The HI-8470 is a sixteen channel discrete-to-digital interface device. The IC has 16 channels which can sense Open/Ground or 28V/Open signal levels. The voltage threshold of the sensors is user programmable with external resistors. Sense input thresholds may also be set to CMOS logic levels to interface the part with other sensors, for example an external ADC. 


An on-chip ARINC 429 transmitter / line driver allows the status of discrete lines to be transmitted in ARINC 429 format with pin-programmed label byte value, repetition rate and transmission speed. Complete operation of the HI-8470 is controlled by CMOS logic pins, negating the need for an MCU or software in the application.


The device uses an on-chip DC/DC converter to generate the required ARINC 429 line voltages from a 3.3V supply. In addition, the discrete sense pins and line driver outputs are lightning protected to RTCA/DO-160G, Section 22 Level 3 Pin Injection Test Waveform Set A (3 & 4), Set B (3 & 5A) and Set Z (3 & 5B) without the use of any external components, resulting in additional component count and cost savings for the application. The user simply needs a single 3.3V power supply and a 1 MHz clock source, for ARINC 429 bit timing and word transmission rate scheduling.


The device is available in industrial −40oC to +85oC and extended −55oC to +125oC temperature ranges and comes in a 100 pin PQFP package.



  • Pin programmable - requires no MCU or software control (no need for DO-178 certification)

  • Robust CMOS Silicon-on-Insulator (SOI) technology

  • 16 sense-selectable (GND/Open or 28V/Open) discrete input channels

  • Programmable Thresholds and Hysteresis

  • Sense Detection Range 3V to 22V

  • On-chip ARINC 429 Transmitter and Line Driver

  • 3.3 V single supply operation

  • Pin programmable transmit repetition rate

  • Internal lightning protection (RTCA/DO-160G, Level 3 Pin Injection Tests) for Discrete Sense lines and ARINC 429 Line Driver

  • Adjustable  sense thresholds

  • DO-254 certifiable



  • Discrete-to-Digital sensing applications requiring ARINC 429 data transmission

  • Simple sensing applications requiring no MCU or software



ADK-8470: HI-8470 Application Development Kit

ADK-8470: HI-8470 Application Development Kit

The Holt HI-8470 Evaluation Board demonstrates features of the HI-8470 16 channel discrete-to-digital sensor with ARINC 429 transmitter. The board and the HI-8470 can be run from a single 3.3V supply voltage. The device has preset internal sensor thresholds and external thresholds can also be set with board-mounted potentiometers. The HI-8470 and Evaluation Module require no software for control; all functions are set by hardware switches. DIP switches configure the device and data inputs.
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ADK-8470 ADC: HI-8470 Sensor Evaluation Board

ADK-8470 ADC: HI-8470 Sensor Evaluation Board

The HI-8470 Sensor Evaluation Board illustrates the use of Holt’s HI-8470 with an analog sensor using an Analog to Digital Converter (ADC) to interface to the sensor. The sensor data output from the ADC is detected by the HI-8470 and re-transmitted on an ARINC 429 bus without a microcontroller interface. The board is self contained and requires no software; all functions are set by hardware switches.
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