Select optimal bypass capacitors for stable power delivery to ICs.
Effective decoupling uses multiple capacitors to cover a wide frequency range:
Digital ICs draw current in sharp pulses during clock transitions. Without proper decoupling, these current spikes cause voltage droops that can corrupt data, cause timing errors, or generate electromagnetic interference (EMI).
Capacitors act as local energy reservoirs, supplying instantaneous current that the power supply cannot deliver fast enough.
Creates a low-impedance path to ground for high-frequency noise, preventing it from coupling into sensitive circuits.
Reduces current loop area and contains high-frequency energy locally, minimizing radiated emissions.
| Type | Range | Frequency | Best For | Notes |
|---|---|---|---|---|
| C0G/NP0 | 1pF - 10nF | >100MHz | RF, high-speed digital | Stable, low loss |
| X7R | 1nF - 10µF | 1-100MHz | General purpose | Good balance |
| X5R | 100nF - 100µF | 100kHz-10MHz | Bulk decoupling | Higher capacitance |
| Tantalum | 1µF - 1000µF | <1MHz | Bulk storage | Watch polarity! |
| Electrolytic | 10µF - 10000µF | <100kHz | Input filtering | High ESR, polarized |