Microchip Builds Radiation-tolerant LDO Regulator for LEO Satellites

January 23, 2023 by Aaron Carman

Targeting low-earth orbit satellites, Microchip has released its first radiation-tolerant power device.

Hoping to earn a spot among low-earth orbit (LEO) satellite systems, Microchip Technology announced its newest radiation-tolerant device: the MIC69303RT low-dropout (LDO) regulator. As LEO satellites become more commonplace, the addition of the new LDO offers a compatible, reliable solution for powering Microchip's other radiation-tolerant offerings.

Power supply is critical in any electronic system. But in a space-centric application, variations in power integrity can cascade into a full system shutdown.



While the latest offering from Microchip is purpose-built for space applications, it also provides designers with a familiar form factor for terrestrial devices. Image used courtesy of Microchip


Despite the device's extensive qualifications and enhanced tolerances, the new LDO from Microchip is engineered to be designer friendly. This article provides background information on LEO missions and their unique requirements and summarizes the key specifications of the MIC69303R to help designers understand what Microchip’s newest LDO can provide them.


A Harsh Environment for Electronics

Operating within 1,200 miles (2,000 km) of the Earth’s surface, LEO satellites have quickly become a key interest in the engineering world—stretching beyond even the commercial sector, with DARPA hoping to develop an LEO translator. Despite their relatively small orbit radius, LEO satellites are still subject to conditions unlike those on the planet's surface, with radiation being a major concern for designers.

As electronics ascend into higher operating altitudes, the atmosphere's protection fades away and more cosmic radiation reaches sensitive devices. This radiation exposure can cause catastrophic failure, as was the case in last year’s SpaceX satellite losses


A typical application circuit for the MIC69303RT

A typical application circuit for the MIC69303RT highlights the ease with which the LDO can be deployed in an LEO system while also providing the required radiation tolerance. Image used courtesy of Microchip (Datasheet linked for larger image)


To prevent these costly malfunctions, reliable radiation-tolerant electronics are an essential prerequisite for all subsystems in LEO satellites. This is especially true for power electronics, because the effects of operating errors can be felt across the entire payload.


Robust Performance in a Familiar Form Factor

Making its entry as Microchip’s first radiation-tolerant power device, the MIC69303RT (datasheet linked) offers designers two package options depending on their specific needs. The first of these uses a hermetic, ceramic 10-lead package, increasing reliability and resilience against extreme conditions and following MIL Class Q or V requirements.

The alternative uses a more familiar eight-lead plastic package that follows the AEC-Q100 automotive requirements (additional tests are needed to determine its suitability for space). Both form factors report a dropout voltage of less than 500 mV across the entire operating range, with a maximum output current of 3 A and a minimum output voltage of 0.5 V.


Line and load transients for new Microchip LDO

The line and load transients illustrate the regulator's efficient regulation of the output voltage. As the input voltage and output drastically change, the output voltage experiences only minor transients. Image used courtesy of Microchip


The MIC69303RT may be used as a companion device for Microchip’s radiation-tolerant microcontrollers and FPGAs and, as such, demonstrate resilience against both line and load transients created by digital circuits. The reduction in transient noise is intended to improve the sensitivity of RF circuits and benefit other high-performance applications where a stable output voltage is essential.


Standing Up Against Cosmic Rays

Access to Microchip’s new LDO is currently limited to sampling on request. In addition to the LDO, Microchip provides an evaluation board that features the plastic-packaged version of the MIC69303RT.

While radiation tolerance certainly improves the device’s chances of survival, it is not a one-size-fits-all solution for every space-based application. The LDO is rated up to 50 Krad of absorbed dose and includes single event effect (SEE) protection. Beyond these limits, the device may fail.

The new commercial power device uses familiar plastic packaging, making it easier and faster for designers to develop prototypes and continue the momentum in the LEO community.