PCB Board Classification
Posted:10:40 AM August 26, 2021
PCB Board performance introduction and selection
We can classify the PCB by resin type of sheet and TG of the sheet.
1. Classification of resin type of sheet
- 1. Phenolic resin (Phenolic), FR2, low-grade board, generally single-sided, used for ordinary consumer electronic products.
- 2. Epoxy, such as FR4 series S1141, IT180A, is used for general consumer electronics, products, and industrial control electronics
- 3. Polyimide resin (Polyimide, PI), such as 85N, is used in electronic products with better heat resistance.
- 4. Polytetrafluorethylene (Polytetrafluorethylene, referred to as PTFE or called
- TEFLON), such as RT5880.
- 5. Bismaleamide triazine resin (abbreviated as BT)
- Such as Mitsubishi CCL-HL832HS
- 6. Cyanide Ester (abbreviated as CE)
2. Classified according to the Tg of the sheet
- 1. Ordinary Tg sheet: 130 ～ 140℃
- 2. Medium Tg sheet: 150～160℃
- 3. High Tg sheet: ≥170℃
- 4. Ultra-high Tg sheet: 250-260℃
- a. Polyimide resin materials are mainly used in aerospace, oil drilling, military industry and other fields that require very high reliability;
- b. Arlon 85N 33N
- c. VT-901
- d. The price of Tenghui board is relatively cheaper than Arlon.
3. Main considerations for material selection
- 1. The availability of materials in a timely manner; such as the procurement cycle and the time when the product is put into use.
- 2. PCB manufacturability; whether the required board is suitable for the existing craftsmanship.
- 3. Reliability of resistance to lead-free soldering;
- 4. Cost factors; customer R&D expenditure and cost control.
- 5. Applicability of laws and regulations, etc.; whether it conforms to RoHS, UL, etc. Considering the above factors specifically involves the following aspects:
- a. Heat resistance of Tg, Td, and small pitch;
- b. Dk and Df (dielectric constant and dielectric loss)
- c. Halogen content (whether it is a halogen-free material)
- d. Other considerations: CAF resistance, CTI value, CTE, water absorption, etc.
4. The rules of conventional sheet selection
- 1. Td requirement≥340℃: IT180A, TU-768
- 2. Dk≤3.5, Df≤0.01: select high-performance FR-4, PTFE, non-PTFE, BT
- 3. Halogen-free materials: medium Tg S1150G, IT-158; high Tg: S1165, IT-170GRA
- 4. Plates with CTI requirements
- 5. High-speed material classification