MAXREFDES1169: ±15V/75mA and ±7.5V/75mA output, ISO-BUCK DC-DC power module

The MAXREFDES1169 is a high-efficiency, iso-buck DC-DC power module based on the MAX17681. It accepts an input voltage range from 17V to 32V and adjusts the output voltage through primary-side feedback. The reference design provides four outputs: ±15V@75mA and ±7.5V@75mA, with a voltage regulation accuracy of ±10%. This iso-buck isolated power module is designed using the MAX17681 in a 10-pin (3mm x 2mm) TDFN package. The MAXREFDES1169 pin spacing complies with the Distributed Power Source Open Standards Alliance (DOSA) open standard for DC/DC module power supplies. Two transformer options are provided, one is from Wurth; the other is from Chinese transformer manufacturer HanRun, which is convenient for users to choose. The reference design provides 1500V electrical isolation.

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Key Features

• ±15V@75mA and ±7.5V@75mA output, output voltage ripple 180mV

• 17V to 32V input voltage range

• EN/UVLO input

• 200kHz switching frequency

• 89% peak efficiency

• Overcurrent protection

• No optocoupler design

• Output power up to 3.4W

• Thermal Protection

• Proven PCB layout

design resources

Design, build and test

This reference design introduces the MAXREFDES1169 hardware circuit design and provides detailed technical guidance for designing iso-buck converters using Maxim's MAX17681A current-mode controller. The power supply has been built and tested.