As the NewSpace industry continues to evolve, many missions are turning to non-space-grade power solutions to meet tighter budgets and timelines. However, this shift introduces critical risks that can jeopardize reliability and mission success. In our recent webinar, Powering NewSpace Missions: Navigating the Cost vs. Reliability Challenge, VPT’s Director of Engineering explored how we strategically balance cost and performance in the VSC Series of DC-DC converters and EMI filters, designed specifically for low Earth orbit (LEO) applications.
As a follow-up, we've compiled and answered the top audience questions raised during the event.
If you missed the webinar, you can watch the full recording here.
Programs, Missions, and Heritage
1.) Do you have a satellite heritage for VSC Series? Please name a few. What are the failure needs?
The VSC Series is a new product offering, so the launches to date are limited, but VSC products have been in orbit for more than a year now. Further, VPT doesn’t connect specific programs to specific products as this information is proprietary to the customers.
2.) What would you recommend for MEO and GEO Missions? VSC or SVL or SVR Series products?
It depends on the specific mission profile, but SVL or SVR products would probably be most appropriate for these orbits. Learn more about VPT’s space-grade series.
3.) I have seen LEO missions that simply cannot fail. Do you see the SVL or SVR Series products as more applicable than the VSC for these types of "can't afford to fail" national security missions?
Yes. You can learn more about the SVL and SVR Series or our other space-grade series here.
4.) What about Launch Vehicles? Is the VSC part applicable for these types of missions, or would SVL/SVR be a better match?
The VSC Series can be used for launch vehicles. The idea behind VPT’s product lines is to be able to offer an appropriate grade and radiation tolerance level for any space mission. It is ultimately the customer's responsibility to select the proper grade of product for their specific mission.
Testing, Qualification, and Screening
1.) Are these parts molded or lidded/filled?
The VSC Series is molded.
2.) Can I learn what is the test level for random vibration in G rms?
Random Vibration: Qualified to MIL-STD-883, Method 2026, Table I, Condition F.
3.) Does the VSC Series go through any shock and vibration testing?
Mechanical Shock: Qualified to MIL-STD-883, Method 2002, Condition A.
4.) Are the radiation test and temperature test — simultaneous or separate?
They are separate.
5.) Do you submit the VSC products to QCI (Quality Conformance Inspection)?
We have an internal quality control procedure.
6.) Do you have pre-cap inspection for VSC Series?
VPT does not offer customer pre-cap or customer final inspection of the VSC products. VPT does perform its own pre-cap and final inspection of our products as part of the standard manufacturing process.
7.) Has VPT considered including the HAST test?
We have a full qualification plan that includes shock vibration, temperature cycling, life test and humidity.
8.) Is there a plan to qualify the ES+ as 38534 non-hermetic Class L&F?
Not at this time.
9.) What is the roadmap — do you foresee other DC-DC topologies in the future, like boost converters?
VPT has new POL converters and higher output power models planned for the VSC line. We are also developing a triple output model that is a little further out. Currently, there are not any boost converters on our product roadmap. If there is a specific application for a boost converter do not hesitate to contact VPT to see if the application business case could support development of such a product for your application.
10.) Do the VSC Series regulators have a monotonic voltage rise during turn-on?
Yes, along with all of our products.
11.) For these VSC parts, is there a "subgroup" that receives testing over a higher number of temperature cycles?
No currently, we only have one screening option for the VSC Series.
Reliability, Life, and Failure
1.) Are you going to talk about the expected reliability of these devices?
We use MIL-HDK-217 for our MTBF calculations. The report is available for purchase. If you’d like to learn more, please contact our sales team.
2.) What is the life expectancy for these devices?
The MTBF can be found in the datasheet and the report can be purchased. If you’d like to learn more about the MTBF report, please contact our sales team.
3.) How did you decide 96 hours was sufficient burn-in to eliminate infant mortality?
This is equivalent to our ES screening from the thick film hybrids and there is a significant roll off infant mortality after 96 hours. VPT does not see many failures after the first 96 hours of burn in. We believe this is the best compromise of cost vs reliability for a NewSpace product series.
4.) Have you tested these parts to failure to determine activation energy?
For a single event we test up to 48 MeV for failures.
5.) Please describe how VPT decided VSC is a reliable product: what kind of testing and sample sizes were used, and what were the results (e.g., FIT rate, MTTF)?
MTBF reports are available for purchase. We also have a qualification report that highlights the testing we have performed. The radiation test report shows how the part will perform in a radiation environment.
6.) What manufacturing controls does VPT have to avoid workmanship and manufacturing issues?
This is an internal process. VPT has a long and successful history of optimizing our manufacturing quality and has 10’s of thousands of products in space today from LEO orbits to the surface of Mars. The manufacturing process of the VSC Series utilizes these same tried and true manufacturing, inspection and test processes adapted to the VSC Series but based on our thick film hybrids manufactured to comply with MIL-STD-38534.
7.) What is the life guarantee on VSC products at temperature extremes and LEO radiation?
All our limits in the datasheet are for post radiation performance. The MTBF report can be run at different case temperature than the standard 50°C in the datasheet if requested.
8.) To what extent is lifetime just being in space (e.g., TID) and to what extent is it operational time if a subsystem is operating intermittently?
The difference will be very small insignificant if the temperature during operation is not much larger than in intermittent operation.
Product Comparisons & Class Definitions
1.) How did you define the minimum screening needed for this ES+ component?
We tried to keep the essential screening steps for the lowest possible cost and time.
2.) What is the reliability of the ES+ compared to the K version?
The Class K screening is much more reliable, however the part is significantly more expensive. The ES+ is not meant to compete with a Class K hybrid.
3.) In electrical point of view (specification, components...), is there any difference between ES+ and qualified space version?
Yes, the hybrid will have a perform differently than the VSC Series. Our Class H and K products are different from the VSC Series. Learn more about our different space-qualified series.
4.) You've mostly compared Class ES and Class K — what about Class H? Is Class H mid-way, closer to K, or to ES?
The table below summarizes all of the hybrid screening levels. You can review this in more detail here.
5.) Using NEPP (e.g. NASA-STD-8739.11 or EEE-INST-002), what level does VSC (Class ES) meet?
The VSC products are upscreened commercial parts. This is the way we can offer it for a low price. VPT does offer a large number of parts that have higher screening levels.
Radiation & Screening for COTS
1.) Do you contemplate radiation tests (SEE/TID) as part of lot screening to ensure foundry process changes haven't impacted tolerance?
We test the overall part once a year for both SEE and TID to look for component variation.
2.) For COTS (no traceability in foundry process), do you think this type of radiation screening is necessary?
We test all of the active components and test the overall converter once a year to look for any manufacturing changes.
Cost, Lead Time, and Supply Chain
1.) What is the cost and lead time difference for various product series?
Please contact VPT or your local distributor for a precise quote.
2.) What is the relative cost difference between a VSC module and a comparable thick-film hybrid module?
The VSC is considerably less expensive, but please contact VPT or your local distributor for a quote.
3.) How do you guarantee continued supply of your BOM parts after qualification?
We guarantee that the parts purchased meet the published specifications at the time of purchase. Should a component be obsolete by the manufacturer, we will either find a qualified equivalent or redesign and requalify as necessary depending on our options.
4.) When a customer of mine requires DPA it can add a lot to the cost. What info can you give to reduce the perceived need for DPA?
DPA is not available on VSC products.
Functionality & Features
1.) Do you plan to offer a VSC converter over 100W?
We currently do not have any parts on the roadmap. The VSC100-2800S and VSC100-2800D do have a share pin that allows multiple converters to be paralleled to increase the total power.
2.) Any plans to develop a flanged version of VSC to enable footprint compatibility with SV parts?
Not at this time.
3.) Can you connect VSC modules in parallel and/or series?
All of the isolated converters can have the outputs in series. The VSC100-2800S and VSC100-2800D have a share pin that allows them to operate in parallel. Read our User Guide for VPT DC-DC Converters to learn more about product functions, features, best practices and more.
4.) Do you have SPICE models for the VSC product line?
Not at this time.
5.) Any plans for a current limiter in the VSC Series?
This is currently not on the roadmap. The VSC designs utilize a constant current limit for the output current for short circuit protection.
6.) Is there a similar series of parts for 120VDC bus conversion?
VPT’s only 120V input part is the SGRB.
7.) Do you have reference designs for the POL powering FPGAs?
Not at this time.
System-Level Performance & Analysis
1.) Converters are closed-loop systems — how does someone assess the converter's system performance via analysis without full testing?
VPT recommends testing.
Product Roadmap and Future Plans
1.) I heard you were considering a VSC-like part with the same footprint as H or K — true?
This is not currently on the roadmap. We offer a full line of Class H and K products already.
2.) What is the roadmap, do you foresee other DC-DC topologies in the future, like boost converters?
We are expanding the VSC line with POL models and higher output power modules. A triple output is under development as well. Currently, there are no boost converters planned.
