The HI-8437 is a 32-channel high impedance discrete-to-digital sensor fabricated with Silicon-on-Insulator (SOI) technology designed to interface with a Serial Peripheral Interface (SPI).


The four banks of 8 sense inputs can be programmed to detect one of two threshold ranges, VTHR1, VTHR2.


All sense inputs have a 400 kΩ resistor to ground and 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 1.0V 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.


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 programmable sense operation with two programmable threshold ranges
  • Programmable Thresholds and Hysteresis in 0.1V steps from 1.0V to 5.2V
  • Lightning Protected Sense Inputs
  • Single low voltage supply operation
  • 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
  • Low thresholds applications



ADK-8437: HI-8437 Discrete-to-Digital Sensor Evaluation Board

ADK-8437: HI-8437 Discrete-to-Digital Sensor Evaluation Board

The Holt HI-8437 Evaluation Board demonstrates the features of the HI-8437, a 32 channel discrete-to-digital sensor IC with SPI interface and high impedance inputs. The HI-8437 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-8437 via the SPI interface.
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