HI-8437

January 2016 HI-8437 32-Channel High Impedance Low Threshold Sensor with SPI Interface GENERAL DESCRIPTION The HI-8437 is a 32-channel high impedance discrete-todigital 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 400KΩ 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 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. 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 microcontroller...