New Quarter Brick DC-DC Converters Come with 3000 VAC Reinforced I/O Insulation

Press Release Summary:

Minimax Quarter Brick DC-DC Converters now includes MTQZ50 and the MTQZ75 series models with input voltages of 72(43-101) VDC and 110(66-160) VDC. Converters come with overload /voltage/temperature/short circuit protection and remote On/Off, output voltage trim and output sensing. Meeting EN 50121-3-2, EN 50155 and UL/cUL/IEC/EN 60950-1 standards, units deliver an efficiency of up to 92%. MTQZ50 and the MTQZ75 converters are designed for advanced railway applications.

Original Press Release:

MINMAX Releases MTQZ50 and MTQZ75 Series of Converters for Advanced Railway Applications

The new range of industrial standard quarter brick DC-DC converters are approved to meet demanding railway applications

Taiwan-based power solution provider, MINMAX Technology has released its new range of industry standard quarter brick DC-DC converter modules — the MTQZ50 and the MTQZ75 — specifically designed for advanced railway applications.

MINMAX's next generation DC-DC converter modules, the MTQZ50 and the MTQZ75, conform to railway emission standard EN 50121-3-2, as well as railway safety standards EN50155 and IEC 60571. In addition, the new DC-DC converters also adhere to vibration and shock standards specified by EN 61373, environmental standards IEC/EN 60068-2-1,2,30, and fire protection standards EN45545-2.

The MTQZ50 and MTQZ75 DC-DC converter series, comprising of 8 models, integrate an I/O isolation of 3000VAC, offering ultra-wide input voltage ranges of 72 (43-101 VDC) and 110 (66-160VDC) with outputs of 5V, 12V, 15V, and 24V.

The next generation DC-DC converters, providing a high-efficiency level of up to 92%, incorporate cutting-edge features like remote on/off control, remote sense, output voltage trim, overload / voltage / temperature protection circuits, and convection cooled ambient temperatures.

EN50155 (IEC 60571) Approved

MINMAX's industrial standard quarter brick DC-DC converter modules, the MTQZ50 and the MTQZ75 series, comply with the specification requirements of international railway certification “EN50155 (IEC 60571): Railway Application Electronic Equipment Used on Rolling Stock.” The certification covers humidity, cooling, dry heat, and damp heat tests, mechanical requirement tests, Electromagnetic Compatibility (EMC) tests, insulation tests, rugged environmental tests, and I/O voltage isolation tests.

EN50155 Railway Certification Input Voltage Specification

As required by the EN50155 Railway Certification, MINMAX's railway certified MTQZ50 and MTQZ75 DC-DC converters draw power directly from the train’s battery power source, operating in the same range as the storage battery voltage without the requirement of any additional voltage stabilizing device.

Further, the industry-leading DC-DC converters cover input ranges, voltage spikes, transients, and brown-outs specified by the EN50155 standard for railway electronic equipment system, integrating the capacity to withstand input voltage drops of 0.6VN for 100 ms, and over-voltage surges of 1.4VN for 1s, with tight insulation to ensure safety. 

EN50155-Compliant Voltage Isolation

The MTQZ50 and MTQZ75 series of industrial standard quarter brick DC-DC converters conform to the 3000 VAC I/O isolation requirements of EN50155 Railway Certification. The 3KVAC I/O isolation with reinforced insulation presents a strong electrical barrier, which protects sensitive circuits from noise, power bus fluctuations, electromagnetic disturbances, electric shocks, surges, transient voltage spikes, mechanical damages, insulation breakdown of power architectures, and shorts between the ground loop, air gaps, PCB tracks, and arcing.

Product Overview


The high-performance MTQZ50 series of 50W DC-DC converters are especially designed for critical railway applications. Consisting of 8 models, the series is available in traditional railway input voltages of 72(43-101) VDC and 110(66-160) VDC. The MTQZ50 converter modules, incorporating an advanced circuit topology, provide a high-efficiency level of up to 92%. Product features include overload and over-temperature protection, reinforced insulation, remote On/Off control, as well as under-voltage shutdown. 


The MINMAX MTQZ75 series of industrial standard quarter brick 75W DC-DC converters are available in input voltages of 72(43-101) VDC and 110(66-160) VDC. The next generation DC-DC converter series integrates high-grade features, such as reinforced insulation, overload and over-temperature protection, under-voltage shutdown, as well as remote On/Off control. The high-performance series, specifically designed for complex railway applications, provides efficiency of up to 92%. 

Key Features of MINMAX MTQZ50 and MTQZ75 Series of Industrial Standard Quarter Brick DC-DC Converters

  • Industrial Standard Quarter Brick Package
  • Wide Input Voltage Range
  • High Efficiency up to 92%
  • I/O Isolation 3000 VAC with Reinforced Insulation
  • No Min. Load Requirement
  • Overload /Voltage/Temperature/Short Circuit Protection
  • Remote On/Off, Output Voltage Trim, Output Sensing
  • Vibration and Shock meets EN 61373
  • Cooling, Dry & Damp Heat Test meet IEC/EN 60068-2-1,2,30
  • Fire Protection Test meets EN 45545
  • Railway EMC Standard meets EN 50121-3-2
  • Railway Certified meets EN 50155 (IEC 60571)
  • UL/cUL/IEC/EN 60950-1 Safety Approval & CE Marking

MINMAX's MTQZ50 and MTQZ75 series of industrial standard quarter brick DC-DC converters, backed by a 3-year warranty, is Reach compliant, RoHS compliant, and conflict mineral free.

For more information about the MINMAX MTQZ250 and MTQZ275 series, please visit

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