Radiation tolerant eight-channel source driver for space programmes

Offered in two package types with various screening options, the device has met the key requirements to operate in space environments, as the qualifications are mandatory for design-ins for space programmes and for manufacturers to be listed on the QML by the DLA.

“Successfully achieving these qualifications is vital to securing design-ins in satellite programmes requiring the highest quality and reliability performance,” said Dorian Johnson, Microsemi’s High Reliability Product Marketing Manager. 

“Obtaining QML status not only demonstrates Microsemi’s continued commitment to supplying integrated space solutions, but gives our customers the added assurance that our radiation-tolerant AAHS298B source driver can meet the demanding requirements of the DLA while offering the ability to use the device in conjunction with our LX7730 telemetry controller, LX7720 motor controller and LX7710 diode array devices.”

Microsemi’s high performance AAHS298B source driver provides an interface between spacecraft bus electronics and other subsystems, with the highest output source current for space applications requiring radiation tolerance. Command signal outputs from the spacecraft’s digital control electronics are typically TTL (5V), CMOS (3V) and high-level (12V) logic and are not directly compatible with users’ command input requirements.

These user requirements occur in payload, power, thermal and housekeeping subsystems and range between 14-45V. The AAHS298B is an interface between these systems, providing a continuous 700mA current to switched high side-drivers on the output.

The integration of eight non-inverting high side channels gives satellite designers reduced weight, resulting in smaller board space, and higher reliability as compared to discrete implementations. As many satellite manufacturers and projects require the DLA QML certifications and listings as assurance the product meets Military Performance Specification (MIL-PRF) requirements, the AAHS298B meets these standards as part of the company’s growing portfolio of mixed signal Integrated Circuits (ICs) for demanding space applications.

“Increasing requirements for higher output currents combined with demands for weight and board space reductions were compelling reasons to initially investigate Microsemi’s AAHS298B source driver for our designs,” said Glenn Lommasson, Vice President of Design & Development Engineering Services (DDES) Corp.

“In addition, the presence of the internal clamp diode in the driver output allowed a much more efficient method for implementing transient protection during inductive kickback events, which reduced the number of clamp diodes needed in other solutions. The recent device qualification and SMD listing as a QML-V device was also a very important element for us to baseline this part as more programmes are mandating Technical Operating Report (TOR) guidelines for parts quality, DLA certification and radiation assurance.”

According to Euroconsult's 2017 report titled: “Satellites to Be Built & Launched by 2026,” 300 satellites with a launch mass over 50kg will be launched on average each year by 2026 for government agencies and commercial organisations worldwide. This represents an average of $30bn per year for the space industry to build and launch them, representing a 25% increase over the past decade.

Microsemi’s expertise in mixed signal space solutions comes from over 20 years of custom and standard design and manufacturing experience in providing its customers with innovative space system solutions. As satellite manufacturers typically require Class V and Q qualifications, the designations provide customers with an added level of assurance that the radiation-tolerant AAHS298B eight-channel source driver has met the stringent industry standards.

The QML qualification achievement allows designers across the entire spectrum of space designs, from low cost commercial and scientific applications to human rated and top priority government systems, to use the parts without cumbersome part selection justifications or source control drawings.

Microsemi’s AAHS298B source driver is well suited for applications including command and data handling power subsystems, spacecraft control electronics attitude control, relay/solenoid drivers, as well as stepper and/or servo motor drivers.

Key features of the device include:

• 700mA output source current
• Zero quiescent off-current
• Full channel isolation to prevent fault propagation
• Internal ground clamp diodes
• 75V output breakdown voltage
• TTL, 5V and 12V Logic-compatible
• Internal thermal shutdown to protect against over-current and soft-start occurrences
• Radiation-tolerant to 100kRad (Si) total dose, 50kRad (Si) enhanced low dose radiation sensitivity (ELDRS)
• Temperature range of -55°C to 125°C
• Available in 20-pin ceramic Small Outline Integrated Circuit (SOIC) with formed and flat leads
• QML listed with SMD 5962-15231
• Four SMDs covering Q and V screening flows for two package options