Differential Bus Transceiver

The SN65176B and SN75176B differential bus

transceivers are designed for bidirectional data communication on multipoint bus

transmission lines. The SN65176B and SN75176B are designed for balanced transmission

lines and meet ANSI Standards TIA/EIA-422-B and TIA/EIA-485-A and ITU

Recommendations V.11 and X.27.

The SN65176B and SN75176B devices combine a

3-state differential line driver and a differential input line receiver, both of

which operate from a single 5V power supply. The driver has a active-high enable and

the receiver has an active-low enable, that can connect together externally to

function as a direction control. The driver differential outputs and the receiver

differential inputs are connected internally to form differential input/output (I/O)

bus ports that are designed to offer minimum loading to the bus when the driver is

disabled or VCC = 0. These ports feature wide positive and negative

common-mode voltage ranges, making the device appropriate for party-line

applications.

The driver is designed for up to 60mA of sink or

source current. The driver features positive and negative current limiting and

thermal shutdown for protection from line-fault conditions. Thermal shutdown is

designed to occur at a junction temperature of approximately 150°C. The receiver

features a minimum input impedance of 12kΩ, an input sensitivity of ±200mV, and a

typical input hysteresis of 50mV.