Concerned about scarce supplies and high prices of tantalum powder, capacitor suppliers are ramping production of niobium capacitors as an alternative.
Several companies expect to be manufacturing niobium capacitors in volume by early next year, and many are already sampling the devices or plan to soon.
Vishay Intertechnology Inc. has begun offering samples of niobium capacitors with working voltages of 4, 6.3, and 10VDC and capacitance values of 4.7 to 470 microfarads. Vishay expects volume production by March 2002, according to Glyndwr Smith, senior vice president and assistant to the chief executive of the Malvern, Pa., company.
Japan's NEC Corp. will start sampling the first in a line of niobium capacitors in August. The 2.5V, 220??F part will initially be the same price as a tantalum capacitor but will come down after production volumes ramp up early next year, an NEC spokesman said.
EPCOS AG, Munich, Germany, could not be reached for comment, but is reportedly also shipping sample niobium capacitors and will be in full production by year's end, according to a released statement.
Niobium capacitors have been in development for several years. However, component makers have stepped up their efforts in the past year due to concerns that supplies of coltan, the ore processed into tantalum powder, won't be sufficient to meet future needs for tantalum capacitors, a key component in portable products such as wireless phones, Vishay's Smith said.
Last year's strong demand caused lead times for tantalum capacitors to stretch to several months as suppliers scrambled to obtain tantalum powder, passing escalating materials prices to OEMs along the way.
Suppliers also worry that some tantalum powder originates in ore obtained through illegal coltan mining and trading conducted by warring factions in the Republic of Congo.
Niobium is far more abundant than tantalum. The U.S. Geological Survey in Reston, Va., estimated the world's reserves of niobium, also known as columbium, at 5.5 million tons in 2000, compared with 60,000 tons of tantalum.
Because it is more abundant, niobium costs at least 10 times less than tantalum, according to several sources of current metal prices. This should translate into lower production costs for niobium capacitors, suppliers said.
The new alternative has both performance advantages and drawbacks.
Niobium capacitors can be made in the same form factor as conventional tantalum chip capacitors and in many cases can be built on the same production lines, the NEC spokesman said.
Niobium provides a higher dielectric constant than tantalum, thus allowing the capacitors to be made smaller or incorporate a higher capacitance rating in the same-size chip package, EPCOS said.
Other suppliers acknowledged that niobium capacitors fall short of tantalum types in leakage current and operating temperature stability.
However, those limitations would not hinder the capacitors in low-voltage applications in which tantalums now get a lot of use, according to Chris Reynolds, applications manager at AVX Corp., Myrtle Beach, S.C. AVX plans to sample niobium capacitors by year's end