How it works
An MLCC stacks ceramic layers between alternating metal electrodes. Every active layer adds capacitance in parallel. C0G uses a comparatively stable dielectric, so its capacitance changes little with temperature and does not show the pronounced DC-bias loss associated with high-permittivity Class II ceramics. That stability is valuable when the capacitor defines a filter corner, resonant frequency or timing interval. The trade-off is capacitance density: achieving a large value may need more space or may be unavailable. Package inductance and electrode resistance still matter at high frequency; a stable dielectric does not make the complete component an ideal capacitor.
The ceramic separates adjacent electrodes and determines temperature behaviour, bias dependence and losses.
Parameters that matter
- Capacitance and tolerance
- The nominal value and allowed initial deviation under the specified measurement conditions. (pF, nF; %, or pF for small values)
- Temperature coefficient
- C0G is nominally 0 ±30 ppm/°C; 30 ppm equals 0.003% per °C. Confirm the part's operating range. (ppm/°C)
- Rated voltage
- Maximum allowed voltage under the manufacturer's conditions; do not treat DC and AC ratings as interchangeable. (Vdc or Vac)
- Q, ESR and impedance
- Loss and impedance at the actual operating frequency, not only at the capacitance test frequency. (dimensionless; Ω; frequency in Hz)
- Size and height
- The body and pad geometry; RF behaviour and assembly compatibility depend on more than capacitance. (mm plus inch/metric code)
A worked selection example
Illustrative calculation · not a product guarantee
A small timing capacitor
Illustrative design: 1.00 nF, ±1% initial tolerance, 25°C reference, operation at 75°C; use the 30 ppm/°C coefficient bound. Ignore other drift terms only for this short example.
- Temperature change = 75 − 25 = 50°C.
- Temperature contribution ≤ 30 × 50 = 1500 ppm = 0.15%, or 1.5 pF.
- Initial tolerance contributes 10 pF. A simple first-order worst-case budget is about ±11.5 pF (±1.15%).
- Add the timing resistor, IC threshold and parasitic capacitance to the real timing error budget; they can dominate this result.
A tight printed tolerance is useful only when the whole circuit's error budget is checked.
Where it fits
Suitable starting points
- RC timing and stable analog filters
- RF matching or resonant circuits after checking Q and self-resonance
- Small signal paths where voltage-dependent capacitance is undesirable
Where to take extra care
- Large bulk capacitance where size dominates
- A generic replacement for a safety capacitor
- RF or power resonance selected solely from C0G marking
Series directions to investigate
Start with standard 0402/0603/0805 inch packages if the layout permits; for RF, compare actual high-Q series models. Fenghua's general C0G and HQ/CQ catalogue families are listed in its public catalogue, not a promise that every value and voltage exists.
What Chinese suppliers can offer
Where the opportunity lies
Fenghua publishes general C0G and dedicated HQ/CQ MLCC families. A mainland candidate can be evaluated on the same stable-capacitance, assembly and RF requirements as the incumbent.
What still needs evidence
Do not assume a catalogue C0G has the same RF loss, self-resonance or lot history as an established high-Q part. Availability and manufacturing-site evidence require an exact MPN inquiry.
Questions for the supplier
- 01
What exact MPN, tolerance and reference measurement conditions apply?
- 02
Can you supply Q/ESR or S-parameter data across our frequency range?
- 03
What are the temperature coefficient, voltage rating and component height for this exact value?
- 04
Which manufacturing lot, factory and traceability documents will accompany the samples?
Technical references
These references support the principles and catalogue directions discussed here. Public documentation is a different evidence level from a supplier reply, a lot document or an independent test. This guide does not claim those later stages have been completed.
Reading the source trail
The Murata product page is a concrete C0G specification reference, not a proposed substitute. Its FAQ supports the DC-bias discussion. Fenghua’s documents support catalogue directions only. A test report must still match the candidate’s construction, stress conditions and sample lot before it can support your purchasing decision.
See a document-coverage issue log- 1. C0G product characteristics
- 2. DC bias and capacitance FAQ
- 3. General Series Multi-layer Ceramic Capacitors A0006
- 4. MLCC product catalogue
These guides explain selection principles. Final decisions require the current datasheet for the exact ordering code, operating conditions and appropriate application testing.