SBVS291C April   2017  – December 2020 TPS7A84A

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics: General
    6. 6.6 Electrical Characteristics: TPS7A8400A
    7. 6.7 Electrical Characteristics: TPS7A8401A
    8. 6.8 Typical Characteristics: TPS7A8400A
    9. 6.9 Typical Characteristics: TPS7A8401A
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Voltage Regulation Features
        1. 7.3.1.1 DC Regulation
        2. 7.3.1.2 AC and Transient Response
      2. 7.3.2 System Start-Up Features
        1. 7.3.2.1 Programmable Soft Start (NR/SS)
        2. 7.3.2.2 Internal Sequencing
          1. 7.3.2.2.1 Enable (EN)
          2. 7.3.2.2.2 Undervoltage Lockout (UVLO) Control
          3. 7.3.2.2.3 Active Discharge
        3. 7.3.2.3 Power-Good Output (PG)
      3. 7.3.3 Internal Protection Features
        1. 7.3.3.1 Foldback Current Limit (ICL)
        2. 7.3.3.2 Thermal Protection (Tsd)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Regulation
      2. 7.4.2 Disabled
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 External Component Selection
        1. 8.1.1.1 Adjustable Operation
        2. 8.1.1.2 ANY-OUT Programmable Output Voltage
        3. 8.1.1.3 ANY-OUT Operation
        4. 8.1.1.4 Increasing ANY-OUT Resolution for LILO Conditions
        5. 8.1.1.5 Current Sharing
        6. 8.1.1.6 Recommended Capacitor Types
        7. 8.1.1.7 Input and Output Capacitor Requirements (CIN and COUT)
        8. 8.1.1.8 Feed-Forward Capacitor (CFF)
        9. 8.1.1.9 Noise-Reduction and Soft-Start Capacitor (CNR/SS)
      2. 8.1.2 Start-Up
        1. 8.1.2.1 Circuit Soft-Start Control (NR/SS)
          1. 8.1.2.1.1 Inrush Current
        2. 8.1.2.2 Undervoltage Lockout (UVLO)
        3. 8.1.2.3 Power-Good (PG) Function
      3. 8.1.3 AC and Transient Performance
        1. 8.1.3.1 Power-Supply Rejection Ratio (PSRR)
        2. 8.1.3.2 Output Voltage Noise
        3. 8.1.3.3 Optimizing Noise and PSRR
          1. 8.1.3.3.1 Charge Pump Noise
        4. 8.1.3.4 Load Transient Response
      4. 8.1.4 DC Performance
        1. 8.1.4.1 Output Voltage Accuracy (VOUT)
        2. 8.1.4.2 Dropout Voltage (VDO)
          1. 8.1.4.2.1 Behavior When Transitioning From Dropout Into Regulation
      5. 8.1.5 Sequencing Requirements
      6. 8.1.6 Negatively Biased Output
      7. 8.1.7 Reverse Current Protection
      8. 8.1.8 Power Dissipation (PD)
        1. 8.1.8.1 Estimating Junction Temperature
        2. 8.1.8.2 Recommended Area for Continuous Operation (RACO)
    2. 8.2 Typical Applications
      1. 8.2.1 Low-Input, Low-Output (LILO) Voltage Conditions
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Evaluation Models
        2. 11.1.1.2 Spice Models
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary

8.1.1.1 Adjustable Operation

The TPS7A84A can be used either with the internal ANY-OUT network or by using external resistors. Using the ANY-OUT network allows the TPS7A8400A to be programmed from 0.8 V to 3.95 V and from 0.5 V to 2.075 V for the TPS7A8401A. For an output voltage range greater than 2.075 V for the TPS7A8401A and 3.95 V for the TPS7A8400A and up to 5.15 V, external resistors must be used. This configuration is referred to as the adjustable configuration of the TPS7A84A throughout this document. The output voltage is set by two resistors, as shown in Figure 8-1. 0.75% accuracy can be achieved with an external BIAS for VIN lower than 2.2 V.

GUID-8D7AF3AF-C552-42A9-9149-6B948CB04E00-low.gifFigure 8-1 Adjustable Operation

R1 and R2 can be calculated for any output voltage range using Equation 1. This resistive network must provide a current equal to or greater than 5 μA for dc accuracy. TI recommends using an R1 approximately 12 kΩ to optimize the noise and PSRR.

Equation 1. VOUT = VNR/SS × (1 + R1 / R2)

Table 8-1 shows the resistor combinations required to achieve several common rails using standard 1%-tolerance resistors.

Table 8-1 Recommended Feedback-Resistor Values (TPS7A8400A)(1)
TARGETED OUTPUT VOLTAGE
(V)		FEEDBACK RESISTOR VALUESCALCULATED OUTPUT VOLTAGE
(V)
R1 (kΩ)R2 (kΩ)
0.912.41000.899
0.9512.466.50.949
1.0012.449.90.999
1.1012.433.21.099
1.2012.424.91.198
1.5012.414.31.494
1.8012.4101.798
1.9012.18.871.89
2.5012.45.92.48
2.8512.14.752.838
3.0012.14.422.990
3.3011.83.743.324
3.6012.13.483.582
4.511.82.554.502
5.0012.42.374.985
(1) R1 is connected from OUT to FB; R2 is connected from FB to GND.
Table 8-2 Recommended Feedback-Resistor Values (TPS7A8401A)(1)
TARGETED OUTPUT VOLTAGE
(V)		FEEDBACK RESISTOR VALUESCALCULATED OUTPUT VOLTAGE
(V)
R1 (kΩ)R2 (kΩ)
0.61154.90.600
0.710.225.50.700
0.7510200.750
0.810.717.80.800
0.91113.70.901
1.09.099.091.000
1.0511101.050
1.110.78.871.103
1.29.316.651.200
1.5115.491.502
1.810.23.921.801
3.3010.71.913.301
5.0010.21.135.013