Timeline for MLCC - Can I use high voltage rated caps for very low voltage scenarios?
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Aug 5, 2018 at 20:28 | comment | added | Spehro Pefhany | The limit on operating voltage for low voltage MLCC caps is actually from capacitance decrease, not breakdown voltage. Analogous to saturation current being limiting for inductor peak operating current. As Photon says, 6.3 and even lower are common. | |
| Aug 5, 2018 at 17:50 | comment | added | The Photon | RE "Typical SMD ceramic capacitors are rated at like 50 V". Not if you move to smaller sizes (0402 and lower) and values above 1 nF. Right now I'm doing part selection and working hard to find 10 V ratings rather than 6.3 or even 4.something volts. | |
| Aug 5, 2018 at 16:29 | comment | added | Tom Carpenter | Just as an example, TDK give lots of data on their caps. This one is a bog standard 10uF, 10V, X7R cap. At 10V DC bias it is down to 4uF, at 5V it is 7.5uF. That's why you typically want the rated voltage to be over 2x the required DC voltage. | |
| Aug 5, 2018 at 16:25 | comment | added | Tom Carpenter | "but it won't reach the specified capacitance above the rated voltage" - Most MLCCs don't get anywhere near their rated capacitance at their rated voltage under DC bias. Typically by the time you get to half the rated voltage, for an X5R, the capacitance has already dropped below half the rated value. For X7R, you might get 70% rated capacitance by the time you reach half the rated voltage. | |
| Aug 5, 2018 at 15:31 | history | answered | JRE | CC BY-SA 4.0 |