Speakers
Description
Summary
DPC status
Started in 2012 in the frame of an Artes 5.2 contract, the development of the Digital Programmable Controller DPC has reached major milestones in 2017. The DPC successfully passed the formal qualification process: industrial qualification as per ECSS9000.
The dilemna of the number of IOs
Micro-controller are intended to be used in a very board range of applications & use cases. For terrestrial applications, semiconductor manufacturers are proposing many variants of their micro-controllers with among other small, medium or large number of analogue and digital IOs. This is the ideal situation that also corresponds to needs in space applications. The problem is that space qualification of a component is not only linked to die but also to package. Hence this would require the 3 qualifications of the 3 component variants. This clearly not affordable. For DPC, the choice was made of a large package offering more than 120 IOs.
A good alternative to reduce the component footprint while maintaining large pin count is CCGA. Back five years ago collumn grid package was only available from US suppliers, hence adding export control issues to a design that had intentionnally be made completely US free. So that the bulky CQFP 256 package was the only option affordable at low risk.
Nowadays, the situation has improved columns are available from Eu source. Nevertheless this technology remains used for very large pin-count components like big CPU, ASIC or FPGA. Mostly the reason is cost which remains well above a “simple” CQFP.
Cost is the other major factor that limits the massive introduction of micro-controllers. When a designer has to optimize the total cost of the bill of material of an equipment, the natural trend is to concentrate a maximum of control functions into a single component.
A breakthrough
A breakthrough ( BGA non-hermetic ) has changed this paradigm. Low cost but non-hermetic packaging in the far east is the answer. TASB has designed in cooperation with IMEC-services (IC-Link) a BGA variant of the DPC. This component is assembled on an full automotive assembly line (monthly producing millions of pieces) therefore offering a well mastered & reproducible process.
Thanks to the nature of the base substrate (=FR4 instead of ceramic like in CCGA) the thermal expansion coefficient of the application PCB is matching very well. This practically means that standard low cost balls can be used for assembly instead of (space specific) columns.
The result is a component that occupies 6x less area on the PCB with almost an order of magnitude difference in recurrent cost (this heavily depends on the requested test coverage). Consequence: designers are no longer freigthened by the use of several DPC in a equipment. IO are missing ? Use 2 µC. Processing power is too low ? Use 2 µC. Even memory is missing for an given application ? Split it into 2 and spread it over 2 µC…
This breakthrough also makes the DPC affordable to be used in CubeSat both in term of size & cost. The University of Liège had successfully developed & launched on 26 Apr 2016 of the OUFTI-1 educational 1-U CubeSat, with an amateur-radio D-STAR repeater as its primary mission. In its OUFTI-2 project, a DPC with BGA package will be used as OBC leaveraging on the full radhard properties of the DPC. Hence delivering a trustable OBC control system.
