SBVS304B June   2017  – October 2021 TPS7A83A

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics: General
    6. 7.6 Electrical Characteristics: TPS7A8300A
    7. 7.7 Electrical Characteristics: TPS7A8301A
    8. 7.8 Typical Characteristics: TPS7A8300A
    9. 7.9 Typical Characteristics: TPS7A8301A
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Voltage Regulation Features
        1. 8.3.1.1 DC Regulation
        2. 8.3.1.2 AC and Transient Response
      2. 8.3.2 System Start-Up Features
        1. 8.3.2.1 Programmable Soft-Start (NR/SS)
        2. 8.3.2.2 Internal Sequencing
          1. 8.3.2.2.1 Enable (EN)
          2. 8.3.2.2.2 Undervoltage Lockout (UVLO) Control
          3. 8.3.2.2.3 Active Discharge
        3. 8.3.2.3 Power-Good Output (PG)
      3. 8.3.3 Internal Protection Features
        1. 8.3.3.1 Foldback Current Limit (ICL)
        2. 8.3.3.2 Thermal Protection (Tsd)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Regulation
      2. 8.4.2 Disabled
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 External Component Selection
        1. 9.1.1.1 Adjustable Operation
        2. 9.1.1.2 ANY-OUT Programmable Output Voltage
        3. 9.1.1.3 ANY-OUT Operation
        4. 9.1.1.4 Increasing ANY-OUT Resolution for LILO Conditions
        5. 9.1.1.5 Recommended Capacitor Types
        6. 9.1.1.6 Input and Output Capacitor Requirements (CIN and COUT)
        7. 9.1.1.7 Feed-Forward Capacitor (CFF)
        8. 9.1.1.8 Noise-Reduction and Soft-Start Capacitor (CNR/SS)
      2. 9.1.2 Start Up
        1. 9.1.2.1 Soft-Start (NR/SS)
          1. 9.1.2.1.1 Inrush Current
        2. 9.1.2.2 Undervoltage Lockout (UVLO)
        3. 9.1.2.3 Power-Good (PG) Function
      3. 9.1.3 AC and Transient Performance
        1. 9.1.3.1 Power-Supply Rejection Ratio (PSRR)
        2. 9.1.3.2 Output Voltage Noise
        3. 9.1.3.3 Optimizing Noise and PSRR
          1. 9.1.3.3.1 Charge Pump Noise
        4. 9.1.3.4 Load Transient Response
      4. 9.1.4 DC Performance
        1. 9.1.4.1 Output Voltage Accuracy (VOUT)
        2. 9.1.4.2 Dropout Voltage (VDO)
          1. 9.1.4.2.1 Behavior When Transitioning From Dropout Into Regulation
      5. 9.1.5 Sequencing Requirements
      6. 9.1.6 Negatively Biased Output
      7. 9.1.7 Reverse Current
      8. 9.1.8 Power Dissipation (PD)
        1. 9.1.8.1 Estimating Junction Temperature
        2. 9.1.8.2 Recommended Area for Continuous Operation (RACO)
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 Evaluation Models
        2. 12.1.1.2 Spice Models
      2. 12.1.2 Device Nomenclature
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

9.1.2.2 Undervoltage Lockout (UVLO)

The UVLO circuits ensure that the device stays disabled before the input or bias supplies reach the minimum operational voltage range, and ensures that the device properly shuts down when either the input or BIAS supply collapses.

Figure 9-4 and Table 9-5 show one of the UVLO circuits being triggered to various input voltage events, assuming VEN ≥ VIH(EN).

GUID-E9A18D5A-32CD-4D4D-8377-ED2C2A294A03-low.gifFigure 9-4 Typical UVLO Operation
Table 9-5 Typical UVLO Operation Description
REGION EVENT VOUT STATUS COMMENT
A Turn on, VIN ≥ VUVLO_1,2(IN), and VBIAS ≥ VUVLO(BIAS) Off Start up
B Regulation On Regulates to target VOUT
C Brownout, VIN ≥ VUVLO_1,2(IN) – VHYS_1,2(IN)
or VBIAS ≥ VUVLO(BIAS) – VHYS(BIAS)		 On The output can fall out of regulation but the device is still enabled
D Regulation On Regulates to target VOUT
E Brownout, VIN < VUVLO_1,2(IN) – VHYS_1,2(IN)
or VBIAS ≥ VUVLO(BIAS) – VHYS(BIAS)		 Off The device is disabled and the output falls because of the load and active discharge circuit. The device is re-enabled when the UVLO fault is removed when either the IN or BIAS UVLO rising threshold is reached by the input or bias voltage and a normal start up then follows.
F Regulation On Regulates to target VOUT
G Turn off, VIN < VUVLO_1,2(IN) – VHYS_1,2(IN)
or VBIAS < VUVLO(BIAS) – VHYS(BIAS)		 Off The output falls because of the load and active discharge circuit

Similar to many other LDOs with this feature, the UVLO circuits take a few microseconds to fully assert. During this time, a downward line transient below approximately 0.8 V causes the UVLO to assert for a short time; however, the UVLO circuits do not have enough stored energy to fully discharge the internal circuits inside the device. When the UVLO circuits are not given enough time to fully discharge the internal nodes, the outputs are not fully disabled.

The effect of the downward line transient can be mitigated by using a larger input capacitor to increase the fall time of the input supply when operating near the minimum VIN.