Shengyi S1600 is an FR-4.0 laminate developed for PCB designs that need strong resistance to surface electrical tracking. Its defining specification is CTI PLC 0, corresponding to at least 600V under IEC 60112. Shengyi lists power-supply boards, displays, televisions, refrigerators and washing machines among the intended applications.
S1600 should not be selected as a high-Tg or low-loss upgrade. The official datasheet gives a DSC Tg of 135°C, Td of 310°C and Dk/Df of 4.5/0.017 at 1GHz. The engineering case for this material is high CTI, supported by the correct creepage layout, contamination controls and finished-product safety evaluation.
What Is Shengyi S1600?
S1600 is a glass-reinforced epoxy laminate and prepreg family classified by Shengyi as UL ANSI FR-4.0. The official features are high CTI, UV blocking and good mechanical processability. Shengyi also warns that solder-mask rework is not recommended and that applications with CAF requirements need systematic reliability assessment.
This positioning separates three different decisions. CTI concerns tracking resistance on an insulating surface. Tg and Td describe resin thermal behavior under specified tests. CAF resistance concerns conductive filament growth within the laminate structure. A strong result in one category does not prove strength in the others.
Official S1600 Datasheet Properties
The following values come from Shengyi document CN-TDS-2101-04-S1600. The sheet states that typical values are based on a 1.6mm, 8 × 7628 specimen and are reference values rather than finished-board guarantees.
| Property | Typical value | Condition | Test method / note |
|---|---|---|---|
| CTI | PLC 0 (≥600V) | Condition A | IEC 60112 |
| Tg | 135°C | DSC | IPC-TM-650 2.4.25D |
| Td | 310°C | TGA, 5% weight loss | IPC-TM-650 2.4.24.6 |
| T260 / T288 | 15 / 2 min | TMA | IPC-TM-650 2.4.24.1 |
| Thermal stress | >100s | 288°C solder dip | IPC-TM-650 2.4.13.1; no delamination |
| Z-axis CTE | 55 / 308 ppm/°C; 4.5% | Before / after Tg; 50–260°C total | IPC-TM-650 2.4.24 |
| Dk / Df | 4.5 / 0.017 | 1GHz, C-24/23/50 | IPC-TM-650 2.5.5.9 |
| Peel strength, 1oz | 1.8 N/mm (10.28 lb/in) | 288°C / 10s | IPC-TM-650 2.4.8 |
| Flexural strength | 550 / 450 MPa | LW / CW, condition A | IPC-TM-650 2.4.4 |
| Water absorption | 0.10% | D-24/23 | IPC-TM-650 2.6.2.1 |
| Flammability | V-0 | C-48/23/50 | UL 94; confirm recognized construction |
What Does CTI ≥600V Mean for PCB Design?
CTI measures the voltage at which conductive tracking develops across an insulating surface under a standardized contamination test. S1600’s PLC 0 classification places it in the highest CTI material group used for creepage-distance calculations under standards that reference material groups.
That result does not authorize a universal spacing reduction. Required creepage also depends on working voltage, pollution degree, overvoltage category, insulation type, altitude and the applicable product-safety standard. Clearance through air is a separate calculation. Your compliance engineer must approve the final distances.
Where Does S1600 Add the Most Value?
S1600 is relevant when conductive contamination, condensation or long-term surface leakage is a design concern. Power-supply boards, appliance controls and display power sections may combine mains voltage, dust, humidity and narrow mechanical envelopes. A high-CTI substrate provides a stronger material basis, while layout and protective measures manage the complete risk.
For refrigerators and washing machines, review condensation paths, detergent or dust exposure, connector placement and coating coverage. For power boards, separate primary and secondary circuits, slots and barriers must be evaluated together. QFPCB manufactures to the released fabrication data; safety certification remains a finished-product responsibility.
Why S1600 Is Not a High-Tg Upgrade
The official Tg is 135°C by DSC and T288 is 2 minutes. Those numbers are materially different from high-Tg FR-4 families intended for repeated severe lead-free assembly or thick high-layer-count structures. Choose S1600 because CTI is the controlling requirement, not because “special material” implies better performance everywhere.
If thermal cycling, multiple reflows or plated-hole reliability dominate, compare a qualified high-Tg PCB material with an appropriate CTI rating. A material substitution should preserve every required property, certification and construction—not only Tg or CTI.
CAF, Tracking and Moisture Are Different Risks
Surface tracking develops along an insulating surface. CAF develops internally along glass-resin interfaces under electrical bias and moisture. Water absorption is another material test and does not by itself prove either finished-board tracking or CAF performance.
Shengyi explicitly advises systematic reliability assessment when S1600 is considered for applications with CAF requirements. QFPCB therefore needs voltage bias, conductor spacing, humidity profile, test duration and acceptance criteria before reviewing a CAF-sensitive design. We do not convert the high CTI label into an unsupported anti-CAF claim.
S1600 Stackup, Impedance and HDI Review
S1600 may be used in multilayer designs when its thermal window and available constructions match the project. Its published 1GHz Dk/Df values are reference measurements, not a universal design Dk for every prepreg resin content. Pressed thickness, glass style, copper thickness and routing geometry must be modeled together.
QFPCB provides impedance simulation and technical support for multilayer PCB, hybrid PCB and HDI projects, including Any-Layer HDI when the structure passes engineering review. PCB engineer Alan has more than 10 years of PCB CAM engineering experience. Technical email: [email protected]. We confirm the proposed S1600 construction before committing to impedance geometry or sequential lamination.
Manufacturing and Solder-Mask Controls
Shengyi describes S1600 as mechanically processable, but its datasheet specifically says solder-mask rework is not recommended. Rework can change surface cleanliness, mask coverage and insulation geometry in precisely the region where tracking resistance matters. The production plan should prevent mask defects rather than assume repeated stripping and recoating is harmless.
During DFM, QFPCB checks mask dams, exposed conductor edges, slots, creepage paths, high-voltage nets and contamination-sensitive areas. Ionic cleanliness, coating and assembly-process requirements must be stated separately because laminate CTI does not control residues introduced later.
Available Laminate Thickness and Copper
The official purchasing table lists laminate thicknesses from 0.8mm to 3.2mm and copper foil from 12µm to 70µm. Standard sheet sizes are 1020 × 1220mm, 915 × 1220mm and 1070 × 1220mm, with other options subject to manufacturer confirmation.
These ranges describe Shengyi supply formats, not QFPCB real-time stock. Send the finished thickness, layer copper, required S1600 callout and permitted alternatives. We will confirm current core/prepreg combinations and whether the proposed stackup can meet resin fill, thickness and electrical requirements.
How Should Purchasing Specify S1600?
The purchase drawing should name Shengyi S1600 rather than only stating “FR-4” or “CTI 600.” It should also identify the applicable IPC-4101 slash sheet, UL evidence, laminate thickness, copper foil, finished-board thickness and any customer-approved alternatives. If equivalence is permitted, define the properties and certifications that an alternative must preserve.
Do not approve a substitute from CTI alone. Compare Tg, Td, T260/T288, Z-axis expansion, flammability, Dk/Df, moisture behavior and the exact recognized construction. Availability can vary by thickness, copper and prepreg style, so QFPCB checks the released stackup against current supply before quotation. For regulated equipment, purchasing documentation should also define certificates, lot traceability and change-notification expectations.
Files Needed for an S1600 PCB Quote
- Gerber, ODB++ or IPC-2581 fabrication data and NC drill files
- Layer order, finished thickness and copper weight by layer
- Exact S1600 material and IPC-4101/21 or customer specification callout
- Working voltage, insulation class, creepage and clearance requirements
- CTI, UL, CAF, coating and cleanliness requirements
- Impedance table and reference layers when controlled impedance is required
- Surface finish, solder mask, assembly profile and quantities
Providing these inputs allows QFPCB to distinguish a material requirement from a complete high-voltage safety requirement. If the drawing only says “high CTI,” purchasing and engineering should agree on the exact grade and evidence needed before production.
Frequently Asked Questions
What is the CTI of Shengyi S1600?
The official S1600 datasheet reports CTI PLC 0, corresponding to at least 600V under IEC 60112. This supports high-CTI material selection, but it does not independently define PCB creepage distance. Working voltage, pollution degree, insulation category, altitude and the relevant product standard still control the released layout.
What is the Tg of S1600?
Shengyi reports a typical DSC Tg of 135°C using IPC-TM-650 2.4.25D. S1600 is therefore not positioned as a high-Tg laminate. Select it primarily for tracking resistance, and separately verify whether its Tg, T260, T288 and assembly window suit the board thickness and thermal history.
Is S1600 suitable for power-supply PCBs?
Yes, Shengyi lists power-supply boards as an application. S1600 can be useful where surface tracking resistance is important, but the complete design must still address creepage, clearance, slots, barriers, pollution, coating, thermal rise and applicable safety standards. A CTI value is one input, not finished-product certification.
Can S1600 be used in refrigerators or washing machines?
Yes. Shengyi lists refrigerators and washing machines among its applications. In these products, evaluate condensation, contaminants, connector locations, mains separation and coating coverage. Confirm that the finished PCB and assembly meet the appliance standard and environmental qualification rather than relying only on the laminate designation.
Is S1600 an anti-CAF material?
No such conclusion should be made from the official sheet. Shengyi states that applications with CAF requirements need systematic reliability assessment. CAF is an internal electrochemical failure mechanism, while CTI addresses surface tracking. Provide the humidity-bias test requirement and conductor geometry for engineering review.
Is S1600 a low-loss material?
No. The official sheet reports Dk 4.5 and Df 0.017 at 1GHz under C-24/23/50 conditioning. Those values can support early impedance work, but they do not position S1600 as a low-loss high-speed or RF laminate. Choose it when CTI is the dominant requirement.
Can S1600 support multilayer or HDI PCB construction?
It can be evaluated for multilayer and HDI designs, subject to available prepreg, resin fill, dielectric thickness and sequential-lamination review. The material’s 135°C Tg and short published T288 require attention in thermally demanding builds. QFPCB confirms the actual construction before approving an HDI stackup.
Why does Shengyi discourage solder-mask rework?
The official S1600 datasheet explicitly says solder-mask rework is not recommended. Because mask stripping and recoating can affect surface condition, coverage and insulation geometry, the safest approach is to prevent defects through artwork review and controlled processing. Any deviation should receive project-specific engineering approval.
Request an S1600 PCB Review
Send QFPCB your fabrication files, S1600 requirement, voltage map, creepage and clearance rules, stackup and environmental conditions. We will review material availability, manufacturability, impedance needs and the high-voltage layout inputs before quotation.
Official sources: Shengyi S1600 product page and official S1600 TDS.
