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  • TPS54540 4.5-V to 42-V Input, 5 A, Step Down DC-DC Converter with Eco-mode™

    • SLVSBX7B May   2013  – March 2017 TPS54540

      PRODUCTION DATA.  

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  • TPS54540 4.5-V to 42-V Input, 5 A, Step Down DC-DC Converter with Eco-mode™
  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
    6. 6.6 Timing Requirements
    7. 6.7 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  Fixed Frequency PWM Control
      2. 7.3.2  Slope Compensation Output Current
      3. 7.3.3  Pulse Skip Eco-mode
      4. 7.3.4  Low Dropout Operation and Bootstrap Voltage (BOOT)
      5. 7.3.5  Error Amplifier
      6. 7.3.6  Adjusting the Output Voltage
      7. 7.3.7  Enable and Adjusting Undervoltage Lockout
      8. 7.3.8  Internal Soft-Start
      9. 7.3.9  Constant Switching Frequency and Timing Resistor (RT/CLK) Terminal)
      10. 7.3.10 Accurate Current Limit Operation and Maximum Switching Frequency
      11. 7.3.11 Synchronization to RT/CLK Terminal
      12. 7.3.12 Overvoltage Protection
      13. 7.3.13 Thermal Shutdown
      14. 7.3.14 Small Signal Model for Loop Response
      15. 7.3.15 Simple Small Signal Model for Peak Current Mode Control
      16. 7.3.16 Small Signal Model for Frequency Compensation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation with VIN = < 4.5 V (Minimum VIN)
      2. 7.4.2 Operation with EN Control
      3. 7.4.3 Alternate Power Supply Topologies
        1. 7.4.3.1 Inverting Power
        2. 7.4.3.2 Split Rail Power Supply
  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  Custom Design with WEBENCH® Tools
        2. 8.2.2.2  Selecting the Switching Frequency
        3. 8.2.2.3  Output Inductor Selection (LO)
        4. 8.2.2.4  Output Capacitor
        5. 8.2.2.5  Catch Diode
        6. 8.2.2.6  Input Capacitor
        7. 8.2.2.7  Bootstrap Capacitor Selection
        8. 8.2.2.8  Undervoltage Lockout Set Point
        9. 8.2.2.9  Output Voltage and Feedback Resistors Selection
        10. 8.2.2.10 Minimum VIN
        11. 8.2.2.11 Compensation
        12. 8.2.2.12 Discontinuous Conduction Mode and Eco-mode Boundary
        13. 8.2.2.13 Power Dissipation Estimate
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Safe Operating Area
    2. 10.2 Layout Guidelines
    3. 10.3 Layout Example
      1. 10.3.1 Estimated Circuit Area
  11. 11Device and Documentation Support
    1. 11.1 Custom Design with WEBENCH® Tools
    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
  13. IMPORTANT NOTICE

Package Options

Mechanical Data (Package|Pins)
  • DDA|8
    • MPDS092F
Thermal pad, mechanical data (Package|Pins)
  • DDA|8
    • PPTD058I
Orderable Information
  • slvsbx7b_oa
  • slvsbx7b_pm
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DATA SHEET

TPS54540 4.5-V to 42-V Input, 5 A, Step Down DC-DC Converter with Eco-mode™

1 Features

  • High Efficiency at Light Loads with Pulse Skipping Eco-mode™
  • 92-mΩ High-Side MOSFET
  • 146 μA Operating Quiescent Current and
    2 μA Shutdown Current
  • 100 kHz to 2.5 MHz Fixed Switching Frequency
  • Synchronizes to External Clock
  • Low Dropout at Light Loads with Integrated BOOT Recharge FET
  • Adjustable UVLO Voltage and Hysteresis
  • 0.8 V 1% Internal Voltage Reference
  • 8-Terminal HSOP with PowerPAD™ Package
  • –40°C to 150°C TJ Operating Range
  • Create a Custom Design using the TPS54540 with the WEBENCH® Power Designer

2 Applications

  • Industrial Automation and Motor Control
  • Vehicle Accessories: GPS, Entertainment
  • USB Dedicated Charging Ports and Battery Chargers
  • 12 V and 24 V Industrial, Automotive and Communications Power Systems

3 Description

The TPS54540 is a 42 V, 5 A, step down regulator with an integrated high side MOSFET. The device survives load dump pulses up to 45V per ISO 7637. Current mode control provides simple external compensation and flexible component selection. A low ripple pulse skip mode reduces the no load supply current to 146 μA. Shutdown supply current is reduced to 2 μA when the enable pin is pulled low.

Undervoltage lockout is internally set at 4.3 V but can be increased using the enable pin. The output voltage start up ramp is internally controlled to provide a controlled start up and eliminate overshoot.

A wide switching frequency range allows either efficiency or external component size to be optimized. Output current is limited cycle-by-cycle. Frequency foldback and thermal shutdown protects internal and external components during an overload condition.

The TPS54540 is available in an 8-terminal thermally enhanced HSOP PowerPAD™ package.

Device Information

PART NUMBER PACKAGE BODY SIZE
TPS54540 HSOP (8) 4,89mm x 3,9mm

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Simplified Schematic

TPS54540 simple_sch_lvsbx7.gif

Efficiency vs Load Current

TPS54540 frnt_page_eff_slvsbn0.gif

4 Revision History

Changes from A Revision (March 2014) to B Revision

  • Added the WEBENCH information in the Features, Detailed Design Procedure, and Device Support sectionsGo
  • Changed the Handling Ratings table To ESD Ratings tableGo
  • Changed VIN MIN Value From: 4.5 V To: VO + VDO, and added Note 1 in the Recommended Operating ConditionsGo
  • Deleted last graph: "5 V Start and Stop Voltage" from the Typical CharacteristicsGo
  • Updated text and added Equation 1 in the Low Dropout Operation and Bootstrap Voltage (BOOT) Go
  • Deleted text: "The start and stop voltage for a typical 5 V..." from the Low Dropout Operation and Bootstrap Voltage (BOOT) sectionGo
  • Changed Equation 7 and Equation 8. Go
  • Changed Equation 27 Go
  • Added new section: Minimum VINGo
  • Deleted 2 graphs named "Low Dropout Operation" from the Application Curves section Go

Changes from * Revision (May 2013) to A Revision

  • Added Device Information table, Recommended Operating Conditions table, Pin Configuration and Functions section, Handling Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section.Go
  • Changed the Electrical Characteristics Conditions From: VIN = 4.5 to 60 V To: VIN = 4.5 to 42 VGo
  • Changed the Operating: nonswitching supply current TEST CONDITIONS From: FB = 0.83 V To: FB = 0.9 VGo
  • Changed RT/CLK high threshold MAX value From: 1.7 V To: 2 V Go
  • Changed the title of graph "5 V Start and Stop Voltage" to include a link to the Low Dropout Operation section. Go
  • Changed the FBD, removed the Logic block and Shutdown signal from the OV comparatorGo
  • Changed VF = Forward Drop of the Catch Diode To: VD = Forward Drop of the Catch Diode Go
  • Deleted value TSW = 1 / Fsw from the list following Equation 2Go
  • Changed VB2SW = VBOOT + VF To: VB2SW = VBOOT + VDGo
  • Changed VBOOT = (1.41 x VIN - 0.554 - VF / TSW - 1.847 x 103 x IB2SW) / (1.41 + 1 / Tsw) To: VBOOT = (1.41 x VIN - 0.554 - VD x ƒSW - 1.847 x 103 x IB2SW) / (1.41 + ƒSW)Go
  • Deleted figure: "5V Start/Stop Voltage"Go
  • Added a title to Figure 23Go
  • Changed the section title From: Selecting the Switching Frequency To: Accurate Current Limit Operation and Maximum Switching FrequencyGo
  • Changed text in the Synchronization to RT/CLK terminal section From: "0.5 V and higher than 1.7 V" To: "0.5 V and higher than 2 V" Go
  • Changed Equation 33 From: (5.13V2 - 5 V2) To: 3.43 V2 - 3.3 V2)Go
  • Changed Figure 36, VOUT From: 200 mV/div To 100 mV/div Go
  • Changed Figure 38 , EN From: 1 V/div To: 2 V/div, VOUT From: 4 V/div To: 2 V/div, and Time = 2 ms/div To: Time = 20 ms/divGo
  • Changed Figure 39 , VOUT From: 4 V/div To: 2 V/divGo

5 Pin Configuration and Functions

HSOIC Package
(Top View)
TPS54540 powerpad.gif

Pin Functions

TERMINAL I/O DESCRIPTION
NAME NO.
BOOT 1 O A bootstrap capacitor is required between BOOT and SW. If the voltage on this capacitor is below the minimum required to operate the high side MOSFET, the output is switched off until the capacitor is refreshed.
VIN 2 I Input supply voltage with 4.5 V to 42 V operating range.
EN 3 I Enable terminal, with internal pull-up current source. Pull below 1.2 V to disable. Float to enable. Adjust the input undervoltage lockout with two resistors. See the Enable and Adjusting Undervoltage Lockout section.
RT/CLK 4 I Resistor Timing and External Clock. An internal amplifier holds this terminal at a fixed voltage when using an external resistor to ground to set the switching frequency. If the terminal is pulled above the PLL upper threshold, a mode change occurs and the terminal becomes a synchronization input. The internal amplifier is disabled and the terminal is a high impedance clock input to the internal PLL. If clocking edges stop, the internal amplifier is re-enabled and the operating mode returns to resistor frequency programming.
FB 5 I Inverting input of the transconductance (gm) error amplifier.
COMP 6 O Error amplifier output and input to the output switch current (PWM) comparator. Connect frequency compensation components to this terminal.
GND 7 – Ground
SW 8 I The source of the internal high-side power MOSFET and switching node of the converter.
Thermal Pad 9 – GND terminal must be electrically connected to the exposed pad on the printed circuit board for proper operation.

6 Specifications

6.1 Absolute Maximum Ratings(1)

over operating free-air temperature range (unless otherwise noted)
VALUE UNIT
MIN MAX
Input voltage VIN –0.3 45 V
EN –0.3 8.4
BOOT 53
FB –0.3 3
COMP –0.3 3
RT/CLK –0.3 3.6
Output voltage BOOT-SW 8 V
SW –0.6 45
SW, 10-ns Transient –2 45
Operating junction temperature, TJ –40 150 °C
Storage temperature, TSTG –65 150 °C
(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.

6.2 ESD Ratings

VALUE UNIT
VESD (1) Human Body Model (HBM) ESD Stress Voltage (2) ±2000 V
Charged Device Model (HBM) ESD Stress Voltage (3) ±500 V
(1) Electrostatic discharge (ESD) to measure device sensitivity and immunity to damage caused by assembly line electrostatic discharges into the device.
(2) Level listed above is the passing level per ANSI/ESDA/JEDEC JS-001. JEDEC document JEP155 states that 500V HBM allows safe manufacturing with a standard ESD control process. terminals listed as 1000V may actually have higher performance.
(3) Level listed above is the passing level per EIA-JEDEC JESD22-C101. JEDEC document JEP157 states that 250V CDM allows safe manufacturing with a standard ESD control process. terminals listed as 250V may actually have higher performance.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
VIN Supply input voltage (1) VO + VDO 42 V
VO Output voltage 0.8 41.1 V
IO Output current 0 5 A
TJ Junction Temperature –40 150 °C
(1) See Equation 1

6.4 Thermal Information

THERMAL METRIC(1)(2) TPS54540 UNIT
DDA (8 PINS)
θJA Junction-to-ambient thermal resistance (standard board) 42.0 °C/W
ψJT Junction-to-top characterization parameter 5.9 °C/W
ψJB Junction-to-board characterization parameter 23.4 °C/W
θJCtop Junction-to-case(top) thermal resistance 45.8 °C/W
θJCbot Junction-to-case(bottom) thermal resistance 3.6 °C/W
θJB Junction-to-board thermal resistance 23.4 v
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
(2) Power rating at a specific ambient temperature TA should be determined with a junction temperature of 150°C. This is the point where distortion starts to substantially increase. See power dissipation estimate in application section of this data sheet for more information.

6.5 Electrical Characteristics

TJ = –40°C to 150°C, VIN = 4.5 to 42 V (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SUPPLY VOLTAGE (VIN TERMINAL)
Operating input voltage 4.5 42 V
Internal undervoltage lockout threshold Rising 4.1 4.3 4.48 V
Internal undervoltage lockout threshold hysteresis 325 mV
Shutdown supply current EN = 0 V, 25°C, 4.5 V ≤ VIN ≤ 42 V 2.25 4.5 μA
Operating: nonswitching supply current FB = 0.9 V, TA = 25°C 146 175
ENABLE AND UVLO (EN TERMINAL)
Enable threshold voltage No voltage hysteresis, rising and falling 1.1 1.2 1.3 V
Input current Enable threshold +50 mV –4.6 μA
Enable threshold –50 mV –0.58 –1.2 –1.8
Hysteresis current –2.2 –3.4 –4.5 μA
VOLTAGE REFERENCE
Voltage reference 0.792 0.8 0.808 V
HIGH-SIDE MOSFET
On-resistance VIN = 12 V, BOOT-SW = 6 V 92 190 mΩ
ERROR AMPLIFIER
Input current 50 nA
Error amplifier transconductance (gM) –2 μA < ICOMP < 2 μA, VCOMP = 1 V 350 μMhos
Error amplifier transconductance (gM) during soft-start –2 μA < ICOMP < 2 μA, VCOMP = 1 V, VFB = 0.4 V 77 μMhos
Error amplifier dc gain VFB = 0.8 V 10,000 V/V
Min unity gain bandwidth 2500 kHz
Error amplifier source/sink V(COMP) = 1 V, 100 mV overdrive ±30 μA
COMP to SW current transconductance 17 A/V
CURRENT LIMIT
Current limit threshold All VIN and temperatures, Open Loop(1) 6.3 7.5 8.8 A
All temperatures, VIN = 12 V, Open Loop(1) 6.3 7.5 8.3
VIN = 12 V, TA = 25°C, Open Loop(1) 7.1 7.5 7.9
THERMAL SHUTDOWN
Thermal shutdown 176 °C
Thermal shutdown hysteresis 12 °C
TIMING RESISTOR AND EXTERNAL CLOCK (RT/CLK TERMINAL)
Switching frequency range using RT mode 100 2500 kHz
fSW Switching frequency RT = 200 kΩ 450 500 550 kHz
Switching frequency range using CLK mode 160 2300 kHz
RT/CLK high threshold 1.55 2 V
RT/CLK low threshold 0.5 1.2 V
(1) Open Loop current limit measured directly at the SW terminal and is independent of the inductor value and slope compensation.

6.6 Timing Requirements

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ENABLE AND UVLO (EN TERMINAL)
Enable to COMP active VIN = 12 V, TA = 25°C 540 µs
INTERNAL SOFT-START TIME
Soft-Start Time fSW = 500 kHz, 10% to 90% 2.1 ms
Soft-Start Time fSW = 2.5 MHz, 10% to 90% 0.42 ms
HIGH-SIDE MOSFET
On-resistance VIN = 12 V, BOOT-SW = 6 V 92 190 mΩ
TIMING RESISTOR AND EXTERNAL CLOCK (RT/CLK TERMINAL)
Minimum CLK input pulse width 15 ns
RT/CLK falling edge to SW rising edge delay Measured at 500 kHz with RT resistor in series 55 ns
PLL lock in time Measured at 500 kHz 78 μs

6.7 Typical Characteristics

TPS54540 C025_SLVSBN0.png
Figure 1. On Resistance vs Junction Temperature
TPS54540 D027_SLVSDP8.gif
Figure 3. Switch Current Limit vs Junction Temperature
TPS54540 C026_SLVSBN0.png
Figure 2. Voltage Reference vs Junction Temperature
TPS54540 C028_SLVSBX7.png
Figure 4. Switch Current Limit vs Input Voltage
TPS54540 C029_SLVSBN0.png
Figure 5. Switching Frequency vs Junction Temperature
TPS54540 C031_SLVSBN0.png
Figure 7. Switching Frequency vs RT/CLK Resistance
High Frequency Range
TPS54540 C033_SLVSBN0.png
Figure 9. EA Transconductance During Soft-Start vs Junction Temperature
TPS54540 C035_SLVSBN0.png
Figure 11. EN Terminal Current vs Junction Temperature
TPS54540 C037_SLVSBN0.png
Figure 13. EN Terminal Current Hysteresis vs Junction Temperature
TPS54540 C039_SLVSBN0.png
Figure 15. Shutdown Supply Current vs Junction Temperature
TPS54540 C041_SLVSBN0.png
Figure 17. VIN Supply Current vs Junction Temperature
TPS54540 C043_SLVSBN0.png
Figure 19. BOOT-SW UVLO vs Junction Temperature
TPS54540 C045_SLVSBX7.png
Figure 21. Soft-Start Time vs Switching Frequency
TPS54540 C030_SLVSBN0.png
Figure 6. Switching Frequency vs RT/CLK Resistance
Low Frequency Range
TPS54540 C032_SLVSBN0.png
Figure 8. EA Transconductance vs Junction Temperature
TPS54540 C034_SLVSBN0.png
Figure 10. EN Terminal Voltage vs Junction Temperature
TPS54540 C036_SLVSBN0.png
Figure 12. EN Terminal Current vs Junction Temperature
TPS54540 C038_SLVSBN0.png
Figure 14. Switching Frequency vs VSENSE
TPS54540 C040_SLVSBX7.png
Figure 16. Shutdown Supply Current vs Input Voltage (VIN)
TPS54540 C042_SLVSBX7.png
Figure 18. VIN Supply Current vs Input Voltage
TPS54540 C044_SLVSBN0.png
Figure 20. Input Voltage UVLO vs Junction Temperature

 
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