156-VAC - 440-VAC input magnetically resistant anti-tamper flyback reference design
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Key Document


This offline flyback reference design uses the UCC28740 controller to generate an isolated output (12 V at 1 A) from a wide AC input (156 VAC - 440 VAC). The design was developed to be resistant to large magnetic fields (200mT) near the transformer. The transformer, the frequency and modulation modes were optimized for improved magnetic resistance.

  • 156 VAC - 440 VAC input to an isolated output
  • Immune to DC magnetic tampering up to an external magnetic field of 200mT
  • Sendust Core Transformer and low switching frequency improve magnetic resistance

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(Output Voltage 1)
Vin (Min) (V)156
Vin (Max) (V)440
Vout (Nom) (V)12
Iout (Max) (A)1
Output Power (W)12
Input TypeAC
TopologyFlyback- Quasi Resonant

TI Devices (2)

Order samples, get tools and find more information on the TI products in this reference design.

Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
ATL431  2.5-V low-IQ adjustable precision shunt regulator  Voltage references  Sample & Buy View Design Kits & Evaluation Modules
UCC28740  Constant-voltage, constant-current Flyback controller Using Opto-Coupler Feedback  Offline & isolated DC/DC controllers & converters  Sample & Buy View Design Kits & Evaluation Modules

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
ATL431 Download Download
UCC28740 Download Download

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Technical documentation

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User guides (1)
Title Type Size (KB) Date
PDF 9607 15 Jan 2019
Design files (6)
Title Type Size (KB) Date
ZIP 149 15 Jan 2019
ZIP 805 15 Jan 2019
PDF 223 15 Jan 2019
PDF 192 15 Jan 2019
PDF 30 15 Jan 2019
PDF 148 15 Jan 2019

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