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I'm building a small board that uses the MMA8453Q Freescale Accelerometer.

The datasheet requires a 4.7μF decouple capacitor on the \$V_{dd}\$ pin. I only have 3.3μF or 6.8μF capacitors on hand. Could I use them instead? What's the risk of using a different value decoupling capacitor?

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  • \$\begingroup\$ Probably either will be perfectly OK but go for the 6.8uF. \$\endgroup\$ – Andy aka Oct 8 '13 at 7:22
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Large decoupling capacitors such as those are meant to compensate for larger sags in the supply of the chip. Using a larger value will not hurt.

Don't skimp out on the smaller value decoupling capacitor though, since it's used to filter high-frequency noise from/on the supply; use as close to the prescribed value as possible, otherwise use a 100nF.

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  • \$\begingroup\$ There can be issues with too-large decoupling caps causing power supply sagging if they're connected/disconnected, but they're not common. \$\endgroup\$ – Connor Wolf Oct 8 '13 at 8:27

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