Radiation-tolerant devices for space-borne data circuitry

March 08, 2016 // By Graham Prophet
Intersil has expanded its rad-tolerant range with 5V multiplexers for space flight systems; the ISL71830SEH and ISL71831SEH provide optimised ESD protection and signal processing performance.

These single supply 5V devices, the 16-channel ISL71830SEH and 32-channel ISL71831SEH multiplexers, join Intersil's 30V multiplexers, which have been on-board nearly every satellite and space exploration mission, including NASA's Orion spacecraft flight test. The 5V multiplexers address the growing trend toward reduced system voltage rails. They provide data acquisition systems with the industry's best electrostatic discharge (ESD) protection, and deliver lower R ON and input leakage for reduced power consumption and higher signal integrity. The 5V multiplexers also offer faster propagation delays, which significantly improve signal processing response time.


The ISL71830SEH and ISL71831SEH claim doubled performance relative to their competition through use of a silicon on insulator process, which provides single event latch-up (SEL) robustness in heavy ion environments. The devices' 5 kV ESD protection feature eliminates the need for external protection diodes on the input pins. Both multiplexers have reduced R ON of 120 Ohms and propagation delays of less than 100 nsec to increase the overall performance and accuracy of telemetry signals processed and multiplexed into an ADC input.


The ISL71830SEH and ISL71831SEH offer over-voltage protection on a per-switch basis to maintain the continuous processing of hundreds of telemetry test points. If any input channel experiences an over-voltage condition, the remaining channels continue sending data to the ADC. Both multiplexers provide a "cold spare" redundant capability, allowing the connection of 2-3 additional unpowered multiplexers to a common data bus. This mission-critical feature is required for long duration space flights. The system automatically activates the backup multiplexer should a failure occur.


The parts feature 3V to 5.5V single supply operation with adjustable logic threshold control; deliver 5 kV human body model (HBM) ESD protection; have rail-to-rail switch inputs to provide wide dynamic range for extra design flexibility and have an over-voltage shutoff that protects upstream/downstream devices when a switch goes 1V-2V past the rails. They provide cold sparing and analogue overvoltage range from -0.4V to 7V;