CTI600 refers to an insulation material grade with a Comparative Tracking Index of 600V, which is currently the highest safety performance level (UL Level 0) in international standards. This indicator is crucial for the long-term reliability of printed circuit boards (PCBs), especially in harsh environments such as high voltage, high humidity, and pollution.

CTI600 is the top benchmark for insulation safety, achieving ultra-high resistance to leakage and tracing through optimized resin substrates, providing core guarantees for high-voltage, high-density, and highly reliable PCB design. In scenarios such as new energy, industrial automation, and explosion-proof equipment, its long-term stability and safety advantages are irreplaceable.

Definition and Level Status of CTI600 PCB

1. Testing Standards

The CTI value is tested according to the International Electrotechnical Commission standard * * IEC-112 * *: 50 drops of 0.1% ammonium chloride electrolyte are added to the surface of the material, and the voltage is gradually increased until a leakage trace is formed. The highest voltage value it can withstand is the CTI value. CTI600 is a material that can withstand a voltage of 600V without leaving any traces of leakage.

2. Security level classification

-UL standard: The highest level (Level 0) is TI ≥ 600V.

-IEC standard: divided into 4 levels, CTI600 belongs to the highest category.

**Common board comparison * *:

|Board type | CTI range (V) | Grade (UL)|

|Ordinary FR-4 (glass fiber base) | 175-225 | Grade 3|

|Composite substrate (CEM series) | 150-175 | Grade 4|

|Paper substrate (FR-1) | ≤ 150 | Grade 5|

|CTI600 board | ≥ 600 | Grade 0 |

Technological advantages and application value of CTI600

1. High density wiring design

CTI600 board allows for smaller line spacing (minimum leakage distance), suitable for high-density interconnect (HDI) PCBs. At the same operating voltage, its safety distance can be reduced by 30% to 50% compared to ordinary FR-4, significantly improving wiring flexibility.

2. Reliability in Extreme Environments

-Anti leakage marking: In high temperature, high humidity, and polluted environments, ordinary boards are prone to short circuit failure due to the formation of conductive pathways caused by surface carbonization; CTI600 can effectively inhibit this process.

-* * Long term stability * *: Suitable for scenarios such as industrial power equipment, petrochemical plants, and rail transit that require a safety life of>10 years.

3. * * Improvement of material properties**

By optimizing the molecular structure of the resin (reducing easily carbonized groups), high CTI can be achieved while also considering:

-Flame retardancy: Meets UL94 V-2 standard.

-* * Environmental adaptability * *: Operating temperature range of * * -50 ℃~100 ℃ * *, humidity tolerance of 80% RH.

Testing methods and key parameters of CTI600

1. * * Testing process**

-Electrolyte: 0.1% ammonium chloride solution (simulated pollutant).

-Judgment criteria: The highest voltage at which there are no conductive traces after 50 drops of solution are dropped.

2. * * Differentiation of related concepts**

- **CTI vs PTI**：

-CTI: The maximum voltage value at which the material can withstand the electrolyte (dynamic testing).

-PTI: * * Passeability test * * of material withstand specified voltage (e.g. 1.5kV/50 drops).

Typical application scenarios of CTI600

1. * * High security electronic devices**

-Explosion proof electrical appliances (such as methane detection equipment, requiring PCB line width ≤ 0.15mm).

-Medical equipment power module, high-voltage control system for new energy vehicles.

2. * * Industrial weather resistant components**

-Case: Weidm ü ller's PCB card slot (AP series) uses PA 66 insulation material with CTI ≥ 600, which is used in mechanical, electrical, chemical and other fields to ensure long-term stability at 80% humidity.

3. * * High power/high voltage PCB**

Such as server power supplies and photovoltaic inverters, it is necessary to avoid the risk of breakdown caused by leakage tracing.

Selection precautions of CTI600

-* * Cost trade-off * *: The cost of TI600 board is significantly higher than that of ordinary FR-4 (about 2-3 times), and a comprehensive safety needs assessment is needed.

-Design Specification: Referring to the IEC-950 standard, calculate the minimum creepage distance based on the operating voltage and CTI value.

-* * Failure Prevention * *: Low CTI boards are prone to delamination and CAF (Conductive Anode Wire) failure in humid environments, and CTI600 can fundamentally reduce such risks.

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