Bailibo Testing Multilayer Ceramic Capacitor Electrical Performance Testing Project Analysis

MLCCMultilayer ceramic capacitors are one of the most common passive components in electronic equipment. The evaluation of its electrical performance involves a number of parameters. Bailibo Testing's analysis of the electrical performance testing items of multilayer ceramic capacitors

1. Capacitance value and loss

Capacitance value is the basic parameter of the capacitor, reflecting the ability to store charge. During actual measurement, the capacitance value will change with the test frequency, temperature and bias voltage.

The loss factor (or loss tangent) represents the proportion of energy loss inside the capacitor. Low loss is particularly important for high-frequency circuits and high-current applications. Excessive loss will cause the device to heat up.

The equivalent series resistance is the resistance component introduced by the internal electrodes, dielectric, etc. of the capacitor. It is associated with the loss factor, which directly affects the efficiency and heat generation of the capacitor.

2. Insulation and voltage resistance

Leakage current reflects the insulation performance of the capacitor dielectric material under DC voltage. Excessive leakage current means reduced insulation performance, which may lead to increased power consumption or early failure.

Withstand voltage testing is used to verify the capacitor's ability to withstand a set voltage. During the test, apply a voltage higher than the rated value to check whether breakdown occurs or the leakage current exceeds the standard. This is a basic means of assessing safety margins.

3. Frequency and temperature characteristics

The frequency characteristic curve shows the relationship between capacitance value, loss factor and other parameters as the frequency changes. The capacitance of MLCC remains stable below the self-resonant frequency, and becomes inductive after exceeding it. There are significant differences in the frequency response of materials with different dielectric constants.

The temperature characteristic curve describes the change of capacitance value with ambient temperature. MLCCs with different temperature levels such as X7R, X5R, and C0G have large differences in capacitance temperature drift ranges. For equipment operating in a wide temperature range, this curve is an important reference for selection.

4. DC bias characteristics

This is a phenomenon unique to high dielectric constant MLCC. When a DC voltage is applied, its capacitance will drop significantly, possibly by dozens of percentage points near the rated voltage. When the AC signal is superimposed on the DC bias, the actual effective capacitance needs to be derated based on this curve.

5. Nyquist curve

The Nyquist curve is used to describe the complex impedance characteristics of capacitors at different frequencies in impedance spectrum analysis. The horizontal axis is the real part (resistance), and the vertical axis is the imaginary part (reactance). Parameters such as equivalent series resistance, equivalent series inductance and insulation resistance can be analyzed through the curve, which is helpful for diagnosing internal states such as dielectric loss and electrode contact.

6. Thermal Excitation Current

Thermal excitation current is used to analyze trap energy levels, charge storage and release behaviors. The capacitor is polarized by applying a voltage at low temperature, then cooled by a short circuit, and then heated at a linear heating rate while recording the released current. This test can reveal the internal defects and ion migration characteristics of the dielectric material, which is of reference significance for evaluating long-term reliability.

Bailibo Testing The above testing items cover the main evaluation dimensions of MLCC in terms of electrical performance. In different application scenarios, the focus of attention is different: power filtering focuses on capacitance, DC bias characteristics and equivalent series resistance; high-frequency circuits focus on frequency characteristics and losses; occasions with high reliability requirements need to pay attention to parameters such as leakage current and thermal excitation current. Understanding the meaning of each test will help in correct selection and use.