SBVS267A January   2016  – February 2016 TPS7A85

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configurations 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
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Low-Noise, High-PSRR Output
      2. 7.3.2  Integrated Resistance Network (ANY-OUT)
      3. 7.3.3  Bias Rail
      4. 7.3.4  Power-Good (PG) Function
      5. 7.3.5  Programmable Soft-Start
      6. 7.3.6  Internal Current Limit (ILIM)
      7. 7.3.7  Enable
      8. 7.3.8  Active Discharge Circuit
      9. 7.3.9  Undervoltage Lockout (UVLO)
      10. 7.3.10 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation with 1.1 V ≤ VIN < 1.4 V
      2. 7.4.2 Operation with 1.4 V ≤ VIN ≤ 6.5 V
      3. 7.4.3 Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Recommended Capacitor Types
      2. 8.1.2  Input and Output Capacitor Requirements (CIN and COUT)
      3. 8.1.3  Noise-Reduction and Soft-Start Capacitor (CNR/SS)
      4. 8.1.4  Feed-Forward Capacitor (CFF)
      5. 8.1.5  Soft-Start and In-Rush Current
      6. 8.1.6  Optimizing Noise and PSRR
        1. 8.1.6.1 Charge Pump Noise
      7. 8.1.7  ANY-OUT Programmable Output Voltage
      8. 8.1.8  ANY-OUT Operation
      9. 8.1.9  Increasing ANY-OUT Resolution for LILO Conditions
      10. 8.1.10 Current Sharing
      11. 8.1.11 Adjustable Operation
      12. 8.1.12 Sequencing Requirements
        1. 8.1.12.1 Sequencing with a Power-Good DC-DC Converter Pin
        2. 8.1.12.2 Sequencing with a Microcontroller (MCU)
      13. 8.1.13 Power-Good (PG) Operation
      14. 8.1.14 Undervoltage Lockout (UVLO) Operation
      15. 8.1.15 Dropout Voltage (VDO)
      16. 8.1.16 Behavior when Transitioning from Dropout into Regulation
      17. 8.1.17 Load Transient Response
      18. 8.1.18 Negatively-Biased Output
      19. 8.1.19 Reverse Current Protection
      20. 8.1.20 Power Dissipation (PD)
        1. 8.1.20.1 Estimating Junction Temperature
        2. 8.1.20.2 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
      2. 8.2.2 Typical Application for a 5.0-V Rail
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  9. 9 Power-Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Board Layout
    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 Modules
        2. 11.1.1.2 Spice Models
      2. 11.1.2 Device Nomenclature
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

1 Features

  • Low Dropout: 150 mV (typ) at 4 A
  • 1% (max) Accuracy Over Line, Load, and Temperature
  • Output Voltage Noise:
    • 4.4 µVRMS at 0.8-V Output
    • 8.4 µVRMS at 5.0-V Output
  • Input Voltage Range:
    • Without BIAS: 1.4 V to 6.5 V
    • With BIAS: 1.1 V to 6.5 V
  • ANY-OUT™ Operation:
    • Output Voltage Range: 0.8 V to 3.95 V
  • Adjustable Operation:
    • Output Voltage Range: 0.8 V to 5.0 V
  • Power-Supply Ripple Rejection:
    • 40 dB at 500 kHz
  • Excellent Load Transient Response
  • Adjustable Soft-Start In-Rush Control
  • Open-Drain Power-Good (PG) Output
  • Stable with a 47-µF or Larger Ceramic Output Capacitor
  • Operating Temperature Range:
    –40ºC to +125°C
  • 3.5-mm × 3.5-mm, 20-Pin VQFN

2 Applications

  • Digital Loads: SerDes, FPGAs, and DSPs
  • Instrumentation, Medical, and Audio
  • High-Speed Analog Circuits:
    • VCO, ADC, DAC, and LVDS
  • Imaging: CMOS Sensors and Video ASICs
  • Test and Measurement

3 Description

The TPS7A85 is a low-noise (4.4 µVRMS), low-dropout linear regulator (LDO) capable of sourcing 4 A with only 240 mV of maximum dropout. The device output voltage is pin-programmable from 0.8 V to 3.95 V and adjustable from 0.8 V to 5.0 V using an external resistor divider.

The combination of low-noise (4.4 µVRMS), high-PSRR, and high output current capability makes the TPS7A85 ideal to power noise-sensitive components such as those found in high-speed communications, video, medical, or test and measurement applications. The high performance of the TPS7A85 limits power-supply-generated phase noise and clock jitter, making this device ideal for powering high-performance serializer and deserializer (SerDes), analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and RF components. Specifically, RF amplifiers benefit from the high-performance and 5.0-V output capability of the device.

For digital loads [such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and digital signal processors (DSPs)] requiring low-input voltage, low-output (LILO) voltage operation, the exceptional accuracy (0.75% over load and temperature), remote sensing, excellent transient performance, and soft-start capabilities of the TPS7A85 ensure optimal system performance.

The versatility of the TPS7A85 makes the device a component of choice for many demanding applications.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (nom)
TPS7A85 VQFN (20) 3.50 mm × 3.50 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

Powering RF Components

TPS7A85 7A85_front_1.gif

Powering Digital Loads

TPS7A85 7A85_front_2.gif