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SN65LBC184RS485/RS422收发器产品详情

The SN75LBC184 and SN65LBC184 are differ-ential data line transceivers in the trade- standard footprint of the SN75176 with built-in protection against high-energy noise transients.This featureprovides a substantial increase in reliability for better immunity to noise transients coupled to thedatacable over most existing devices.Use of these circuits provides a reliable low-cost direct-coupled (withnoisolation transfomer) data line interface without requiring any external components.

The SN75LBC184 and SN65LBC184 can with-stand overvoltage transients of 400-Wpeak (typical). The conventional combination wave called out in IEC 61000-4-5 simulates the overvoltage transientand models a unidirectional surge caused by overvoltages from switching and secondary lightningtransients. A biexponential function defined by separate rise and fall times for voltage and current simulatesthe combination wave.The standard 1.2 μs/50μs combination waveform is shown in Figure 1andinthe test description in Figure 15.

The device also includes additional desirable features for party-linedata buses in electricallynoisy environment applications including industrial process control.The differential-driver designincorporates slew-rate-controlled outputs sufficient to transmit data up to 250 kbps.Slew-ratecontrolallows longer unterminated cable runs and longer stub lengths from the main backbone than possiblewithuncontrolled and faster voltage transitions.A unique receiver design provides a fail-safe output of ahighlevel when the inputs are left floating(open circuit).

The SN75LBC184 and SN65LBC184 receiver alsoincludes a high input resistance equivalent to one-fourth unit load allowing connection of up to 128similardevices on the bus.

The SN75LBC184 is characterized for operation from 0℃ to 70℃.The SN65LBC184 is characterizedfrom-40℃to 85℃.