Current sources simplify satellite subsystem design, claims Renesas

The radiation-hardened precision current sources, the ISL70591SEH and ISL70592SEH, are the first current source ICs in Renesas Electronics’ line of space products. They are, says the company, suitable for telemetry, tracking and command, attitude and orbital control, and electrical power subsystem applications.

The ISL70591SEH and ISL70592SEH current sources provide current excitation to the 300+ resistive sensors that monitor the health of a satellite’s subsystems. 

The ISL70591SEH and ISL70592SEH are supplied in four-lead ceramic flatpack packages and provide 100microA and 1mA of output current, respectively. The current sources offer a smaller footprint than competitive devices, claims Renesas, and replace the discrete solutions available today that typically require three to five components. The smaller package size boosts reliability by placing the excitation source closer to the sensor, adds the company. The current source ICs also reduce system errors by delivering low noise for higher accuracy over temperature and radiation. The high output impedance of the ISL70591SEH and ISL70592SEH rejects voltage variations on the supply line, and lets designers parallel multiple current sources if they need higher current.

The ISL70591SEH and ISL70592SEH use Renesas’ proprietary silicon on insulator (SoI) process, which provides single event latch-up (SEL) and single event burn-out (SEB) robustness in heavy ion environments. Both devices are radiation assurance tested to 100krad (Si) at high dose rate and 75krad(Si) at low dose rate. The floating design lets users create a current source or sink with no ground connection.

The ISL70591SEH and ISL70592SEH can be combined with the Renesas ISL71590SEH temperature sensor, ISL71840SEH 16-channel multiplexer, ISL70517SEH instrumentation amplifier, ISL71090SEH25 low-noise voltage reference, ISL70001ASEH 6.0A synchronous buck regulator, and ISL72026SEH 3.3V CAN transceiver to form an analogue signal chain that includes power management and communications devices.

The ISL70591SEH and ISL70592SEH radiation-hardened precision current sources are available now in four-lead CDFP packages or in die form.