Silicon trench capacitors save space in wearables

Rohm has developed its first silicon capacitors, the 400 x 200 x 185μm ( 01005, 0402 metric) BTD1RVFL series which covers 100pF to 1nF.

ROHM BTD1RVFL silicon capacitors

“The mounting area is reduced by approximately 55% over general 0201 [0603 metric] products to just 0.08mm2.” according to the company. “Moreover, a built-in transient voltage suppressor protection element ensures high ESD resistance.”

They are rated at 3.6V, with the internal bi-directional TVS breaking down between 8.2 and 9.2V.


Rohm silicon trench capacitor

Trenching is used to increase capacitance per unit area, and, being made from silicon, the devices step outside the usual three-character ceramic capacitor temperature coefficient labelling system. Operation is over -55 to +150°C with a ±250ppm/°C coefficient. Capacitance tolerance is ±15%.


Rohm silicon capacitor geometry“Miniaturisation technology allows processing in 1µm increments that eliminates chipping during external formation and improves dimensional tolerances within ±10µm,” said the company. “This small variation in product size enables mounting with a narrower distance between adjacent components. At the same time, the backside electrode used for bonding to the substrate has been expanded to the periphery of the package to improve mounting strength.” Total pad area for bonding is ~0.032mm2.

Two parts are available, with five more following:

BTD1RVFL102 1,000pF
BTD1RVFL681* 680pF
BTD1RVFL471 470pF
BTD1RVFL331* 330pF
BTD1RVFL221* 220pF
BTD1RVFL151* 150pF
BTD1RVFL101* 100pF

*under development

Applications are foreseen in smartphones and wearables.

A second series, scheduled for introduction next year, is being developed with improved high-frequency characteristics (lower ESR and lower loss) for RF applications, and then a higher voltage third generation is planned for industrial and automotive use in 2026.


Comments

3 comments

  1. £5 each at Mouser ! Obviously a samples price (which should be free guys !) but don’t think I’ll be designing these in quite yet.

  2. It is nice to see the flat capacitance vs. DC bias plot, but I would also like to se a |Z| vs frequency plot. I am not sure how to use the built-in TVS.

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