Thread: Tants
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Old 15th Feb 2018, 11:27 am   #12
Craig Sawyers
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Join Date: Nov 2010
Location: Oxford, UK.
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Default Re: Tants

The main problem is that the spec sheet for the tantalum beads back in the early 80's suggested that 6V ones should be used to decouple 5V rails, 16V ones on 15V rails etc. That is why they were made with such strange voltages. That is now known to be an invitation to disaster. Current guidelines is that they should have at least 30% and preferably 50% higher voltage rating than the rail voltage. So for example 8V on 5V rails, 20V on 15V rails etc.

Or just use low ESR electrolytic. Which is what Tektronix did on later versions of equipment that previously had the exploding tant syndrome.

But when they are used in signal level circuitry they are just fine. It is just applications where they get surge voltages and currents (ie power rails) that they are a problem.

Craig
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