Intersil rad-hard multiplexers offer ESD protection

Intersil has introduced rad hard multiplexers that offer ESD protection, signal chain accuracy and timing performance.

ESD protection ISL71840SEHEV1Z, and ISL71841SEHEV1Z

The ISL71840SEH 30V 16-channel multiplexer is a drop-in replacement for Intersil’s widely adopted HS9-1840ARH, which has been aboard nearly every satellite and space exploration mission, including NASA’s recent Orion spacecraft flight test.

For applications with form factor constraints, the ISL71841SEH 30V 32-channel multiplexer offers high performance and 41% reduced board space compared with an ISL71840SEH two-chip solution.

The ISL71840SEH and ISL71841SEH use Intersil’s proprietary SOI process which provides single event latch-up (SEL) robustness in heavy ion environments. The enhanced 8kV ESD protection feature of these devices eliminates the need for external protection diodes on the input pins.

Their reduced RON of 500Ω at ±5V and propagation delays of less than 800ns increase the overall performance and accuracy of telemetry signals processed and multiplexed into an ADC input.

The ISL71840SEH and ISL71841SEH offer over-voltage protection on a per-switch basis to maintain the continuous processing 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 two or three additional unpowered multiplexers to a common data bus. This is an especially important feature for mission-critical space flights lasting up to 20 years.

If required for any reason, a redundant multiplexer is immediately activated. Both multiplexers provide a wide supply range with split-rail operation from ±10.8V to 16.5V and an absolute maximum of ±20V, providing designers with plenty of de-rating headroom.

Key features and specifications:

Delivers 8kV human body model (HBM) ESD protection
Provides true rail-to-rail operation and features over-voltage protection with shutoff
Cold sparing from ground +/-25V and analog over-voltage range from ground ±35V
Off switch leakage of 100nA and low RON of less than 500 Ohms reduces power consumption, and improves signal integrity and total harmonic distortion
Triple redundant decoders with a fast response time of <5us drastically improves single event transient (SET) performance
Improved off-isolation and crosstalk rejection ensures the output leaks to ground whenever the multiplexer is disabled
Adjustable logic threshold control with VREF pin
High dose rate (50-300rad(Si)/s) radiation tolerance of 100krad(Si)
Low dose rate (0.01rad(Si)/s) radiation tolerance of 50krad(Si)
SEL/B immune up to 86MeV.cm²/mg

The ISL71840SEH and ISL71841SEH multiplexers can be combined with the ISL71590SEH rad hard temperature sensor, ISL71090SEH25 voltage reference, and operational amplifiers such as the ISL70444SEH, ISL70244SEH, ISL70417SEH, ISL70218SEH, ISL70227SEH, ISL70419SEH to support a complete analog signal chain with superior radiation tolerant performance.

The ISL71840SEH 16-channel multiplexer is available in an 18.8x14mm, 28-lead ceramic flatpack package, and the ISL71841SEH 32-channel multiplexer comes in a 14x14mm, 48-lead ceramic quad flatpack. Both multiplexers are also available in die form. Two evaluation boards are available to evaluate device features and performance: 16-channel ISL71840SEHEVAL1Z and 32-channel ISL71841SEHEVAL1Z.