Product details


Vin (Min) (V) 4.5 Vin (Max) (V) 20 Vout (Min) (V) 0.6 Vout (Max) (V) 5 Iout (Max) (A) 40 Iq (Typ) (uA) 18000 Switching frequency (Min) (kHz) 200 Switching frequency (Max) (kHz) 1500 Features Adjustable Current Limit, Dynamic Voltage Scaling, Enable, Frequency Synchronization, PMBus, Phase Interleaving, Power Good, Pre-Bias Start-Up, Remote Sense, Synchronous Rectification, UVLO Adjustable, Voltage Margining Operating temperature range (C) -40 to 125 Regulated outputs (#) 2 Number of Phases 2 Rating Catalog open-in-new Find other Buck controllers (external switch)

Package | Pins | Size

VQFN (RHA) 40 36 mm² 6 x 6 open-in-new Find other Buck controllers (external switch)


  • Smart Power Mode in Factory Default (Compatible with TI Smart Power Stage CSD95378B and Pin-for-Pin Equivalent to TPS40425 – Non-Smart Power Mode in Factory Default)
  • Single Supply Operation: 4.5 V to 20 V
  • VOUT from 0.6 V
  • Dual or Multi-Phase Synchronous Buck Controller
  • Individual High-Speed AVS Interface
  • Fast Transient Response
  • Stackable up to Four Phases
    • 2-, 3-, or 4-Phase Interleaved Phase Shifts
    • Accurate Current Sharing
  • PMBus Interface Capability
    • Margining Up/Down with 2-mV Step
    • Programmable Fault Limit and Response
    • ±0.8% VOUT
    • Accuracy Current Monitoring
    • ±3°C External Temperature Monitoring In Smart Power Mode
    • Programmable UVLO ON/OFF Thresholds
    • Programmable Soft-Start Time, Turn-On Delay, and Turn-Off Delay
  • On-Chip Non-Volatile Memory (NVM) to Store Custom Configurations
  • 0.6-V Reference Voltage with 0.5% Accuracy from –40°C to 125°C
  • Programmable ƒSW from 200 kHz to 1.5 MHz
  • Supports Pre-biased Output
  • Differential Remote Sensing
  • Synchronization to an Extermal Clock
  • OC/OV/UV/OT Fault Protection
  • 40-Pin, 6 mm × 6 mm, QFN Package
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The TPS40428 device is a PMBus, synchronous buck, driverless controller. It operates in smart power mode with factory default settings, and it can operate in non-smart power mode after PMBus programing and power reboot. It can be configured for dual-output or 2-phase operation. It is also stackable up to 4 phases to support load current as high as 120 A. Interleaved phase shift for 2-. 3-, or 4-phases reduce the input and output ripples therefore reducing input and output capacitance.

The wide input voltage range can support 5-V and 12-V intermediate supply buses. The 0.5% reference voltage satisfies the need of precision voltage to the modern ASICs.

Using the PMBus standard, the TPS40428 device can program reference voltage, fault limit, UVLO threshold, soft-start time and turn-on and turn-off delay.

In addition, the device implements an accurate measurement system to monitor the output voltages, currents and temperatures for individual channels.

For all available packages, see the orderable addendum at the end of the data sheet.
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Technical documentation

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Type Title Date
* Datasheet TPS40428 Dual Output, 2-Phase, Stackable PMBus Synchronous Buck Driverless Controller with Adaptive Voltage Scaling (AVS) Bus datasheet (Rev. A) Jul. 22, 2014
Application note Multiphase Buck Design from Start to Finish, Part 1 (Rev. B) Apr. 07, 2021
Application note SMT Guidelines for Stacked Inductor (Inductor On Top) on Voltage Regulator IC Feb. 22, 2016
Application note MOSFET power losses and how they affect power-supply efficiency Jan. 26, 2016
Technical article Select the correct PMBus POL solution for your application Aug. 03, 2015
User guide Using the PWR594 EVM Dual Output DC/DC Analog with PMBus Interface Jul. 30, 2014

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Hardware development

document-generic User guide

The TPS40428EVM evaluation module (EVM) allows users to evaluate the TPS40428. The TPS40428 is a PMBus, synchronous buck, driverless controller. It can be configured for dual-output or 2-phase operation.  The TPS40428EVM is designed to demonstrate the TPS40428 in a typical, dual-output (...)

  • Vin: 7-14Vdc.
  • Vout1: 1.2Vdc / 20A, Vout2: 1.8Vdc / 20A.
  • Support PMBus programming.
  • Convenient test points for probing critical waveforms

Software development

Digital Power Software
FUSION_DIGITAL_POWER_DESIGNER Fusion Digital Power™  is the Graphical User Interface (GUI) used to configure and monitor select Texas Instruments digital power controllers and sequencer/health monitors. The application uses the PMBus protocol to communicate with the device over serial bus by way of a TI USB adapter.

Some of the tasks you can perform with the GUI include:

  • Turn on or off the power supply output, either through the hardware control line or the PMBus OPERATION command
  • Monitor real-time data. Items such as input voltage, output voltage, output current, temperature, and warnings/faults are continuously (...)

Design tools & simulation

SLUM434.ZIP (247 KB) - PSpice Model
PSpice® for TI design and simulation tool
PSPICE-FOR-TI — PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)

Reference designs

High Efficiency Dual 30A or Single 60A Digital Point-of-Load Reference Design
PMP9042 — The PMP9042 reference design combines digital TPS40428 controller with CSD95378B for a dual 30A or single 60A point-of-load . The design is size-optimized in a tiny 1"x1" area (25.4mm x 25.4mm). The PMP9042 demonstrates a  high efficiency, high density point-of-load with excellent thermal (...)
document-generic Schematic document-generic User guide
12Vin Dual-phase 50A Intelligent Power Module On Board Reference Design
PMP4482 PMP4482 is a full featured power module reference design including output UV/OV/OC and input voltage UV protection. It provides 0.7~2V output voltage with load current up to 50A by using TPS40428 and CSD95372. The built-in temperature and current sensors improve the accuracy and eliminate discrete (...)
document-generic Schematic document-generic User guide
High Efficiency, Power Density 1V/120A/30A/30A (4+1+1) w/ PMBus Reference Design for ASIC Processors
PMP11184 PMP11184 is a chipset solution for high current ASIC core rail regulation. It utilizes TPS53647 4-phase controller for 120A high current rail, which employs  DCAP+ control for fast transient response and TI's proprietary AutoBalance for tight steady and dynamic phase-to-phase current balance (...)
document-generic Schematic document-generic User guide
Xilinx Virtex UltraScale FPGA Power Solution with PMBus Reference Design
PMP9475 The PMP9475 12V-input reference design provides all the power supply rails necessary to power Xilinx's Virtex® UltraScale™ family of FPGAs in  a compact, highly efficient design.  This design uses several of TI's PMBus Point-Of-Load voltage regulators for ease of (...)
document-generic Schematic document-generic User guide
Complete PMBus Power System for Enterprise Ethernet Switches Reference Design
PMP10896 Complete PMBus power system for 3 ASIC/FPGA cores, DDR3 core memory, and auxiliary voltages found on high-performance Ethernet Switches.
document-generic Schematic document-generic User guide
High Density 160 A (210 A peak) 4 Phase DC-DC Buck Converter with PMBus Interface Reference Design
PMP9131 Fixed frequency voltage mode control is used for CPU, Memory and ASIC applications where a predictable frequency and/or synchrnization to an external clock is needed.  Four high-current synchronous power stages provide the high currents and low losses needed for these applications. Multi-phase (...)
document-generic Schematic document-generic User guide
60A 2-Phase PMBus Synchronous Buck Converter Reference Design
PMP10000 This design is for a 60A 2-phase Synchronous Buck Converter, incorporating the TPS40428 PMBus driverless PWM controller and the CSD95372B Smart Power Stage. The design accepts a 10V to 14V input, and provides a 1V at 60A output. The PMBus design enables programming, configuration, control (...)
document-generic Schematic document-generic User guide
Xilinx Kintex UltraScale FPGA Power Solution Reference Design with PMBus
PMP9444 The PMP9444 reference design provides all the power supply rails necessary to power Xilinx's Kintex UltraScale family of FPGAs.  It features two UCD90120A's for flexible power up and power down sequencing as well as voltage monitoring, current monitoring, and voltage margining through the (...)
document-generic Schematic document-generic User guide

CAD/CAE symbols

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VQFN (RHA) 40 View options

Ordering & quality

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