Three Bidirectional Transceivers
Driver Meets or Exceeds the Requirements
of ANSI EIA/TIA-422-B and RS-485 and ITU
Recommendation V.11
Two Skew Limits Available
Designed to Operate Up to 20 Million Data
Transfers per Second (FAST-20 SCSI)
High-Speed Advanced Low-Power Schottky
Circuitry
Low Pulse Skew . . . 5 ns Max
Designed for Multipoint Transmission on
Long Bus Lines in Noisy Environments
Features Independent Driver Enables and
Combined Receiver Enables
Wide Positive and Negative Input/Output
Bus Voltages Ranges
Driver Output Capacity . . . ±60 mA
Thermal Shutdown Protection
Driver Positive- and Negative-Current
Limiting
Receiver Input Impedances . . . 12 kW Min
Receiver Input Sensitivity . . . ±300 mV Max
Receiver Input Hysteresis . . . 60 mV Typ
Operates From a Single 5-V Supply
Glitch-Free Power-Up and Power-Down
Protection

description
The SN75ALS171 and the SN75ALS171A triple differential bus transceivers are monolithic integrated circuits
designed for bidirectional data communication on multipoint bus transmission lines. They are designed for
balanced transmission lines, and each driver meets ANSI Standards EIA/TIA-422-B and RS-485 and both the
drivers and receivers meet ITU Recommendation V.11. The SN75ALS171A is designed for FAST-20 SCSI and
can transmit or receive data pulses as short as 30 ns with a maximum skew of 5 ns.
The SN75ALS171 and the SN75ALS171A operate from a single 5-V power supply. The drivers and receivers
have individual active-high and active-low enables, respectively, which can be externally connected together
to function as a direction control. The driver differential output and the receiver differential input pairs 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 is at 0 V. These ports feature wide positive and negative
common-mode voltage ranges making the device suitable for party-line applications.
The SN75ALS171 and the SN75ALS171A are characterized for operation from 0°C to 70°C.