Unregulated LLC module reference design for two-stage 54-V POL in data centers


Design files


This reference design is for two-stage power architecture for 54V to VCore voltage regulator module (VRM) powering CPUs, GPUs and DDR memory in 48-V rack power architecture in data centers. The First-stage is an unregulated LLC resonant converter with an integrated planar magnetic structure and fixed transformation ratio of 6:1. The LLC module uses the UCD3138a controller and CSD95490Q5MC smart power stage for secondary side synchronous rectifiers, and LMG1205 with EPC2045 GaN devices for the primary side. The LLC module delivers a continuous output power of 600W and 98.2% maximum efficiency while operating at a maximum frequency of 1 MHz. This is module provides a power density of 1700 W/in3. The Second-stage uses the VR13.HC TPS53k DCAP+ multiphase controllers and CSD9k NexFET smart power stages capable of delivering a continuous output current of 400A with maximum efficiency of 95.6%. The Two-Stages VRM can achieve a maximum efficiency over 94% at the TDP point with minimum overshoot and undershoot with fast load transients.

  • Wide input voltage range from 40 V to 60 V
  • Unregulated output voltage range from 6.6-V to 10-V
  • 75-A continous operating current capability
  • Over 98% system efficiency at 10-V, 25-A output
  • High power density of 1700 W/in3 in a 36 mm x 26 mm footprint
Output voltage options PMP22519.1
Vin (Min) (V) 40
Vin (Max) (V) 60
Vout (Nom) (V) 8
Iout (Max) (A) 75
Output Power (W) 600
Isolated/Non-Isolated Non-Isolated
Input Type DC
Topology Full Bridge- LLC

A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDT180.PDF (3611 K)

Test results for the reference design, including efficiency graphs, test prerequisites and more

TIDM585.PDF (193 K)

Detailed schematic diagram for design layout and components

TIDM586.PDF (489 K)

Complete listing of design components, reference designators, and manufacturers/part numbers

TIDM587.PDF (71 K)

Detailed overview of design layout for component placement

TIDM589.ZIP (5842 K)

Files used for 3D models or 2D drawings of IC components


Design file that contains information on physical board layer of design PCB

TIDM588.PDF (361 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Power stages

CSD95490Q5MC75A Synchronous Buck NexFET™ Smart Power Stage with DualCool Package

Data sheet: PDF | HTML
Digital power isolated controllers

UCD3138AUCD3138A Highly Integrated Digital Controller for Isolated Power

Data sheet: PDF | HTML
Half-bridge drivers

LMG12051.2-A, 5-A 90-V, half bridge gate driver with 5-V UVLO for GaNFET and MOSFET

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Test report Unregulated LLC Module Reference Design for Two-Stage 54-V POL in Data Centers May 06, 2020

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