Selection and Analysis of COTS power management devices under radiation

COTS USE IN SMALL SATELLITE MISSIONS

COTS components are being increasingly selected for small satellite missions
Cost reductions are driving companies to make these selections
In many cases, this can help reduce the cost of satellite production, while still maintaining high reliability
- Automotive COTS products seem to be a good option here
COTS devices, even automotive have no radiation assurance
Power management applications are especially sensitive to radiation effects, specifically SEE
- SEL/SEB can render a power management device un-usable and building in redundant power can be challenging
- SET can potentially damage downstream devices and mitigation techniques can be limited
Radiation testing and selection can be expensive and take a significant amount of time…and in many cases, the COTS devices still do not perform

COTS COMPONENTS TESTED FOR RADIATION

List of parts tested for radiation
Total Dose testing and SEE testing (performed at Texas A&M University)
These products were selected based on fab process or radiation performance of similar parts
Even with Intersil’s background knowledge of the process and part design and experience with radiation effects , it can still be challenging to find COTS parts that have good radiation performance

Cots components

ISL85410

Serves as a cautionary tale for cots devices in space for power management
Initial radiation testing showed that the part could withstand up to 43MeV without SEL/SEB
- Vin had to be de-rated from 40V (ISL85410) to 7V abs max, with an operating max of 5.5V
Further SET testing showed significant transients at LET as low as 2.7MeV
In light of this, we had no choice but to cancel the project
In some cases, VOUT was supposed to be 2V but recovered after an ion strike where VOUT = 2.5V
- This is destructive to downstream devices

RENESAS SPACE PLASTIC PRODUCTS

SUPPORTING THE BROAD SPECTRUM OF SPACE

spectrum of space

MISSION PROFILES

Rad Tolerant Plastic

Expected Life Cycle ≤ 5 years
- - Satellites will be replaced with system upgrades
Low Earth Orbit (LEO)
- Less Total Radiation exposure and less susceptible to heavy ion strikes
  - TID Target = 30krad(Si)
  - SEE Target = LET of 43MeV∙cm2/mg
Cost Sensitive (Cost can be ~10%-20% of Class V in high volume)
- Cost reduction areas
  - Plastic package vs. hermetic
  - Radiation characterized one time up front
  - No ongoing in-line quality monitors, i.e. burn in
  - Single temperature production testing (25C)

PEMs Plastic

Expected Life Cycle > 10 years
- Satellites will be more traditional, with new weight and size requirements
Medium/Geosynchronous Earth Orbit (MEO/GEO)
- High total radiation exposure
  - TID Target = 75-100krad(Si)
  - SEE Target = LET of 86MeV∙cm2/mg
Not as cost sensitive
- Cost reductions are nice, but not a primary driver
- Board area savings are the driving factor
- Ongoing RLAT, SEE up front characterization
- 100% Burn-In and Temperature Cycle Testing
- Lot level quality monitors
- Tri-temp testing

RADIATION AND ELECTRICAL CHARACTERIZATION

TID testing done at low rate, <10mrad/sec at facility in Palm Bay, FL
Single event testing done at Texas A&M University
- SEL/SEB up to 43MeV∙cm2/mg
- SEU/SET potentially at lower LET levels
2 wafer lots electrical characterization done to full military temp range (-55C to +125C) target
- Data analysis and statistics are used to set data sheet and final test limits, final test at 25C only
For PEMs up-screened parts, the characterization process is the same as above
- Radiation performance for TID is up to 75krad
- SEL/SEB up to 86MeV cm2/mg
- Production tri-temp testing is included for higher reliability
- Production flow follows AS6294/1 standard for plastic parts in space