STDA017 November   2025 TPS7A33 , TPS7A4501-SP , TPS7A47 , TPS7A47-Q1 , TPS7A4701-EP , TPS7A52 , TPS7A52-Q1 , TPS7A53 , TPS7A53-Q1 , TPS7A53A-Q1 , TPS7A53B , TPS7A54 , TPS7A54-Q1 , TPS7A57 , TPS7A8300 , TPS7A83A , TPS7A84 , TPS7A84A , TPS7A85A , TPS7A90 , TPS7A91 , TPS7A92 , TPS7A94 , TPS7A96 , TPS7B7702-Q1 , TPS7H1111-SEP , TPS7H1111-SP

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction to Parallel LDOs Using Ballast Resistors
  5. 2Noise Analysis of Parallel LDOs Using Ballast Resistors
  6. 3LDO Output Impedance
  7. 4Strategies on Reducing the Noise of the Parallel LDO System
  8. 5Noise of Parallel LDOs Using Ballast Resistors
    1. 5.1 TPS7A57
    2. 5.2 TPS7A94
  9. 6Noise Measurements of Alternative Parallel LDO Architectures
    1. 6.1 TPS7B7702-Q1
  10. 7Conclusion
  11. 8References

5.2 TPS7A94

The TPS7A94 LDO [5] currently provides an industry leading noise spectral density at just 0.46µVRMS (10Hz–100kHz). While the TPS7A94 is rated for a 1A load current, the TPS7A96 is rated for a 2A load current [6]. Both of these LDOs are designed to be paralleled using ballast resistors. Paralleling these LDOs provide the lowest noise possible in linear regulator designs. Up to ten TPS7A94 LDOs are being paralleled in the industry to achieve ultra-low noise power rails. Noise analysis of parallel TPS7A94 LDOs (the conditions described in Section 2) is showcased in Figure 5-2.

TPS7A94 TPS7A96 TPS7A57 TPS7B7702-Q1 Parallel TPS7A94 Noise Performance Figure 5-2 Parallel TPS7A94 Noise Performance