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  • TPSM843321 3.8V to 18V, 3A, Synchronous Buck Power Module With User Selectable Mode

    • SLUSG14 March   2025 TPSM843321

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  • TPSM843321 3.8V to 18V, 3A, Synchronous Buck Power Module With User Selectable Mode
  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  Fixed Frequency Peak Current Mode
      2. 6.3.2  Mode Selection
      3. 6.3.3  Voltage Reference
      4. 6.3.4  Output Voltage Setting
      5. 6.3.5  Switching Frequency Selection, Synchronization
      6. 6.3.6  Phase Shift
      7. 6.3.7  Enable and Adjusting Undervoltage Lockout
      8. 6.3.8  External Soft Start and Prebiased Soft Start
      9. 6.3.9  Power Good
      10. 6.3.10 Minimum On Time, Minimum Off Time, and Frequency Foldback
      11. 6.3.11 Frequency Spread Spectrum
      12. 6.3.12 Overvoltage Protection
      13. 6.3.13 Overcurrent and Undervoltage Protection
      14. 6.3.14 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Modes Overview
      2. 6.4.2 Heavy Load Operation
      3. 6.4.3 Pulse Frequency Modulation
      4. 6.4.4 Forced Continuous Conduction Modulation
      5. 6.4.5 Dropout Operation
      6. 6.4.6 Minimum On-Time Operation
      7. 6.4.7 Shutdown Mode
  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 Custom Design With WEBENCH® Tools
        2. 7.2.2.2 Output Voltage Resistors Selection
        3. 7.2.2.3 Choosing Switching Frequency
        4. 7.2.2.4 Soft-Start Capacitor Selection
        5. 7.2.2.5 Output Capacitor Selection
        6. 7.2.2.6 Input Capacitor Selection
        7. 7.2.2.7 Feedforward Capacitor CFF Selection
        8. 7.2.2.8 Maximum Ambient Temperature
      3. 7.2.3 Application Curves
    3. 7.3 Best Design Practices
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Third-Party Products Disclaimer
      2. 8.1.2 Development Support
        1. 8.1.2.1 Custom Design With WEBENCH® Tools
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
  12. IMPORTANT NOTICE

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Data Sheet

TPSM843321 3.8V to 18V, 3A, Synchronous Buck Power Module With User Selectable Mode

1 Features

  • Configured for a wide range of applications
    • 3.8V to 18V input voltage range
    • 0.6V to 12V output voltage range
    • Up to 3A continuous output current
    • 0.6V ±1% reference voltage (–40°C to 125°C)
    • Low quiescent current of 28uA (typical)
    • 70ns, 114ns minimum switching on, off-time
    • 8us maximum switching on-time
    • 98% maximum duty cycle
  • Ease of use and small design size
    • Peak current control mode with internal compensation
    • 200kHz to 2.2MHz selectable frequency
    • Synchronizable to an external clock (support phase shift): 200kHz to 2.2MHz
    • Selectable PFM / FCCM at light load condition
    • Selectable adjustable soft-start time / power-good indicator function
    • Good EMI performance with frequency spread spectrum and optimized pinout
    • Hiccup overcurrent (OC) limit for both high-side and low-side MOSFETs
    • Non-latched protections for overtemperature protection (OTP), overcurrent protection (OCP), overvoltage protection (OVP), undervoltage protection (UVP), and undervoltage lockout (UVLO)
    • Integrated bootstrap capacitor and inductor to support easy PCB layout
    • Operating junction temperature of –40°C to 125°C
    • 3.3mm × 4.5mm × 2mm QFN package
  • Create a custom design with the TPSM843321 using the WEBENCH® Power Designer

2 Applications

  • Medical and healthcare
  • Test and measurement
  • Building automation
  • Wired networking, wireless infrastructure
  • Distributed power systems with 5V and 12V input

3 Description

The TPSM843321 is a high-efficiency, high-power density, and easy-to-use, synchronous buck power module with high design flexibility. With operating input voltage ranging from 3.8V to 18V, the TPSM843321 is designed for systems powered from 5V, 12V power-bus rails. The device supports up to 3A continuous output current and 98% maximum duty cycle.

TPSM843321 uses fixed frequency peak current control with internal compensation for fast transient response and good line and load regulation. With the optimized internal loop compensation, the device eliminates the need for external compensation over a wide output voltage range and switching frequency.

Package Information
PRT NUMBERPACKAGE(1)PACKAGE SIZE(2)
TPSM843321RCJ (QFN-FCMOD, 9)3.3mm × 4.5mm
(1) For more information, see Section 10.
(2) The package size (length × width) is a nominal value and includes pins, where applicable.
TPSM843321 Simplified SchematicSimplified Schematic
TPSM843321 TPSM843321 Efficiency, VOUT = 5V, fSW = 1000kHz, FCCMTPSM843321 Efficiency, VOUT = 5V, fSW = 1000kHz, FCCM

TPSM843321 allows high design flexibility with wide supported switching frequency of 200kHz – 2.2MHz set by the RT/SYNC pin. The device has the option for pulse frequency modulation (PFM), forced continuous conduction modulation (FCCM) at light load condition, and adjustable soft-start (SS) time / power-good (PG) indicator with different configuration of the MODE pin.

TPSM843321 provides protection functions including thermal shutdown, input undervoltage lockout, cycle-by-cycle current limit, and hiccup short-circuit protection. TPSM843321 is available in a 9-pin, 3.3mm × 4.5mm, QFN package, and the pinout is available for single-layer PCB layout. The junction temperature is specified from –40°C to 125°C.

4 Pin Configuration and Functions

TPSM843321 9-Pin RCJ QFN-FCMOD, 3.3mm × 4.5mm Package (Top View)Figure 4-1 9-Pin RCJ QFN-FCMOD, 3.3mm × 4.5mm Package (Top View)
Table 4-1 Pin Functions
PINTYPE(1)DESCRIPTION
NAMENO.
EN1AEnable input to the converter. Driving EN high or leaving this pin floating enables the converter. An external resistor divider can be used to implement an adjustable VIN UVLO function.
FB2AOutput feedback input. Connect FB to the tap of an external resistor divider from the output to GND to set output voltage.
GND3GGround pin. Connected to the source of the low-side FET as well as the ground pin for the controller circuit. Connect to system ground and the ground side of CIN and COUT. The path to CIN must be as short as possible.
VOUT4POutput voltage. This pin is connected to the internal buck inductor. Connect the pin to the output load and connect external output capacitors between this pin and GND.
SW5PSwitching node. Do not place any external component on this pin or connect to any signal. The amount of copper placed on this pin must be kept to a minimum to prevent issues with noise and EMI.
VIN6PSupply input pin to internal LDO and high-side FET. Input bypass capacitors must be directly connected to this pin and GND.
MODE7AMode selection pin in light load condition and Power-Good / Soft-Start function. See Mode Selection for details.
SS/PG8AThis pin can be a soft-start function or Power-Good function depending on the mode pin configuration. If the soft-start function is selected, an external capacitor connected from this pin to GND defines the rise time for the internal reference voltage. If the Power-Good function is selected, this pin is an open drain power-good indicator, which is asserted low if output voltage is out of PG threshold, overvoltage, or if the device is under thermal shutdown, EN shutdown, or during soft start.
RT/SYNC9AFrequency select and external clock synchronization. A resistor to ground sets the switching frequency of the device. An external clock can also be applied to this pin to synchronize the switching frequency. See Section 6.3.5 for details.
(1) A = Analog, P = Power, G = Ground

 
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