TPS543X

Part: TPS5430, TPS5431 from Texas Instruments

Type: Synchronous Buck Converter

Description: The TPS543x is a 3-A, wide input range, step-down converter with an integrated 110 mΩ MOSFET, offering up to 95% efficiency, a fixed 500 kHz switching frequency, and an adjustable output voltage down to 1.22 V with 1.5% initial accuracy.

Operating Conditions:

• Supply voltage: TPS5430: 5.5–36 V; TPS5431: 5.5–23 V
• Operating temperature: -40 to 125 °C
• Switching frequency: 500 kHz (fixed)
• Output voltage range: Adjustable down to 1.22 V

Absolute Maximum Ratings:

• Max supply voltage: TPS5430: 40 V; TPS5431: 25 V
• Max junction temperature: 125 °C

Key Specs:

• Input Voltage Range (TPS5430): 5.5 V to 36 V
• Input Voltage Range (TPS5431): 5.5 V to 23 V
• Continuous Output Current: Up to 3 A
• Peak Efficiency: Up to 95%
• Output Voltage Accuracy: 1.5% initial accuracy (adjustable down to 1.22 V)
• Switching Frequency: 500 kHz (fixed)
• Shutdown Quiescent Current: 18 µA (typ)
• UVLO Start Threshold Voltage: 5.3 V (typ)

Features:

• Wide Input Voltage Range
• Up to 3-A Continuous (4-A Peak) Output Current
• High Efficiency up to 95% Enabled by 110 mΩ Integrated MOSFET Switch
• Wide Output Voltage Range: Adjustable Down to 1.22 V with 1.5% Initial Accuracy
• Internal Compensation Minimizes External Parts Count
• Fixed 500 kHz Switching Frequency for Small Filter Size
• Improved Line Regulation and Transient Response by Input Voltage Feed Forward
• System Protected by Overcurrent Limiting, Overvoltage Protection and Thermal Shutdown
• -40°C to 125°C Operating Junction Temperature

Applications:

• Consumer: Set-top Box, DVD, LCD Displays
• Industrial and Car Audio Power Supplies
• Battery Chargers, High Power LED Supply
• 12-V/24-V Distributed Power Systems

Package:

• Thermally Enhanced 8-Pin SO PowerPAD™ Package
• HSOP (8)

• Wide Input Voltage Range:
  • TPS5430: 5.5 V to 36 V
  • TPS5431: 5.5 V to 23 V
• Up to 3-A Continuous (4-A Peak) Output Current
• High Efficiency up to 95% Enabled by 110 m Ω Integrated MOSFET Switch
• Wide Output Voltage Range: Adjustable Down to 1.22 V with 1.5% Initial Accuracy
• Internal Compensation Minimizes External Parts Count
• Fixed 500 kHz Switching Frequency for Small Filter Size
• Improved Line Regulation and Transient Response by Input Voltage Feed Forward
• System Protected by Overcurrent Limiting, Overvoltage Protection and Thermal Shutdown
• -40°C to 125°C Operating Junction Temperature
• Available in Small Thermally Enhanced 8-Pin SO PowerPAD™ Package

• Consumer: Set-top Box, DVD, LCD Displays
• Industrial and Car Audio Power Supplies
• Battery Chargers, High Power LED Supply
• 12-V/24-V Distributed Power Systems

T₁ = -40 °C to 125°C, VIN = 12 V (unless otherwise noted)

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Copyright © 2006–2014, Texas Instruments Incorporated

over operating free-air temperature range (unless otherwise noted) ⁽¹⁾⁽²⁾

⁽¹⁾ Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

⁽²⁾ All voltage values are with respect to network ground terminal.

⁽³⁾ Approaching the absolute maximum rating for the VIN pin may cause the voltage on the PH pin to exceed the absolute maximum rating.

⁽²⁾ JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

The TPS543x is a 3-A, step down regulator with an integrated high side MOSFET. This device is typically used to convert a higher DC voltage to a lower DC voltage with a maximum available output current of 3 A. Example applications are: High Density Point-of-Load Regulators for Set-top Box, DVD, LCD and Plasma Displays, High Power LED Supply, Car Audio, Battery Chargers, and other 12-V and 24-V Distributed Power Systems. Use the following design procedure to select component values for the TPS543x. This procedure illustrates the design of a high frequency switching regulator. Alternatively, use the WEBENCH software to generate a complete design. The WEBENCH software uses an iterative design procedure and accesses a comprehensive database of components when generating a design.

To begin the design process a few parameters must be decided upon. The designer needs to know the following:

• Input voltage range
• Output voltage
• Input ripple voltage
• Output ripple voltage
• Output current rating
• Operating frequency

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8.2 Typical Applications

8.2.1 12-V Input to 5.0-V Output

Figure 9 shows the schematic for a typical TPS5430 application. The TPS5430 can provide up to 3 A output current at a nominal output voltage of 5 V. For proper thermal performance, the exposed PowerPAD^{\text{TM}}underneath the device must be soldered down to the printed-circuit board.

Figure 9. Application Circuit, 12 V Input to 5.0 V Output

8.2.1.1 Design Requirements

For this design example, use the following as the input parameters:

(1) As an additional constraint, the design is set up to be small size and low component height.

Copyright © 2006–2014, Texas Instruments Incorporated