Space-system-qualified hi-rel temperature sensor

November 08, 2013 // By Graham Prophet
Intersil’s ISL71590SEH requires 1.5mW (25°C) power, provides ±1.7°C accuracy and -1°C shift over low dose rate radiation

ISL71590SEH is a radiation-hardened, low power, current output temperature sensor able to deliver a high level of accuracy over radiation exposure, time and temperature, and is intended for remote temperature sensing in satellites and other space applications.

Developers of the most advanced next generation satellite systems require temperature sensors that provide accuracy over the mission life of a satellite, eliminating the need for expensive radiation lot acceptance testing or spot shielding. With the ISL71590SEH’s ±1.7°C accuracy over temperature and at most -1°C change in accuracy over low dose rate radiation, the device is able to serve satellite temperature sensing functions that support most of a system’s telemetry data and calibration accuracy. The ISL71590SEH provides highly accurate, reliable temperature sensing and linearity over the full military temperature range of -55°C to 125°C, as well as over 50krad (Si) low dose rate and 300krad (Si) high dose rate irradiation.

The ISL71590SEH temperature sensor features a high impedance current output that allows the part to be insensitive to voltage drops across long wires. With a voltage between 4V and 33V on the input pin, the ISL71590SEH acts as a temperature sensitive current source with a scale factor of 1 μA/K (i.e. 1 μA/°C). It operates over the full temperature range without the need of additional circuitry, to produce results with ±1.7°C accuracy.

The ISL71590SEH also offers power advantages, with requirements as low as 1.5mW (5V supply at 25°C). This allows it to be used in satellite signal chains and in applications such as temperature compensation networks, flow rate analysis, and biasing proportional to temperature.

Long term stability ensures accurate measurements, ±0.25°C over 1000 hours at +125°C. A high output impedance of over 10MΩ allows variations in the power supply voltage; it can withstand a forward voltage of 40V outside of heavy ion radiation (37V under 86 MeV·cm 2/mg heavy ion irradiation) and a reverse voltage of 40V. In a 2-terminal isolated flatpack