The HI-8436 is a 32-channel discrete-to-digital sensor fabricated with Silicon-on-Insulator (SOI) technology designed to interface with a Serial Peripheral Interface (SPI).

Four banks of 8 sense inputs can be programmed as either GND/Open or Supply/Open sensors. Supply/Open sensing is also referred to as 28V/Open sensing.

All sense inputs are internally lightning protected to DO160G, Section 22, Cat AZ, BZ and ZZ  without external components.   

The sensing circuit window comparator thresholds are set by programming the center threshold and hysteresis  registers to values from 0.4V to 5.2V. The digital values of the sensed inputs can be read either one bank at a time or all 4 banks with one command.

Each bank of sensors have a VWETn pin available for optional application of a voltage higher than the logic supply to provide wetting current to Ground side relay contacts. If the Ground offset is small, then the wetting source will automatically be provided from VLOGIC without connecting VWETn.

Interface to the digital subsystem is simple CMOS logic inputs and outputs. The logic pins are compatible with 3.3V logic allowing direct connection to a wide range of microcontrollers or FPGAs.




  • 32-channel Selectable Sense Operation, GND/Open or 28V/Open
  • Programmable Thresholds and Hysteresis in 0.1V steps from 0.4V to 5.2V
  • Lightning Protected Sense Inputs
  • Single low voltage supply operation for low threshold applications
  • Logic operation from 3.0V to 3.6V
  • 20MHz Serial Peripheral Interface (SPI)
  • Internal self-test
  • Robust CMOS Silicon-on-Insulator (SOI) technology
  • Industrial & extended temperature ranges available



  • Avionics discrete sensing applications



ADK-8436: HI-8436 Discrete-to-Digital Sensor Evaluation Board

ADK-8436: HI-8436 Discrete-to-Digital Sensor Evaluation Board

The Holt HI-8436 Evaluation Board demonstrates the features of the HI-8436, a 32 channel Ground/Open or 28V/Open discrete-to-digital sensor IC with SPI interface. The HI-8436 has a low threshold sensing capability, programmable in 100mV increments from 0.4V to 5.2V. The EVM (Evaluation Module) plugs into a Holt ‘General Purpose SPI Evaluation Board, based on a Freescale MC9S12XDT512 microcontroller motherboard. The motherboard MCU communicates with the HI-8436 via the SPI interface.
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