I have seen these devices fail shorted due to "inadvertant" reverse installation and do an amzing amount of damage even in 5V circuits. Upon reverse installation, the capacitors fail shorted when subjected to very low level spikes. In circuits where there is no current limiting or the level is quite high these capacitors will continue to conduct and spread heat to surrounding areas. I have tested very small surface mount packages that still conducted (reverse installed) at several amperes. I would recommend current limiting or in-line fusing. As an interesting side note I contacted several manufacturers of tantalums and they could give me little or no information on MTBF or failure modes.
Darrell Locke Advanced Input Devices ---------- From: Brumbaugh, David To: 'emc-pstc' Subject: Tantalum Capacitors List-Post: [email protected] Date: Tuesday, June 30, 1998 8:46AM Can anyone tell me if there are any drawbacks in using tantalum capacitors in dc power supply filters? My recollection is that they can "pop" if the voltage polarity is reversed, or if there are large negative voltage swings during transients. TIA, David Brumbaugh The BOEING Company Information, Space & Defense Systems Electromagnetic Effects M/C 8H-11 POB 3999 Seattle, WA 98124-2499 Phone: Kent Space Center (253) 773-3733
