SBOA583 December   2023 OPA205 , OPA206 , OPA210 , OPA2206 , OPA2210 , OPA2392 , OPA2828 , OPA320 , OPA328 , OPA365 , OPA392 , OPA397 , OPA828

 

  1.   1
  2.   Abstract
  3. 1 Introduction
  4. 2 Circuit Configuration Impact on Common-Mode Range
  5. 3 Practical Input Limitations
  6. 4 Input Phase Reversal (Inversion)
  7. 5 Common-Mode Limitations Inside Bipolar Amplifiers
  8. 6 Common-Mode Limitations Inside CMOS Amplifiers
  9. 7 Rail-to-Rail CMOS Amplifiers
  10. 8 Output Swing Limitations Inside a Bipolar Op Amp
  11. 9 Linearity of Output Swing Specifications
  12. 10Output Voltage Swing vs Output Current
  13. 11Classic Bipolar vs Rail-to-Rail Output Stage for CMOS and Bipolar
  14. 12Rail-to-Rail Output and Open-Loop Gain Dependence
  15. 13Output Short-Circuit Protection
  16. 14Overload Recovery
  17. 15Supply Current During Input and Output Swing Limitations
  18. 16Summary
  19. 17References

4 Input Phase Reversal (Inversion)

Normally when an op-amp input is driven beyond the common-mode range, the output becomes distorted or clipped. During the early years of op-amp semiconductor development some amplifiers exhibited a different phenomenon when the common-mode range was exceeded, called phase reversal. When the common-mode range is exceeded for a device with phase reversal, the output actually moves in the opposite of the expected direction. Figure 4-1 illustrates this issue on a buffer amplifier. Notice that when the input moves positively beyond the common-mode range the output actually moves negatively. This problem is related to a design oversight, and all modern amplifiers are designed and tested so that this issue is no longer a problem. Even legacy devices that once had phase reversal, have generally been revised to correct this issue. This section is included in the document to alleviate concerns related to legacy literature. Most modern data sheets include a line item indicating no phase reversal.

GUID-20231006-SS0I-G9TK-FQXQ-DC9RFNJDJPFR-low.svg Figure 4-1 Phase Inversion (Reversal)