When an exact capacitor part number is out of stock or you are deciphering a faded 3-digit code on a salvaged PCB, a capacitor equivalent chart is your primary translation tool. This reference maps physical capacitance values (pF, nF, µF) to standard EIA 3-digit codes and dictates which dielectric class (C0G, X7R, X5R) is safe for your specific circuit topology. The direct answer for the most common digital decoupling substitution is a 100nF (104 code) X7R capacitor rated at 50V, but high-frequency, timing, and bulk power circuits require strict adherence to the derating rules below.
The Master Capacitor Equivalent Chart (EIA & IEC Standards)
How to read this table: The Value (pF) column is the base SI unit used in RF and high-speed digital design. The EIA 3-Digit Code is the industry-standard marking printed on SMD and radial components; the first two digits are significant figures, and the third is the multiplier (number of zeros) in picofarads. The Dielectric Class column indicates the most common material used for that value range under the EIA RS-198 standard. Temperature ratings for Class I (C0G) are ±30ppm/°C, while Class II (X7R) allows ±15% capacitance shift from -55°C to +125°C.
| Value (pF) | Value (nF) | Value (µF) | EIA 3-Digit Code | Standard Dielectric Class |
|---|---|---|---|---|
| 10 | 0.01 | 0.00001 | 100 | C0G / NP0 (Class I) |
| 22 | 0.022 | 0.000022 | 220 | C0G / NP0 (Class I) |
| 100 | 0.1 | 0.0001 | 101 | C0G / X7R |
| 1,000 | 1.0 | 0.001 | 102 | X7R (Class II) |
| 10,000 | 10.0 | 0.01 | 103 | X7R / X5R (Class II) |
| 100,000 | 100.0 | 0.1 | 104 | X7R / X5R (Class II) |
| 1,000,000 | 1,000.0 | 1.0 | 105 | X5R / X7R (Class II) |
| 10,000,000 | 10,000.0 | 10.0 | 106 | X5R / Tantalum / Polymer |
| 47,000,000 | 47,000.0 | 47.0 | 476 | X5R / Electrolytic |
Dielectric & Voltage Derating: Which Column Applies to You?
The chart above provides nominal values, but in practice, the effective capacitance of Class II dielectrics (X7R, X5R) drops significantly under applied DC voltage—a phenomenon known as DC bias derating. If you are designing or repairing a circuit, the Voltage Rating column on your BOM (Bill of Materials) must be evaluated against the dielectric type.
- Class I (C0G/NP0): No DC bias derating. A 100pF C0G capacitor remains 100pF whether 0V or 50V is applied. Use this column for RF matching networks, crystal oscillator load capacitors, and precision analog filters.
- Class II (X7R/X5R): Severe DC bias derating. According to Murata's ceramic capacitor design guidelines, a 10µF X5R capacitor rated at 10V may only deliver 4µF to 5µF of actual capacitance when 5V DC is applied. Derating Rule: Always select a voltage rating at least 2x (preferably 3x) the maximum DC bus voltage for Class II parts to maintain the nominal chart value.
Decision Tree: Picking the Exact Replacement Part
Use this decision path to terminate your search and select a concrete, off-the-shelf replacement part based on the circuit's function.
| Circuit Function | If-Then Condition | Concrete Part Pick (SMD 0805 Example) |
|---|---|---|
| High-Frequency / Timing | If signal is >1MHz or part of an RC oscillator timing loop → Must use Class I. | 22pF C0G 50V (e.g., KEMET C0805C220J5GACTU) |
| Digital IC Decoupling | If placed across VCC/GND of a microcontroller (ESP32, STM32) → Must use Class II, low ESL. | 100nF (104) X7R 50V (e.g., Murata GRM21BR71H104KA88L) |
| Bulk Power Filtering | If on the output of a buck converter (12V to 5V) → Must use high volumetric efficiency, accept DC bias loss. | 22µF X5R 10V (e.g., Taiyo Yuden LMK212BJ226MG-T) |
| AC Mains Snubber / EMI | If connected Line-to-Neutral or Line-to-Ground → MUST use Safety Rated, ignore standard EIA codes. | 100nF X2 275VAC / 310VAC (e.g., Vishay B32921C3104M) |
What This Chart Cannot Tell You (And When to Stop Guessing)
A capacitance equivalent chart translates value and dielectric, but it is blind to three critical physical parameters that will cause a substitution to fail if ignored:
- Equivalent Series Resistance (ESR): In switching power supplies (like an LM2596 buck converter), the output capacitor must have a specific ESR to maintain control loop stability. Swapping a low-ESR polymer capacitor for a standard X5R ceramic can cause the regulator to oscillate. Always check the regulator datasheet for ESR requirements.
- Ripple Current Rating: For bulk filtering on motor drivers or audio amplifiers, the capacitor must absorb high AC ripple without overheating. Ceramic charts do not list ripple current; you must refer to the manufacturer's specific datasheet (e.g., Cornell Dubilier or TDK Electronics design support pages).
- Physical Lead Pitch (Spacing): For through-hole radial capacitors, a 100nF capacitor might have a 2.5mm, 5.0mm, or 7.5mm lead spacing. The chart cannot tell you if the replacement will physically fit the drilled holes on your PCB. Always measure the hole pitch with calipers before ordering.
Quick-Jump Bookmark Rows for High-Frequency Substitutions
For bench technicians keeping a stock of the most frequently requested substitutions, these three rows cover the vast majority of daily repair and prototyping needs. Bookmark this section for rapid BOM generation.
- The "104" (100nF / 0.1µF): The universal decoupling capacitor. Stock 50V X7R in 0603 and 0805 SMD, plus 50V Y5V/X7R in 2.5mm radial. Used on almost every VCC pin of every 74-series, 4000-series, and modern MCU.
- The "105" (1µF): The standard bulk local-bypass. Stock 16V X7R in 0805 SMD. Frequently paired in parallel with a 100nF to lower the overall impedance profile across a wider frequency band.
- The "220" (22pF): The crystal oscillator standard. Stock 50V C0G/NP0 in 0603 SMD and 5mm radial. Essential for 8MHz, 16MHz, and 32.768kHz Pierce oscillator circuits found in Arduino, ESP32, and RTC modules.
