Power net portal is a special schematic object used to define a power or ground net. Power ports allow you to conveniently indicate a power net at any location in the design. Power nets of the same designator automatically connect throughout your design #portal #power
A generic fixed inductor for rapid developing circuit topology. *You can now change the footprint and 3D model at the top level anytime you want. This is the power of #generics
U1 is a WIZnet W5500, which is a hardwired TCP/IP embedded Ethernet controller. This chip provides an easier way to achieve internet connectivity in embedded systems.
Key features and abilities of U1 (W5500) include:
A single-chip solution that embeds TCP/IP stack, 10/100 Ethernet MAC and PHY. This enables users to implement an Ethernet application by adding just the simple socket program.
Capability to support TCP, UDP, IPv4, ICMP, ARP, IGMP, and PPPoE protocols.
Support for high-speed SPI (Serial Peripheral Interface) for easy integration with the external microcontroller.
Internal 32KB memory buffer for processing Ethernet packets.
Capacity to support 8 independent hardware sockets simultaneously.
Provision of Wake on LAN (WOL) and power down mode options which are useful for reducing power consumption.
Built-in PHY embedded for 10BaseT/100BaseTX.
Given its features, the W5500 is suited for a variety of embedded applications like home networking devices, serial-to-Ethernet, parallel-to-Ethernet, USB-to-Ethernet, GPIO-to-Ethernet, security systems, and factory and building automations.
In your project, it serves as the central component handling all the Ethernet and internet connectivity functions.
The W5500 Ethernet chip restarting due to electrostatic discharge (ESD) could indicate that the circuit lacks sufficient protections against ESD. There are several steps you can take to help protect your circuit:
ESD Protection Devices: These can be placed at the Ethernet connector inputs (RJ-45). TVS diodes are often used for this purpose. They are designed to protect the circuit by clamping the voltage when the ESD occurs.
Grounding: In your project, make sure that all the ground points (identified as Exclude from BOM: true) are properly connected with minimal impedance, especially the AGND pins on IC (like U1:(AGND)). Capacitors on power supply pins (U1:(AVDD) and U1:(VDD)) should be placed as close as possible to the IC pins, with the ground side going directly to a large ground plane.
Decoupling Capacitors: Use decoupling capacitors close to the power supply pins of the W5500. Already in your project, capacitors like C19, C22, C14 etc. are connected across power supply lines for this purpose.
Appropriate Layout: Always try to keep all Ethernet-related traces as short as possible to limit antenna-effect picking up environment ESD. Also, ensure that the PCB traces have the proper impedance matching.
Isolated Power Supply: Use of isolated DC-DC converter for providing power to the Ethernet PHYs could be beneficial in keeping noise due to ESD out of your system power rails.
Isolate IC from Human Interactions: Try to isolate the W5500 IC from interfaces accessible to humans, like Buttons, LEDs etc. These are common points where ESD could get in.
Please verify these strategies are in place in your design. The problem could also just be a bad unit or a marginal power supply. But power looks good in your design based on U2:(VIN) coming from a 12V source +12V:(P1) and properly decoupled using capacitors C19 and C21.
Remember that ESD protection is a holistic process and requires considerations at the system level, PCB level, and component level.
The W5500 chip by WIZnet can indeed be susceptible to Electrostatic Discharge (ESD) damage, like many other semiconductor devices. ESD can cause permanent damage to the chip, which might be why your W5500 has stopped working.
If an ESD event has damaged the W5500 in your PoE project, the best solution would be to replace the component. However, there are steps you can take to prevent ESD damage in the future:
ESD Protection Devices: Consider using external ESD protection devices such as TVS diodes. They can shunt the high voltage transients produced by an ESD event away from sensitive circuit elements. Connect them as close as possible to the connector leading to sensitive devices like Ethernet chips.
Grounding: Ensure a clear and efficient grounding system. A well-designed system provides a path for the ESD dissipation.
Correct Handling Procedures: Always handle components with care at all stages to avoid any unnecessary ESD. Operators should be grounded using ESD wrist straps when handling these devices.
ESD Safe Workspace: Work in an ESD-protected area and use ESD-safe storage for sensitive components.
PCB Layout: In the PCB Layout, it can be helpful to have some ESD protection too. This could include things like ground guard rings and placement of components and traces in the layout to minimize exposure to potential ESD sources.
Restarting because of Electrostatic Discharge (ESD) is a common problem in many devices, and the W5500 isn't an exception. When ESD occurs, it can cause the device to reset or reboot due to the brief unexpected change in power.
Here are some suggestions to mitigate ESD issues that cause your circuit to restart:
ESD protection components: Use Electrostatic Discharge (ESD) protection components such as ESD suppression diodes or Transient Voltage Suppression (TVS) diodes. They can be placed close to the input/output lines that are exposed to ESD strikes.
Use of Filters: You can use Ferrite Beads or EMI filters on power supply lines to suppress unwanted interference, which might be causing a reboot.
Power Supply Decoupling: Ensure good Power Supply decoupling near the chip. Consider having 100nF capacitors (like C14, C15, C16) placed as closely as possible to the power pins of the W5500 (U1) to filter out high-frequency noise on the power supply line. For larger transients, use bulk capacitors like C21, which has a value of 100uF.
Optimizing PCB Layout: Keep the trace lengths of I/O lines and power lines as short as possible, and use proper grounding. Try to route sensitive signals and power traces away from potentially noisy ones.
Handling and Environment: Be sure to follow ESD-safe handling procedures when working with the assembly. Use of ESD-protective work surface or mat, ESD-safe tools, protective packaging, and grounding are all essential when working with sensitive electronic components.
Remember to debug your board carefully to confirm that the ESD is indeed the cause of the problem, other reasons could include software bugs, power supply instability, or other issues.
Finally, the use of ESD protection and precautions could shift the issue from the chip level to a system level, where the entire system can handle ESD strikes without system resets or other malfunctions.
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why are the RSVD Pins connected trough a 10k resistor to ground and not direcly,...
Connecting reserved (RSVD) pins directly to ground, as typically recommended in datasheets, ensures the pins are held at a stable potential with minimal voltage drop, avoiding potential floating issues. However, using a resistor like 10kΩ adds flexibility, allowing for potential reconfiguration or debugging options, as it enables the possibility to slightly lift the pin potential if necessary without completely isolating it.
Here are some reasons for using a resistor instead of a direct connection:
Debugging/Testing: The resistor allows measuring the current or voltage across the pins without altering the circuit significantly.
Reconfigurability: If future design changes require connecting the RSVD pin to a different voltage level, the resistor allows for easier adjustments.
Safety Margin: The resistor offers protection against accidental short circuits or current surges, which might affect the pin or the rest of the circuit.
Nevertheless, it's crucial to consult the chipset's specific datasheet and reference designs to ensure that using resistors on RSVD pins doesn't conflict with the intended operation, as manufacturers usually have reserved pins configured for stability and predictability. Would you like assistance on any particular design aspect of the W5500 PoE project?
The W5500 PoE Project is an electronics design for a 10/100 Base-T/TX PHY Ethernet controller that supports Power-over-Ethernet (PoE) using the W5500 chip with an SPI interface. It is intended for use as a PoE injector.
Would you like more details about its functionality, key components, or design considerations?
pjbutcher
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