DEI1188 is an eight-channel discrete-to-digital interface IC implemented in an HV DIMOS technology. It senses eight
GND/OPEN discrete signals of the type commonly found in avionic systems and converts them to serial logic data. The
discrete data is read from the device via an eight-bit serial shift register with 3-state output. This serial interface is compatible
with the industry standard Serial Peripheral Interface (SPI) bus.
The discrete input circuits are designed to achieve a high level of lightning transient immunity. The application design
provides a series 3KΩ resistor on each discrete input to achieve DO160E Level 3 and WF5A 500V immunity. Higher
immunity levels can be achieved (i.e. Level 5) with the addition of a TVS between the resistor and the input pin.
Table 1 Pin Descriptions
Discrete Inputs. Eight GND/OPEN discrete input signals.
Logic Output. Serial Data Output. This pin is the output from MSB (Bit
8) of the data shift register. It is clocked by the rising edge of SCLK.
This is a 3-state output enabled by /CS.
Logic Input. Serial Shift Clock. A low-to-high transition on this input
shifts data on the serial data input into Bit 1 of the selected data register.
The data shift register is shifted from Bit 1 to Bit 8. Bit 8 of the data
shift register is driven on DOUT.
Logic Input. Chip Select. A low level on this input enables the SDO 3-
state output and the data shift register. A high level on this input forces
DOUT to the high impedance state and disables the shift registers so
SCLK transitions have no effect. A high-to-low transition causes the
Discrete Input data to be loaded into the Data Register.
Logic Input. Serial Data Input. Data on this input is shifted into the LSB
(Bit 1) of the data shift register on the rising edge of the SCLK when /CS
input is low.
Logic Supply Voltage. 3.3V+/-5%
Analog Supply Voltage. 12V to 16.5V
16 EP SOIC
16 EP SOIC
-55 / +125 ºC
-55 / +85 ºC
DEI reserves the right to make changes to any products or specifications herein. DEI makes no warranty, representation, or
guarantee regarding suitability of its products for any particular purpose.
©2009 Device Engineering Inc.
2 of 12
DS-MW-01188-01 Rev. D