SPVA018 August   2025 LM2904B

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2ESD Overview
    1. 2.1 What is Electrostatic Discharge?
      1. 2.1.1 ESD Cell Robustness in Semiconductors
  6. 3Types of ESD Cells
    1. 3.1 Dual Diode Configuration
      1. 3.1.1 Why Not Always Use Dual Diode Configuration?
    2. 3.2 Bootstrapped Diodes
    3. 3.3 Absorption Devices
      1. 3.3.1 Active Clamps
      2. 3.3.2 GCNMOS Clamps
    4. 3.4 Silicon Controlled Rectifiers
    5. 3.5 CER and ECR NPN Diodes
      1. 3.5.1 Measuring the Response of an ECR and CER ESD Cell
    6. 3.6 Comparison of ESD Cells
  7. 4How to Determine the ESD Structure of the Device from the Data Sheet
  8. 5How to Protect The System from In Circuit ESD/EOS Events
    1. 5.1 Using TVS Diodes and Series Resistance for Circuit Protection
    2. 5.2 Using Schottky Diodes for Circuit Protection
  9. 6How to Test an Op Amp in a System Level Circuit
    1. 6.1 ESD Protection Cell Advancements Over the Years
  10. 7Summary
  11. 8References

3 Types of ESD Cells

So, how do we protect against ESD? There must be protection against thousands of volts that can discharge within nanoseconds. The answer is simple: use a diode. At the core, all ESD cells are variations of a diode. A diode, which is essentially a PN junction, clamps high voltages when the diode enters a forward biased state. However, in its reversed bias state, it acts as a high impedance and allows for normal operation. This makes it an excellent method to protect against ESD cells without compromising the normal operation of the IC.

There are many different types of ESD cells. However, there are advantages and disadvantages to each ESD cell. In this section, the most common forms of ESD cells is discussed, and how IC designers select the right cell type for the device.