HI-8429 Datasheet, PDF (1/20 Pages) Holt Integrated Circuits – Interrupt generated on any change of sensor state

February 2015
HI-8429
8-Channel GND/Open or Supply/Open Sensor
with Programmable Thresholds and SPI Interface
GENERAL DESCRIPTION
The HI-8429 is an 8-channel discrete-to-digital sensor
fabricated with Silicon-on-Insulator (SOI) technology
designed to interface with a Serial Peripheral Interface
(SPI).
Each input is individually configurable as either GND/Open
or Supply/Open (28V/Open). Discrete input thresholds are
programmable in the range of 2V to 12V. An SPI bus is
used to configure the sensors and to read sensor data .
The part operates from a 3.3V (±5%) digital supply and
12V to 15V analog supply.
A 1mA wetting current is sourced from the input network on
each SENSE input when GND/Open mode is selected for
that pin. The wetting current serves to prevent dry relay or
switch contacts. An optional debounce circuit also ensures
sensor outputs respond correctly to mechanical sensor
inputs. A sensor output interrupt pin alerts the system to a
change in sensor input, avoiding constant polling via SPI to
check status.
All sense inputs are internally lightning protected to
RTCA/DO160G, Section 22 Level 3 Pin Injection Test
Waveform Set A(3 & 4), Set B (3 & 5A) and Set Z (3 & 5B)
without the using external components.
Higher levels of lightning protection can be achieved with
an external series resistor and transorb at each SENSE
input, refer to AN305 for more details.
APPLICATION
· Avionics Discrete to Digital Sensing
FEATURES
· Robust CMOS Silicon-on-Insulator (SOI) technology
· Eight discrete inputs, individually configurable as
GND/Open or Supply/Open
· Interrupt generated on any change of sensor state
· SPI programmable sensor thresholds
· Sensor data read through SPI bus
· Airbus ABD0100H specification compliant
· MIL-STD-704 compliant
· Sense inputs lightning protected to RTCA/DO1060G,
Section 22 Level 3
· 10MHz Serial Peripheral Interface (SPI) allows daisy-
chaining of parts for efficient board routing
· Withstands inadvertent application of 115V AC/400Hz
power to Sense inputs.
· Internal Self-Test mode checks analog comparators
PIN CONFIGURATION
DNBC 1
SENSE1 2
SENSE2 3
SENSE3 4
SENSE4 5
SENSE5 6
SENSE6 7
SENSE7 8
SENSE8 9
INT 10
HI-8429PSx
20 SEL1
19 VDD
18 GND
17 VLOGIC
16 SEL0
15 SI
14 CS
13 SCK
12 SO
11 MR
20-Pin Plastic Small Outline
Wide-body Package
(DS8429 Rev. B)
HOLT INTEGRATED CIRCUITS
www.holtic.com
02/15