HI-8435 Datasheet, PDF (1/21 Pages) Holt Integrated Circuits – 32-Channel Ground/Open or Supply/Open

July 2013
HI-8435
32-Channel Ground/Open or Supply/Open
Sensor with SPI Interface
GENERAL DESCRIPTION
The HI-8435 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 2V to 22V. 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.
FEATURES
· Robust CMOS Silicon-on-Insulator (SOI) technology
· 32-channel Programmable Sense Operation,
GND/Open or Supply/Open, 4 X 8 Input Sensors
· Programmable HI/LO Threshold and Hysteresis in
0.5V steps, from 2V to 22V.
· Single Low Voltage Supply Operation for low
thresholds applications.
· Logic Operation from 3.0V to 3.6V
· 20 MHz Serial Peripheral Interface (SPI)
· Lightning Protected Sense Inputs
· Airbus ABD0100H compliant
· MIL-STD-704 compliant
· Internal Self-Test
APPLICATION
· Avionics Discrete to Digital Sensing
PIN CONFIGURATIONS
VWET0 - 1
SENSE_0 - 2
SENSE_1 - 3
SENSE_2 - 4
SENSE_3 - 5
SENSE_4 - 6
SENSE_5 - 7
SENSE_6 - 8
SENSE_7 - 9
SENSE_8-10
SENSE_9-11
HI-8435PQI
HI-8435PQT
33 - SENSE_27
32 - VWET3
31 - SENSE_26
30 - SENSE_25
29 - SENSE_24
28 - SENSE_23
27 - SENSE_22
26 - SENSE_21
25 - SENSE_20
24 - SENSE_19
23 - SENSE_18
44 Pin Plastic Quad Flat Pack (PQFP)
10mm x 10mm
VWET0 - 1
SENSE_0 - 2
SENSE_1 - 3
SENSE_2 - 4
SENSE_3 - 5
SENSE_4 - 6
SENSE_5 - 7
SENSE_6 - 8
SENSE_7 - 9
SENSE_8 -10
SENSE_9 -11
HI-8435PC
33 - SENSE_27
32 - VWET3
31 - SENSE_26
30 - SENSE_25
29 - SENSE_24
28 - SENSE_23
27 - SENSE_22
26 - SENSE_21
25 - SENSE_20
24 - SENSE_19
23 - SENSE_18
44 Pin Plastic QFN
7mm x 7mm
(DS8435 Rev. C)
HOLT INTEGRATED CIRCUITS
www.holtic.com
07/13