Electrostatic Discharge Information

Static-Safe Workstation

Electrostatic discharge (ESD) can damage or destroy electronic components. All work on instruments and electronic components should be performed at a static-safe workstation as shown in the following figure . The static-safe workstation uses two types of ESD protection:

  • Conductive table-mat and wrist-strap combination.
  • Conductive floor-mat and heel-strap combination.
Example of Static-Safe Workstation

The following suggestions may reduce ESD damage that occurs during testing and servicing operations.

  • Personnel should be grounded with a resistor-isolated wrist strap.
  • Be sure all instruments are properly earth-grounded to prevent a buildup of static charge.

These techniques for a static-safe workstation should not be used when working on circuitry with a voltage potential greater than 30V rms, 42.4V peak, or 60V DC volts.

Only the table-mat and wrist-strap combination provides adequate ESD protection when used alone. To ensure your safety, the static-safe accessories must provide at least 1 MΩ of isolation from ground. Purchase acceptable ESD accessories from your local supplier.

Electrical channel input circuits and the trigger input circuit can be damaged by electrostatic discharge (ESD). Therefore, avoid applying static discharges to the front-panel input connectors. Prior to connecting any coaxial cable to the connectors, momentarily short the center and outer conductors of the cable together. Avoid touching the front-panel input connectors without first touching the frame of the instrument. Be sure that the instrument is properly earth-grounded to prevent buildup of static charge. Wear a wrist-strap or heel-strap.

Grounding Receptacle

If the instrument has a grounding receptacle, you can plug the wrist strap into the grounding receptacle. For example, the DCA-X mainframe has a front-panel grounding receptacle that is shown in the following picture.

Daily ESD Self Check

  1. Visually check your work area to see that there are no static-generating materials, insulating work surfaces, or static-generating tools.
  2. Clear your work area of static charge generators for a distance of at least 1 meter from ESD sensitive items.
  3. Visually check that the ground wiring to the workstation has not been disconnected or damaged.
  4. If applicable, make certain that your work station air ionizer is activated and correctly positioned.
  5. Make sure that there are no static generators inside conductive containers with ESD sensitive items.
  6. Visually check that all ESD sensitive parts, assemblies, or products are completely inside closed conductive containers.
  7. Make sure that all shielding containers have an approved static attention label on the outside.
  8. Make sure that all cleaners, solvents, coatings, and sprays used at your workstation are types approved by your ESD Coordinator.
  9. Put on wrist strap and conductive footwear, and any special garments which are required in your job.
  10. Don’t allow anyone who is not grounded closer than 1 meter to your static safe area.

Protecting TDR/TDT Modules that have 3.5 mm Input Connectors

The Keysight N9355CK01 is a DC coupled limiter (DC to 26.5 GHz) that is used to protect sensitive oscilloscope channels from damage due to electric overload stress (EOS) and electrostatic discharge (ESD). For example, voltages in excess of ±2V can damage high-performance samplers used in oscilloscopes. The limiter dramatically reduces the likelihood that such voltages will reach the sensitive part of the instrument, ensuring that the oscilloscope will perform reliably. Instruments with dual electrical channels, such as the 54754A, will require two N9355CK01 limiters. Step generators within the TDR modules use ≤0.2V, which is less than the diode threshold of the N9355CK01 limiter. The N9355CK01 can also be used to protect the electrical channel of the 86105x and similar modules, as long as the signal does not exceed –0.5V to +0.5V. The N9355CK01's voltage drop is ±0.6V to 0.7V at ±10 mADC.

The N9355CK01 will protect instruments from occasional and short voltage spikes. A major power source, such as a high voltage and current supply can still cause severe damage to the limiter itself, or the instruments. Operators should continue using industry standard EOS and ESD practices to minimize this risk.

Figure. Two N9355CK01s Inserted into Signal Paths