New Discrete-to-Digital Sensor with Programmable Sense Thresholds and Internal Lightning Protection

Tuesday, October 21, 2014

Mission Viejo, CA (October 21, 2014) - Holt Integrated Circuits today announced a new discrete-to-digital sensor IC, HI-8429, an 8-channel device with programmable sense channels and internal lightning protection. The sense input thresholds are programmable via a 10MHz SPI bus and each channel may be individually configured as GND/Open or Supply/Open (28V/Open) sensors. Additional features include an optional debounce circuit and sensor output interrupt pin.

The HI-8429 operates from a 3.3V digital supply and 12V to 16.5V analog supply. The device is compliant with Airbus ABD0100H specification and has inputs individually configurable as either GND/Open or Supply/Open (28V/Open). Discrete input thresholds are programmable in the range of 2V to 14V.

In GND/Open mode a 1mA wetting current is sourced from the sense input to prevent dry relay 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 the latest Set Z (3 & 5B) without the use of any external components. Higher levels of lightning protection can be achieved with an external series resistor and transorb at each sense input; refer to application note AN-305 for more details.

“The HI-8429 builds on the feature set of the recently announced HI-8428 to include programmable thresholds, a debounce feature, and an output interrupt” said George Noh, Director of Sales and Marketing at Holt. “These enhanced features deliver a complete solution with ease of use and application flexibility in mind”.

The device is available in a 20-pin, wide-body SOIC with exposed heat pad. Samples are available upon request. Holt also provides a development kit with example software and source code to demonstrate all key device features.

To request information on Holt’s ARINC 429, CAN, MIL-STD-1553 and other aerospace products, readers should contact Holt at (949) 859-8800, by e-mail at, or visit the Holt Web site at



About Holt Integrated Circuits

Located in Mission Viejo, CA, Holt Integrated Circuits is a major supplier of ICs for avionics and military data bus and display applications. The company’s products are specified by more than 400 manufacturers worldwide and are employed in flight control, navigation, engine management, communications, safety equipment, and in-flight entertainment systems.

Holt’s range of ICs supporting the ARINC 429 standard is the widest in the industry and its MIL-STD-1553 transceivers are recognized as the industry’s smallest, having the lowest power consumption. In addition, Holt MIL-STD-1553 integrated terminals offer the most compact, cost effective solution available, integrating protocol, transceiver and transformers in a single 15x15mm package. Other data bus products include ARINC 717, CAN (ARINC 825), RS-485/422 and analog switches. Select products are available to DSCC SMD specifications. Holt also offers product compliant to the European Union "RoHS Directive 002/95/EC".

Holt Integrated Circuits is ISO 9001:2008 registered and is a STACK certified supplier and recipient of the STACK International 2012 Gold Supplier Award.











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