SLVAFX0 October   2024 TLV702 , TLV703 , TLV755P , TPS74401 , TPS7A13 , TPS7A14 , TPS7A20 , TPS7A21 , TPS7A49 , TPS7A52 , TPS7A53 , TPS7A53B , TPS7A54 , TPS7A57 , TPS7A74 , TPS7A83A , TPS7A84A , TPS7A85A , TPS7A91 , TPS7A92 , TPS7A94 , TPS7A96 , TPS7H1111-SP

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction to linear regulator turn-on time
  5. 2What impacts the LDO rise time?
    1. 2.1 Simple Use Cases
      1. 2.1.1 Case 1: LDO with an NR filter but without CFF capacitance
      2. 2.1.2 Case 2: NR filter with a CFF capacitance
      3. 2.1.3 Fast-charge circuitry
      4. 2.1.4 Non-ideal LDO behavior
        1. 2.1.4.1 Applied voltage bias
        2. 2.1.4.2 Fast charge current tolerance
        3. 2.1.4.3 Internal error amplifier offset voltage
        4. 2.1.4.4 Temperature impacts the fast-charge current source
        5. 2.1.4.5 Error amplifier common mode voltage
        6. 2.1.4.6 Reference voltage (VREF) ramp time dominates the turn-on time
        7. 2.1.4.7 Start-up during dropout mode
        8. 2.1.4.8 Large values of COUT induce internal current limit
        9. 2.1.4.9 Limitations of large-signal LDO bandwidth
    2. 2.2 Specific Use Cases and Examples
      1. 2.2.1 Case 3: Precision voltage reference with RNR/SS and parallel IFC fast charge
      2. 2.2.2 Case 4: Precision voltage reference with IFC fast charge and no RNR/SS
      3. 2.2.3 Case 5: Precision current reference
      4. 2.2.4 Case 6: Soft-start timing
  6. 3System Considerations
    1. 3.1 Inrush current calculation
    2. 3.2 Inrush current analysis
    3. 3.3 Maximum slew rate
  7. 4LDO regulators referenced in this paper
  8. 5Conclusion
  9. 6References

6 References

  1. Thomas, Roland E., Rosa, Albert J. The analysis and design of linear systems, 4th ed. ISBN 978-1118065587
  2. Lathi, B.P. Signal Processing & Linear Systems ISBN 978-0195219173
  3. Texas Instruments, data sheet: TPS7A20 300-mA, Ultra-Low-Noise, Low-IQ, High PSRR LDO
  4. Texas Instruments, data sheet: TPS7A49 36-V, 150-mA, Ultralow-Noise, Positive Linear Regulator
  5. Texas Instruments, data sheet: TPS7A91 1-A, High-Accuracy, Low-Noise LDO Voltage Regulator
  6. Texas Instruments, data sheet: TPS7A74 1.5-A, Low-Dropout Linear Regulator With Programmable Soft-Start
  7. Texas Instruments, data sheet: TPS7B4250-Q1 50-mA 40-V Voltage-Tracking LDO With 5-mV Tracking Tolerance
  8. Liu, Jason. “Various Applications for Voltage-Tracking LDO.” Texas Instruments application report, literature No. SLVA789, 2016
  9. Texas Instruments, application report: Zhang, Penn, and Jason Song. Avoid Start-Up Overshoot of LDO.
  10. Texas Instruments, data sheet: TPS7A84A 3-A, High-Accuracy (0.75%), Low-Noise (4.4-µVRMS) LDO Regulator
  11. Texas Instruments, data sheet: TPS7A96 2-A, Ultra-Low Noise, Ultra-High PSRR, RF Voltage Regulator
  12. Texas Instruments, data sheet: TPS7H1111-SP and TPS7H1111-SEP 1.5-A, Ultra-Low Noise, High PSRR Radiation Hardened Low Dropout (LDO) Linear Regulator
  13. Texas Instruments, data sheet: TPS7A57 5-A, Low-VIN (0.7 V), Low-Noise (2.1 µVRMS), High-Accuracy (1%), Ultra-Low Dropout (LDO) Voltage Regulator
  14. Texas Instruments, data sheet: TPS74401 3.0-A, Ultra-LDO with Programmable Soft-Start
  15. Texas Instruments, data sheet: TPS748A 1.5-A, Low-Dropout Linear Regulator With Programmable Soft-Start
  16. G. T. Nobauer and H. Moser, Analytical approach to temperature evaluation in bonding wires and calculation of allowable current, in IEEE Transactions on Advanced Packaging, vol. 23, no. 3, pp. 426-435, Aug. 2000
  17. Renesas, application note: Overcoming Minimum Vdd Ramp Rate Limitation
  18. TI E2E Forum
  19. Texas Instruments, data sheet: AM64x SitaraTM Processors, Section 6.10.2.1
  20. DC and AC Bias Dependence of Capacitors Including Temperature Dependence, DesignCon East 2011
  21. Stephen Ziel, Tips, tricks and advanced applications of linear regulators, Texas Instruments Power Supply Design Seminar SEM2600, 2024