Circuit Design Principles for Minimizing ESD Failures
Avoid connecting the pins of ESD-sensitive devices, such as CMOS devices, directly to connector pins. Use protection devices between the device and the connector pins.
When designing logic circuits, avoid using edge-triggered devices. If an ESD transient pulse enters the circuit, such inputs are likely to cause system malfunction. It is best to use level-detection logic with a validation strobe signal to improve the circuit's ESD resistance.
Select components with the required ESD resistance to implement the required function. For example, ESD is a common cause of device failure in RS-232 applications. Devices with built-in ESD protection networks and transient suppressors are more resistant to ESD. Ensure that the device meets the ESD standards of the relevant application system.
If a sensitive device in the circuit does not have built-in ESD protection circuitry, provide external protection circuitry. You can generally connect TVS diodes to ground at critical inputs and outputs, use series resistors on inputs to limit inrush current, and connect decoupling capacitors to power supply pins.
If your design uses shielded cable, ensure 360° contact between the cable and the shield to avoid antenna effects (radiated fields). Follow EMI mitigation precautions to reduce the impact of external electromagnetic fields and prevent harmful emissions that could affect nearby equipment.
You can largely control ESD by using appropriate materials to encapsulate ESD-sensitive electronic components. Manufacturers typically use antistatic tubes, boxes, bags, and similar materials to store components and circuit boards.