SLVAEX7A December   2020  – January 2023 OPA2310 , OPA310 , OPA348 , OPA4310 , TLV341 , TLV341A , TLV342 , TLV342A

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2Standard Op Amp ESD Protection
    1. 2.1 Standard Op Amp ESD Protection: Structure
    2. 2.2 Standard Op Amp ESD Protection: Considerations
  5. 3Op Amp ESD Protection Without Input Diodes to V+
    1. 3.1 Op Amp ESD Protection Without Input Diodes to V+: Structure
    2. 3.2 Op Amp ESD Protection Without Input Diodes to V+: Considerations
  6. 4How to Measure the ESD Structure Current of an Op Amp
  7. 5Summary
  8. 6References
  9. 7Revision History
  10.   A Measured Data for Op Amps With Alternate ESD Protection

1 Introduction

To help deal with short-term, high-voltage events, amplifiers have electrostatic discharge (ESD) protection structures. These structures typically feature diodes that protect amplifier inputs and outputs from unintended damage by clamping these pins to the supply rails under ESD conditions.

However, these diodes are not designed to be relied upon for electrical overstress (EOS) events where the input voltage significantly exceeds the supply rail for a longer period of time. Under such a scenario, current can flow from the inputs to the supply rails. This can have undesirable effects including, but not limited to, back-powering the amplifier, device damage, and complete device failure. Understanding these scenarios and what can be done to avoid them is important in op amp circuit design.

This application note considers the standard amplifier ESD protection structure as well as an alternative structure that does not have diodes from the inputs to the V+ supply rail. Then, some Texas Instruments devices are highlighted with this alternative input protection structure and how the behavior of the protection structure of an op amp can be measured for certain scenarios.