Low-leakage tantalum capacitors for detonating explosives

Vishay has introduced a series of surface-mount solid moulded tantalum chip capacitors specifically for electronic detonation systems “combining a robust mechanical design with low leakage current and stringent testing specifications”, according to the company. “Each part is 100% surge current tested using standard screening methods, and undergoes two additional screenings for key electrical characteristics to eliminate lot-to-lot variations.”

Called TX3, maximum dc leakage within the family follows the formula 0.005CV at 25°C, so 1.76μA for the 22μF 16V part, for example. This can be up to 10x higher at +85°C and up to 12x higher at +125°C – operating temperature range is from -55 to +125°C.

Shock and vibration resilience to MIL-STD-202 is 100g and 20g respectively.

They come in only two case sizes: 3.5 x 2.8 x 1.9mm ‘B’ (EIA 3528-21) or 6 x 3.2 x 2.5mm ‘C’ (EIA 6032-28).

Available values span 10 to 100µF, with +85°C voltage ratings of 16, 20 or 25Vdc – not all capacities are available at each voltage.

At +125°C, these standard voltage ratings drop to 10, 13 or 17Vdc respectively, and further voltage derating, by approximately half (see data sheet), is required if the capacitors are connected directly to power trails.

ESR (effective series resistance) values at +25°C span 700mΩ to 2.3Ω across the range, and ripple current rating peaks at 438mA among the parts.

Use is foreseen storing ignition energy in remote detonation systems for mining and demolition.

Find the TX product page here and its data sheet here