What is the normal leakage current range for surface mount capacitors?

The normal leakage current range of surface mount capacitors depends on the capacitor type, material, rated voltage, and working environment. The leakage current of capacitors with different media and structures varies significantly. The following are classification explanations and key data, combined with industry standards and actual measurement specifications:
1、 Definition and influencing factors of leakage current
Leakage current refers to the small current leakage caused by incomplete dielectric insulation of a capacitor at rated voltage. Mainly influenced by three factors:
Material characteristics: Electrolytic capacitors (containing aluminum/tantalum) have much higher leakage current than ceramic capacitors due to the presence of liquid/solid electrolytes.
Voltage and Capacity: Leakage current is positively correlated with operating voltage (V) and nominal capacity (C), and the industry standard formula is I ≤ K × C × V (K is the material coefficient).
Temperature: For every 10 ℃ increase in temperature, the leakage current of the electrolytic capacitor may double.
2、 Normal range of leakage current for various types of surface mount capacitors
1. Ceramic capacitors (MLCC)
Typical value: 0.01 μ A~1 μ A (low voltage small capacity models can be as low as pA level).
characteristic:
NPO (COG) material has the lowest leakage current (close to ideal insulation), followed by X7R/Y5V;
Almost unaffected by voltage, but high-capacity models (>10 μ F) experience capacity decay under DC bias, while leakage current remains at an extremely low level.
2. Aluminum electrolytic capacitors
Calculation formula: I ≤ 0.01 × C (μ F) × V (V) or 3 μ A, take the larger value (test conditions: 20 ℃, 2 minutes).  
Example: 100 μ F/25V capacitor, calculated value=0.01 × 100 × 25=25 μ A, actual requirement ≤ 25 μ A.
High temperature tolerance: In an environment of 105 ℃, the leakage current is allowed to be ≤ 2 times the initial value (after durability testing).
3. Tantalum capacitors and hybrid types
Solid state polymer tantalum capacitor: The leakage current is about 0.1CV~0.5CV (unit: μ A), which is better than aluminum electrolysis.
Hybrid capacitors (such as RVE series): The leakage current is between aluminum electrolysis and solid tantalum, with a typical value of 5 μ A~50 μ A.
3、 Leakage current testing standards and conditions
Testing method:
Apply rated voltage for 60-90 seconds and read with a leakage current tester;
Industrial inspection often uses DC withstand voltage testing (such as 1.05 times the rated voltage).
Judgment criteria:
Consumer electronics: Refer to IEC 60384-14 and JIS C 5101-4 standards;
Automotive/military grade: Must meet AEC-Q200 or MIL-PRF-49470, with stricter leakage current requirements (such as ≤ 1.5 times the calculated value at high temperatures).
4、 Risk and Control of Abnormal Leakage Current
Risk:
Excessive leakage current → circuit power consumption increases, signal distortion (such as sensor drift);
The leakage current of electrolytic capacitors may cause overheating and explosion (requiring the cooperation of overvoltage protection circuit).
Control measures:
The incoming inspection shall be carried out according to formula I ≤ 0.03CV+20 μ A (enterprise standard, stricter than the general formula);
After high-temperature aging test (105 ℃/1000 hours), the leakage current should not double.
5、 Selection suggestions and typical application references
Capacitor type, leakage current range, applicable scenarios, testing voltage conditions
MLCC (NPO)<0.1 μ A high-frequency circuit, RF module rated voltage DC
MLCC (X7R) 0.1 μ A~1 μ A power decoupling, motherboard filtering rated voltage DC
Aluminum electrolytic capacitor 3 μ A~100 μ A power input filter, adapter 1.05 times rated voltage
Solid state tantalum capacitor 1 μ A~50 μ A, portable device CPU power supply rated voltage DC
Note: In actual design, a margin needs to be reserved. For high temperature scenarios (>85 ℃), it is recommended to select leakage current at 50% of the standard value.
summarize
Ceramic capacitors have extremely low leakage current (below μ A level), suitable for high-precision circuits;
Electrolytic capacitors need to be strictly verified according to the formula of I ≤ 0.01CV, and the rating needs to be reduced for high-temperature applications;
Fields with high reliability requirements (automotive/medical) should choose automotive grade or low K value materials (such as solid polymers).
During testing, it is necessary to control the ambient temperature and humidity (standard conditions: 20 ± 5 ℃, 65% RH) to avoid misjudgment.