Three Bidirectional Transceivers
Driver Meets or Exceeds ANSI Standard
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
Designed for Multipoint Transmission on
Long Bus Lines in Noisy Environments
Wide Positive and Negative Input/Output
Bus Voltage 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
Operate From a Single 5-V Supply
Glitch-Free Power-Up and Power-Down
Protection
Feature Independent Direction Controls for
Each Channel

description
The SN75ALS170 and SN75ALS170A triple differential bus transceivers are monolithic integrated circuits
designed for bidirectional data communication on multipoint bus transmission lines. It is designed for balanced
transmission lines and the driver meets ANSI Standards EIA/TIA-422-B and RS-485 and both the driver and
receiver meet ITU Recommendation V.11. The SN75ALS170A 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 SN75ALS170 and SN75ALS170A operate from a single 5-V power supply. The drivers and receivers have
active-high and active-low enables, respectively, which are internally connected together 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 suitable for party-line applications.
The SN75ALS170 and the SN75ALS170A are characterized for operation from 0°C to 70°C.