DEI1282-SES-G

DEI1282 and DEI1284 are eight-channel discrete-to-digital interface ICs implemented in a High Voltage Dielectric Isolated technology. They sense eight discrete signals of the type commonly found in avionic systems and convert them to serial logic data. Each input can be individually configured as either GND/OPEN or 28V/OPEN format input via a serial data input. 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.

Features

• Eight discrete inputs
• Individually configurable as either GND/OPEN or 28V/OPEN(GND) inputs.
• Input threshold and hysteresis per AirBus ABD0100H specification.
• GND/OPEN mode: 4.5V/10.5V threshold, 3V hysteresis
• 28V/OPEN mode: 6V/12V threshold, 3V hysteresis
• 1mA input current to prevent dry relay contacts.
• Internal isolation diodes
• Inputs protected from Lightning Induced Transients per DO160F, Section 22, Cat A3 and B3
• 1284 version supports higher lightning levels and input filtering via use of off-chip input resistors
• Withstands inadvertent application of 115VAC/400Hz power
• Built-in Test (BIT) to test internal circuits including input comparator
• Serial I/O interface to read data register and write configuration register
• Direct interface to Serial Peripheral Interface (SPI) port.
• TTL/CMOS compatible inputs and Tristate output
• 8.6MHz Max Data Rate
• Serial input to expand Shift Register
• Logic Supply Voltage (VCC): 3.3V +/-5%
• Analog Supply Voltage (VDD): 12V to 16.5V
• 16L SOIC EP package

Attributes

Functional Description DEI1282 and DEI1284 are eight-channel discrete-to-digital interface ICs implemented in a High Voltage Dielectric Isolated technology. They sense eight discrete signals of the type commonly found in avionic systems and convert them to serial logic data. Each input can be individually configured as either GND/OPEN or 28V/OPEN format input via a serial data input. 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 inputs are implemented with a high voltage technology to provide immunity to lightning induced transients. The DEI1282 tolerates DO160F Level 3 (600V) stress directly to the input pins without the need for additional protection components. The DEI1284 version operates with 3K Ohm off-chip series resistors on the inputs. These are used in combination with Transient Voltage Suppressor (TVS) devices to achieve Level 4 (1500V) and Level 5 (3200V) immunity. The resistors act to limit surge current, thus allowing small TVS devices. The resistors are also used to implement low pass filtering by adding capacitors on the inputs. The filtering provides noise rejection and anti-aliasing of the sampled signal. The on-chip Built-in Test (BIT) feature provides a Test Mode which provides a means to inject a test signal into each input comparator without interfering with the discrete input signals. The test coverage includes each DIN comparator as well as the digital logic and IO.