MAXREFDES1294: 12VIN, Eight-output, Isolated DC-DC Power Supply Using the MAX13256


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The MAXREFDES1294 is an isolated DC-DC power supply that delivers four 24V outputs and four 12V outputs from a 12V supply voltage. It is designed for an industrial system which needs multiple isolated voltages from a 12V input voltage. The MAXREFDES1294 show the techniques using the H-bridge transformer driver to generate multiple isolated outputs. This document explains how the MAX13256 can be used to deliver four 24V outputs and four 12V outputs from a 12V supply voltage.

The MAX13256 is a small, high-performance transformer driver, ideal for isolated power delivery in the industrial or medical environments. The MAX13256 is an unregulated DC-DC circuit component, that is, it has no feedback to control the secondary voltage. For this reason, the MAX13256 can be used especially in the applications where the secondary power does not need tight regulation. Even when good regulation is requested, following a MAX13256 with a post regulator can still be a cost-competitive solution.

The MAX13256 H-bridge transformer driver provides a simple solution to make isolated power supplies up to 10W. The device drives a transformer’s primary coil with up to 300mA of current from a wide 8V to 36V DC supply. The transformer’s secondary-to-primary winding ratio defines the output voltage, which allows to select any isolated output voltage virtually.


  • Undervoltage Lockout
  • 2.5V to 5V Compatible Logic Interface
  • Internal or External Clock Source
  • Adjustable Overcurrent Threshold
  • Fault Detection and Indication
  • Overcurrent Limiting
  • Overtemperature Protection
  • Small 10-Pin TDFN Package (3mm x 3mm)



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PCB Layout


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Test Results


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Input Type Vin(Min) Vin(Max) Iout(Max) Single/Multiple Output Vout(V) Pout(W) Isolated/Non-Isolated Topology
DC 11.76 12.24 0.03 Multiple Output 24 4.56 Isolated H-Bridge


Input Type DC
Vin(Min) 11.76
Vin(Max) 12.24
Iout(Max) 0.03
Single/Multiple Output Multiple Output
Vout(V) 24
Pout(W) 4.56
Isolated/Non-Isolated Isolated
Topology H-Bridge

Maxim Devices (1)

Part Number Name Product Family Order Design kits and evaluation modules
MAX13256 36V H-Bridge Transformer Driver for Isolated Supplies Isolated Power Buy Now

Maxim Devices (1)

Part Number Product Family
Isolated Power
36V H-Bridge Transformer Driver for Isolated Supplies

Design Files (4)

Title Type Size Date
MAXREFDES1294 BOM XLSX 12KB 2021-12-15
MAXREFDES1294 PCB Layout PDF 1MB 2021-12-15
MAXREFDES1294 Schematic PDF 31KB 2021-12-15
MAXREFDES1294 Test Results PDF 135KB 2021-12-15
Date Type


(XLSX, 12KB)



(PDF, 1MB)


MAXREFDES1294 Schematic

(PDF, 31KB)


MAXREFDES1294 Test Results

(PDF, 135KB)

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