4 ms·
What about for microcontrollers? I've seen some sequences of fairly specific capacitor values for 3.3V power in some microcontroller datasheets, and I always wo
by satiric 2y ago
What about for microcontrollers? I've seen some sequences of fairly specific capacitor values for 3.3V power in some microcontroller datasheets, and I always wondered how much that mattered.
- serviceberry 2y agoIt's hard to generalize. Common microcontroller clock speeds range from 1 to 500 MHz. An 8-bit microcontroller running at 1 MHz will often work fine without any decoupling at all. A 32-bit microcontroller might not even boot without a ceramic capacitor nearby. The basic answer is basically what the original article says. If you don't want the mental burden of figuring it out, the spec gives you safe defaults that should work for almost all uses. But it's almost never the case that you need to do it that way.
- picture 2y agoUsually the value isn't a big deal for "power rails" which expect to have additional capacitors connected elsewhere. However, sometimes microcontrollers expose decoupling pins for use with internal voltage converters and regulators (for example the core voltage on older STM32 parts), and those require very specific values that correspond with the tuning of feedback networks and power converter design within the IC
- satiric 2y agoThanks, that makes sense.