ZHCSCW1G September 2014 – January 2017 ISO7340C , ISO7340FC , ISO7341C , ISO7341FC , ISO7342C , ISO7342FC
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 5 說明 （續）
- 6 Pin Configuration and Functions
-
7 Specifications
- 7.1 Absolute Maximum Ratings
- 7.2 ESD Ratings
- 7.3 Recommended Operating Conditions
- 7.4 Thermal Information
- 7.5 Power Ratings
- 7.6 Insulation Specifications
- 7.7 Safety-Related Certifications
- 7.8 Safety Limiting Values
- 7.9 Electrical Characteristics—5-V Supply
- 7.10 Supply Current Characteristics—5-V Supply
- 7.11 Electrical Characteristics—3.3-V Supply
- 7.12 Supply Current Characteristics—3.3-V Supply
- 7.13 Switching Characteristics—5-V Supply
- 7.14 Switching Characteristics—3.3-V Supply
- 7.15 Insulation Characteristics Curves
- 7.16 Typical Characteristics
- 8 Parameter Measurement Information
- 9 Detailed Description
- 10Application and Implementation
- 11Power Supply Recommendations
- 12Layout
- 13器件和文檔支持
- 14機械、封裝和可訂購信息
12 Layout
12.1 Layout Guidelines
A minimum of four layers is required to accomplish a low EMI PCB design (see Figure 28). Layer stacking should be in the following order (top-to-bottom): high-speed signal layer, ground plane, power plane and low-frequency signal layer.
- Routing the high-speed traces on the top layer avoids the use of vias (and the introduction of their inductances) and allows for clean interconnects between the isolator and the transmitter and receiver circuits of the data link.
- Placing a solid ground plane next to the high-speed signal layer establishes controlled impedance for transmission line interconnects and provides an excellent low-inductance path for the return current flow.
- Placing the power plane next to the ground plane creates additional high-frequency bypass capacitance of approximately 100 pF/in2.
- Routing the slower speed control signals on the bottom layer allows for greater flexibility as these signal links usually have margin to tolerate discontinuities such as vias.
If an additional supply voltage plane or signal layer is needed, add a second power or ground plane system to the stack to keep it symmetrical. This makes the stack mechanically stable and prevents it from warping. Also the power and ground plane of each power system can be placed closer together, thus increasing the high-frequency bypass capacitance significantly.
For detailed layout recommendations, see the Digital Isolator Design Guide.
12.1.1 PCB Material
For digital circuit boards operating at less than 150 Mbps, (or rise and fall times greater than 1 ns), and trace lengths of up to 10 inches, use standard FR-4 UL94V-0 printed circuit board. This PCB is preferred over cheaper alternatives because of lower dielectric losses at high frequencies, less moisture absorption, greater strength and stiffness, and the self-extinguishing flammability-characteristics.
12.2 Layout Example
Figure 28. Recommended Layer Stack