SLVSGP3A May   2023  – February 2024 TPS54KB20

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Internal VCC LDO and Using External Bias On the VCC Pin
      2. 6.3.2  Enable
      3. 6.3.3  Adjustable Soft Start
      4. 6.3.4  Power Good
      5. 6.3.5  Output Voltage Setting
      6. 6.3.6  Remote Sense
      7. 6.3.7  D-CAP4 Control
      8. 6.3.8  Multifunction Select (MSEL) Pin
      9. 6.3.9  Low-side MOSFET Zero-Crossing
      10. 6.3.10 Current Sense and Positive Overcurrent Protection
      11. 6.3.11 Low-side MOSFET Negative Current Limit
      12. 6.3.12 Overvoltage and Undervoltage Protection
      13. 6.3.13 Output Voltage Discharge
      14. 6.3.14 UVLO Protection
      15. 6.3.15 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Auto-Skip Eco-mode Light Load Operation
      2. 6.4.2 Forced Continuous-Conduction Mode
      3. 6.4.3 Powering the Device From a Single Bus
      4. 6.4.4 Powering the Device From a Split-rail Configuration
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1  Output Voltage Setting Point
        2. 7.2.2.2  Choose the Switching Frequency and the Operation Mode
        3. 7.2.2.3  Choose the Inductor
        4. 7.2.2.4  Set the Current Limit (ILIM)
        5. 7.2.2.5  Choose the Output Capacitor
        6. 7.2.2.6  RAMP Selection
        7. 7.2.2.7  Choose the Input Capacitors (CIN)
        8. 7.2.2.8  Soft-Start Capacitor (SS Pin)
        9. 7.2.2.9  EN Pin Resistor Divider
        10. 7.2.2.10 VCC Bypass Capacitor
        11. 7.2.2.11 BOOT Capacitor
        12. 7.2.2.12 RC Snubber
        13. 7.2.2.13 PG Pullup Resistor
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

6.3.8 Multifunction Select (MSEL) Pin

The device provides Forced Continuous-Conduction Mode (FCCM) operation for tight output ripple applications and auto-skip Eco-mode for high light-load efficiency. The device allows users to select the switching frequency and operation mode by connecting a resistor from the MSEL pin to AGND pin. Additionally, the user can use the MSEL pin to select the internal ramp amplitude and ramp zero to optimize the control loop for fastest transient response. More details on the different ramp settings are given in Section 6.3.7. Table 6-4 lists the resistor values for the switching frequency, operation mode, and ramp selection. A ±1% tolerance resistor with a typical temperature coefficient of ±100ppm/°C is required for accurate detection across the device operating range.

The MSEL state is set and latched during the internal power-on delay period. Changing the MSEL pin resistance after the power-on delay does not change the status of the device.

To make sure the internal circuit detects the resistor value correctly, do not place any capacitor on the MSEL pin.

Table 6-4 MSEL Pin Selection
MSEL PIN RESISTANCE TO AGND (kΩ) OPERATION MODE UNDER LIGHT LOAD SWITCHING FREQUENCY
(fSW) (kHz)(1)		 RAMP
0 (SHORT) FCCM 800 RAMP4
4.99 FCCM 800 RAMP3
7.50 FCCM 800 RAMP2
10.5 FCCM 800 RAMP1
13.3 FCCM 1100 RAMP4
16.9 FCCM 1100 RAMP3
21.0 FCCM 1100 RAMP2
24.9 FCCM 1100 RAMP1
30.1 FCCM 1400 RAMP4
35.7 FCCM 1400 RAMP3
42.2 FCCM 1400 RAMP2
48.7 FCCM 1400 RAMP1
56.2 Skip-mode 800 RAMP4
64.9 Skip-mode 800 RAMP3
75.0 Skip-mode 800 RAMP2
86.6 Skip-mode 800 RAMP1
102 Skip-mode 1100 RAMP4
118 Skip-mode 1100 RAMP3
137 Skip-mode 1100 RAMP2
158 Skip-mode 1100 RAMP1
182 Skip-mode 1400 RAMP4
210 Skip-mode 1400 RAMP3
243 Skip-mode 1400 RAMP2
≥280 (FLOAT) Skip-mode 1400 RAMP1
(1) Switching frequency varies across input voltage, output voltage, and load. See Figure 5-12 through Figure 5-19.