -40 to 85 °C DIP-8 50parts per tube / 40tube per box ST485ABDR -40 to 85 °C SO-8 (Tape & reel) 2500 parts per reel August 2007 Rev. 3 1/19 www.st.com 19 Contents ST485AB Contents 1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Test circuit and typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2/19 ST485AB Pin configuration 1 Pin configuration Figure 1. Pin configuration Table 2. Pin description Pin n° Symbol Name and function 1 RO Receiver output. If A>B by 200 mV, RO will be high; if A