1W Isolated Power Supply with Planar Transformer Reference Design


Design files


Isolated power supply is a main requirement in every industrial application where modules are connected to Programmable Logic Controllers (PLCs). Often, for those PLC modules, there is only limited space available, making the inclusion of large isolation transformers more difficult. TIDA-00688 provides isolated ±15-V and 5-V outputs in a very thin form factor with only 2.2-mm height on each side of the printed circuit board (PCB). This is achieved by integrating the transformer directly into the PCB. Furthermore, this reference design can be operated off a wide input voltage range of 14 V to 36 V and is all included in a small 25.4-mm * 43.8-mm form factor.

  • Integrated planar transformer
  • Wide-input voltage range of 14 V to 36 V (24-V nominal)
  • Three isolated outputs (1.7-mm clearance prim-sec coils, 0.71-mm prepreg (type 7628) prim-sec coils)
    • 15-V isolated, 30-mA ultra-low noise
    • -15-V isolated, 30-mA ultra-low noise
    • 5-V isolated, 40 mA
  • Ultra-thin profile < 2.2 mm
  • 6-mm thickness side-to-side (defined by ferrite)

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.

TIDUB83.PDF (1695 K)

Reference design overview and verified performance test data

TIDRJ99.PDF (359 K)

Detailed schematic diagram for design layout and components


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


Detailed overview of design layout for component placement


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


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

TIDRJA2.PDF (1068 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Buck converters (integrated switch)

TPS6217528V, 0.5A Step-Down Converter with SNOOZE Mode

Data sheet document-pdfAcrobat PDF open-in-new HTML
Isolated DC/DC converters & modules

LM50177.5-100V Wide Vin, 600mA Constant On-Time Synchronous Buck Regulator

Data sheet document-pdfAcrobat PDF open-in-new HTML
Linear & low-dropout (LDO) regulators

TPS7A30200-mA, low-noise, high-PSRR, negative, adjustable low-dropout voltage regulator with enable

Data sheet document-pdfAcrobat PDF open-in-new HTML
Linear & low-dropout (LDO) regulators

TPS7A49150-mA, 36-V, low-noise, high-PSRR, adjustable low-dropout voltage regulator with enable

Data sheet document-pdfAcrobat PDF open-in-new HTML

Technical documentation

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Type Title Date
* Design guide 1-W Isolated Power Supply With Planar Transformer Design Guide Jan. 21, 2016
Application note AN-2292 Designing an Isolated Buck (Fly-Buck) Converter (Rev. C) Dec. 17, 2014

Related design resources

Reference designs

TIDA-00129 1W Small Form Factor Power Supply with Isolated Dual Output for PLC I/O Modules TIDA-00237 Ultra-Small 1W, 12V-36V Iso Power Supply for Analog Prog Logic Controller Modules Reference Design

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