Top 10 Things to Consider Before Replacing MLCCs

August 24, 2018
By Rob O'Connor

Don't Let MLCC Shortages Let You Go Line Down!

Based on what the industry experts are reporting, the current MLCC shortage is expected to last for quite some time. The shortage is predicted to last a minimum of 2 years and possibly longer, which currently makes it a good time to consider the alternatives to MLCCs. The extremely long MLCC lead-times will keep many production lines down, so why not start your MLCC design replacement journey now? There are many replacement options for review, Panasonic’s Capacitor product line includes a wide variety of technologies that are recommended alternatives to MLCCs. But before formulating your potential design replacement plan for MLCCs, there are several things that need to be considered specific to your applications design.

1. VOLTAGE

Knowing the maximum operating voltage of the system you are considering MLCC alternatives for is critical. All Capacitor technologies have limits to their maximum operating voltage and to the momentary overvoltage that they’re able to withstand. Designers need to be cognizant of these limitations and utilize the Capacitor families that can resist the maximum applied voltage and any possible transient overvoltage. Ignoring this may cause a shortened system life and the possibility of catastrophic failure.

2. REQUIRED CAPACITANCE

The total capacitance necessary in a given circuit often requires the use of multiple capacitors in parallel. Circuits utilizing MLCCs are impacted greatly by the DC Bias effect which reduces the effective capacitance as the applied voltage increases. Designers must calculate the effective capacitance and use an appropriately sized Capacitor. Fortunately, in most applications the number and the amount of rated capacitance is much lower since Polymer and Film Capacitor alternatives are not affected by the DC Bias effect.

3. RIPPLE CURRENT

Excessive ripple current beyond the rating of any Capacitor will lead to undesirable heating. This can have a detrimental effect on its life and cause premature failure. To ensure the reliability in your design, the MLCC alternative must be selected properly to handle the systems total ripple current at the switching frequency.

4. OPERATING FREQUENCY

MLCCs tend to have excellent high frequency characteristics due to their construction, giving them very low ESR and low ESL. Existing designs where the switching frequency approaches or exceeds 1 MHz would require Capacitors designed for high operating frequencies. Capacitors such as the SP-Cap™ GX Series includes a third terminal to minimize ESL and provide ultra-low ESR. This combination enables the Polymer Aluminum Capacitor option to perform at high frequencies.

5. OPERATING TEMPERATURE

An applications operating temperature, especially the maximum operating temperature, has a direct impact on the choice of Capacitor selected to replace MLCCs. Some technologies such as the new ZF Series Hybrid Capacitors are usable up to 150oC with excellent life and performance.

6. MAXIMUM HEIGHT

Height limitations within your design will impact which MLCC alternatives to consider. If faced with height restrictions, plastic packed devices such as SP-Cap™, POSCAP™ or SMD Film Capacitors should be considered due to their low profiles. If height is not limited but the system voltage is over 35VDC, there are rolled type Capacitor options from the OS-CON™ and Hybrid families that are suggested.

7. AVAILABLE PCB REAL ESTATE

In many designs there is a limit to the size of the PC Board which limits the available room for components. Fortunately, Alternative Capacitor technologies can save substantial space when compared to the amount of space MLCCs would typically use. In some cases, using SP-Cap™ as an MLCC Alternative offered a space savings of up to 70%.

8. LIFE EXPECTANCY

Capacitors play a critical role in the overall life of a design. When considering alternatives to MLCCs, it is important to carefully choose the right Capacitor to meet the desired life expectancy of your design. Often, maximum temperature derating can lead to extremely long life. In the case of Polymer Capacitors, estimated life increases by a factor of 10 for every 20°C drop in maximum temperature below the rated maximum temperature. For example, OS-CON™ and POSCAP™ Capacitor options can offer endurance of 2,000h at 105°C. With maximum temperature derating life can be extended to 20,000h at 85°C and 200,000h at 65°C.

9. TOTAL SOLUTION COST

While the individual piece price of a Panasonic MLCC alternative suggestion is generally greater than that of individual MLCCs, the total solution cost is most often substantially less. This savings is due to the reduction of the total amount of Capacitors used for a given design. Some examples demonstrate as many as 12 MLCCs replaced by 1 SP-Cap™, producing tremendous cost reduction.

10. MANUFACTURING ISSUES

MLCCs are considered some of the most robust electronic components. Their handling characteristics such as storage, soldering and washing is very different than that of other alternative technologies. To successfully utilize the existing MLCC alternatives, manufacturing processes must be adjusted to meet certain requirements. Detailed information is available in the Application Guidelines for each of Panasonic’s MLCC alternative options and should be consulted during the design process.

Panasonic has a total of 5 MLCC alternative options which include POSCAP™, OS-CON™, SP-Cap™, Hybrid and Film Capacitors that can rescue your design from the current MLCC market situation. Most of these options are not drop-in replacements and would require some design effort. Specifically, Panasonic’s Polymer Capacitors which require more care and manufacturing engineers would need to be involved for redesign adjustments.

So, what’s next? The next step to consider would be to speak to a Panasonic MLCC Replacement Specialist for additional support in applying Panasonic’s MLCC alternatives to your design.

Additional Resources

There are other resources available like Panasonic’s White Papers on Understanding Polymer and Hybrid Capacitors, Polymer Capacitors - An Optimal Replacement For MLCCs, and a free E-Learning training on MLCC Alternatives.