Anti-static measures for production plant equipment should generally be based on electronic components with electrostatic discharge (ESD) sensitivity not less than 2 levels. If components with electrostatic discharge (ESD) sensitivity of Class 1 must be used, the protection circuit should be placed at the lowest level of the instrument or equipment, and the electrostatic discharge (ESD) voltage should be no less than Class 2.
Anti-static usually takes the following measures:
1. All the different input leads of the MOS device should not be left floating. It should be connected to the power ground, power (source) Vss or power (drain) VDD depending on the circuit.
2. Connect resistors in series with each input of the MOS device.
3. The output of the CMOS device (except the analog switch) can be used to separate each output from the cable line with a resistor and clamp the circuit to Vss or VDD with two high speed switching diodes.
4. When using long input cables, a filter network should be used.
5. At the input of an electrostatic discharge (ESD) sensitive bipolar component, an external RC network consisting of a resistor with a large resistance value and a capacitor with a capacity of not less than 100 pF is externally connected to reduce the effects of electrostatic discharge (ESD). When the circuit characteristics are specified, two parallel diodes can also be used to clamp the 0.5V voltage across each polarity to shunt the input to ground.
6. Do not connect the leads of electrostatic discharge (ESD) sensitive components mounted on the printed circuit board directly to the electrical connector terminals without any protective circuit.