In Mark Doyle's, British Broadcasting Corporation Correspondent, blog, Mark posted an entry relevant to anyone designing Embedded Systems power supplies. Mark is reporting that "The President of Congo, Joseph Kabila, recently ordered a ban on mining in the area". The a area he is referring to are the Gold and more importantly to us Tantalum mines in that area.
Mark's online summary does not mention it, however on the actual BBC report I heard on the radio yesterday morning, they specifically mentioned Tantalum "used in mobile phones". Seems the Bad Guys were smuggling Tantalum, but as no one knows what that is, so they call it Gold and "other minerals". The on air report also said this whole episode had the good makings for a Spy Movie, complete with the take down of the Bad Guys on the airport tarmac.
Tantalum Capacitors are used as part of the power supply regulators in many devices. They have several unique properties, such high capacitance to volume ratio, an Equivalent Series Resistance (ESR) that falls within the Goldilocks Zone of not to low and not to high, to prevent the regulators from oscillating etc.
Newer regulators are stable with Ceramic Capacitors. The problem is supporting the legacy designs that can not be changed due to the acronym agency paper work. Pick the one of your choice: FDA, MSHA, FCC, UL etc... :-(