Remote temperature sensing in space applications

In order to avoid the use of expensive radiation lot acceptance testing or spot shielding, temperature sensors which can provide accuracy over the mission life of a satellite are vitally important for developers of the most advanced next generation satellite systems. Meeting the requirement of satellite temperature sensing functions that support most of a system’s telemetry data and calibration accuracy, the ISL71590SEH features +/-1.7°C accuracy over temperature and at most -1°C change in accuracy over low dose rate radiation. Operating 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 offers highly accurate, reliable temperature sensing and linearity.

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

With requirements as low as 1.5mW (5V supply at 25°C), the ISL71590SEH offers power advantages as well. Therefore it is suitable for use in satellite signal chains and in applications such as temperature compensation networks, flow rate analysis, and biasing proportional to temperature.

Important features of Intersil's ISL71590SEH temperature sensor include: outstanding, industry leading high and low dose rate performance; excellent temperature accuracy and long term stability ensure accurate measurements (±0.25°C over 1000 hours at +125°C.); high output impedance (>10MΩ) allows variations in the power supply voltage; and it can withstand a forward voltage of 40V outside of heavy ion radiation (37V under 86 MeV·cm2/mg heavy ion irradiation) and a reverse voltage of 40V.

With prices starting at $324.55 (USD) each in 1,000-unit quantities, the ISL71590SEH is available now a 2-terminal isolated flatpack easily mountable on a system chassis or circuit board. An evaluation board, the ISL71590SEHEV1Z, also is available at a price of $232.45 (USD).