| Architecture | Pros | Cons |
| A: Buck Converter + LDO | - Noise reduction at select, typically lower, frequencies (high speed peripherals OFF)
- Cascaded LDOs with single switching converter give similar ripple rejection
| - Low light and full load efficiency
- Limited ripple rejection across a higher frequency bandwidth, requiring a larger output capacitor
- Thermal performance
|
| B: FPWM Buck Converter | - Fixed output ripple voltage across load variations
- Better transient response for large load changes
- High full load efficiency
- Simple solution
| - Extremely low light load efficiency
- IQ (FPWM devices typically in mA range of IQ)
|
| C: Buck Converter + PI Filter | - Very high light & full load efficiency
- Strong noise attenuation at higher switching frequencies (high speed peripherals ON)
| - Dependency of PI filter on load conditions/range
- Limited low frequency rejection for PFM voltage ripple
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