By Stephen Armstrong is US-based technical writer

Military demand for high quality, high-voltage multi-layer ceramic capacitors (MLCCs) has been hit hard by a shift in production by the world’s largest MLCC manufacturers who are focusing on a seemingly insatiable demand for smaller, lower voltage and, in some way, lower-performance MLCCs. This demand has been fueled by the global growth of 5G networks and continued advancements in smart phones and mobile devices who are consuming significantly more MLCCs per device.

As the principal manufacturers pivot away from the larger, high-voltage, high-Q (High Quality) MLCCs used by the military, OEMs are experiencing significant delays in MLCCs of up to six months. The extent of the supply shortage jeopardises product release schedules and potentially even military readiness.

“It is a pretty massive carrot that is hanging in front of the major MLCC manufacturers,” said Scott Horton, vice president at Johanson Technology, a 40-year provider of high-voltage ceramic multi-layer capacitors based in Camarillo, California. “When you consider that a high-end smartphone today can require substantially more MLCCs in a single device as compared to a similar phone only a few years ago, the current demand for smaller, lower-power MLCCs is like nothing the market has seen before.”

As a result of a slowdown in consumer demand for capacitors in 2019, many OEMs and distributors were left holding surplus inventory. As a result, these same OEMs and distributors were hesitant to order additional inventory in 2020. Now, as the market ramps up, so does the demand for MLCCs, despite very low capacitor inventory. This further exacerbates the shortage of larger, high-voltage, high-Q MLCCs, since some manufacturers have focused production on smaller/lower-voltage MLCCs during this time. Now both ends of the market are scrambling to re-stock including the large electronics distributors.

“There is a ripple effect to the military market sector that is not really fully understood,” said Horton. “Although a shortage of electronic products used to manufacture consumer products like smartphones and automobiles would be national news, the lack of supply of larger, higher-voltage MLCCs for military applications are typically under-reported. However, it will continue to squeeze business customers and eventually end users until it is resolved.”

Multi-layer ceramic components

MLCCs consist of laminated layers of specially-formulated ceramic dielectric materials interspersed with a metal electrode system. The layered formation is then fired at high temperature to produce a sintered and volumetrically-efficient capacitance device. A conductive termination barrier system is integrated on the exposed ends of the chip to complete the connection.

Capacitance is primarily determined by three factors: the k of the ceramic materials, the thickness of the dielectric layers, the overlap area and the number of the electrodes. A capacitor with a given dielectric constant can have more layers and wider spacing between electrodes or fewer layers and closer spacing to achieve the same capacitance.

Military consumers of MLCCs depend on high-voltage and high-Q capacitors for power supplies, amplifiers, lasers and many other specialised applications. In circuits with higher currents, higher-Q MLCCs are preferred to reduce self-heating, where the Q factor represents the efficiency of a capacitor’s rate of energy loss. High-Q capacitors lose less energy reducing the need to dissipate or cool the heat which protects the board from damage and performance loss in sensitive and high liability applications.

Not all MLCCs are created equal, however, even among the high-performance MLCCs, yet ensuring a consistent level of performance is critical for the high reliability applications required by the military.

“If a MLCC manufacturer is not tightly controlling the layer count, they might be providing ten-layer parts in one batch and then later deliver 17-layer parts in a subsequent one,” explains Horton. “These two parts will not perform the same at high frequencies.”

US supply is ramping up

Domestic sources of MLCCs needed in military applications have been ramping up their capacity. Increased domestic MLCC supply means customers will not need to delay the build and shipments of their products because of a capacitor delay.

Drawing upon its focus on high-Q and high-voltage MLCCs, Johanson, for example, has expanded its capacity to fill some of the supply void caused by the shift in market focus to smaller capacitors.

“We’ve been investing in expanding our capacity for several years now through a modernisation of our production facility and the opening of a second production line that will essentially double our MLCC output. We can take that even higher with more production shifts” says Horton.

At the time of the preparation of this article, Johanson is quoting large-size, high-voltage MLCC order fulfillment times at 10 weeks.

“There’s just no reason to move away from ceramic for your high-voltage, high-quality applications,” said Johanson’s Horton. “There is now a growing domestic MLCC supply available to meet our domestic (US) needs.”

Shifts in supply and demand within the overall MLCC market, which is estimated to grow to a $12bn market by 2025, have caused critical supply shortages for military customers who require a higher-quality, larger-format multi-layer ceramic capacitor. As the largest MLCC manufacturers continue to compete for the demand of the MLCCs used by sectors like telecom, smartphones and mobile devices, new US supply sources are stepping in to meet the need for a reliable and timely supply of high performance MLCCs.