The HI-31821 is a multi-function line driver which can meet the ARINC 429 bus specification (differential BRZ data output), or the RS-422 bus specification (differential NRZ data output). The device is a form, fit, function drop-in replacement for the Device Engineering Inc. (DEI) BD429.

Inputs are provided for clocking and synchronization. These signals are AND’d with the DATA inputs to enhance system performance and allow the device to be used in a variety of applications. Both logic and synchronization inputs feature built-in ESD input protection as well as
TTL and CMOS compatibility.

The differential outputs are independently programmable to either the high speed or low speed ARINC 429 output rise and fall time specifications through the use of two external capacitors. The output voltage swing is also adjustable by the application of an external voltage to the VREF input. The device has on-chip Zener diodes in series with a fuse to each differential output protecting the ARINC bus from an overvoltage failure. The outputs each have a series resistance of 37.5 ohms.

Features

• Drop-in replacement for DEI BD429
• TTL and CMOS compatible inputs
• Programmable output voltage swing
• Adjustable ARINC 429 rise and fall times using external capacitors
• RS-422 line driver mode selection using digital input pin
• Overvoltage Protection
• Low power CMOS
• Industrial & Extended Temperature Ranges Available

Applications

• Avionics Data Communication
• CMOS/TTL to ARINC 429 or RS-422 Level Conversion