SLVSE63B September   2017  – February 2019 TPS61085A-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Soft Start
      2. 7.3.2 Frequency Select Pin (FREQ)
      3. 7.3.3 Undervoltage Lockout (UVLO)
      4. 7.3.4 Thermal Shutdown
      5. 7.3.5 Overvoltage Prevention
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Inductor Selection
        2. 8.2.2.2 Rectifier Diode Selection
        3. 8.2.2.3 Setting the Output Voltage
        4. 8.2.2.4 Compensation (COMP)
        5. 8.2.2.5 Input Capacitor Selection
        6. 8.2.2.6 Output Capacitor Selection
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
  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 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    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

8.2.2.4 Compensation (COMP)

The regulator loop must be compensated by adjusting the external components connected to the COMP pin. The COMP pin is the output of the internal transconductance error amplifier. Standard values of RCOMP = 13 kΩ and CCOMP = 3.3 nF works for the majority of the applications.

See Table 5 for dedicated compensation networks giving an improved load transient response. Equation 8 can be used to calculate RCOMP and CCOMP:

SPACE

Equation 8. TPS61085A-Q1 q3_1_lvs859.gif

Table 5. Recommended Compensation Network Values at High/Low Frequency

FREQUENCY L VS VIN ±20% RCOMP CCOMP
High (1.2 MHz) 3.3 µH 15 V 5 V 82 kΩ 1.1 nF
3.3 V 75 kΩ 1.6 nF
12 V 5 V 51 kΩ 1.1 nF
3.3 V 47 kΩ 1.6 nF
9 V 5 V 30 kΩ 1.1 nF
3.3 V 27 kΩ 1.6 nF
Low (650 kHz) 6.8 µH 15 V 5 V 43 kΩ 2.2 nF
3.3 V 39 kΩ 3.3 nF
12 V 5 V 27 kΩ 2.2 nF
3.3 V 24 kΩ 3.3 nF
9 V 5 V 15 kΩ 2.2 nF
3.3 V 13 kΩ 3.3 nF

Table 5 gives conservatives RCOMP and CCOMP values for certain inductors, input and output voltages providing a very stable system. For a faster response time, a higher RCOMP value can be used to enlarge the bandwidth, as well as a slightly lower value of CCOMP to keep enough phase margin. These adjustments must be performed in parallel with the load transient response monitoring of TPS61085A-Q1.