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Achieving 250 watts in a noiseless 2 inch by 4 inch package


CUS250M Series

for medical and industrial applications​

Achieving 250 watts in a noiseless 2" x 4" package

Ultra-compact single output CUS250M power supplies.

  • Up to 250W with convection and conduction cooling
  • Compact 2 x 4 inch footprint
  • Silent operation
  • Ideal for medical and many other applications

The series provides excellent flexibility for an easy design in and extraordinary standout features.

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First choice for system designers

  • Maximum flexibility
  • Impressive output power due to careful thermal management
  • Silent operation with convection and conduction cooling
  • High efficiency minimises running costs and environmental impact
  • Worry free system integration due to significant EMI margins
  • Flexible design-in with mechanical and signal options

The TDK-Lambda Difference

CUS250M punching above its weight & size

The CUS250M represents a significant advancement in power density. This can be simply demonstrated by its ability to deliver an exceptional 20W/in3.

This ensures

  • Maximum flexibility when embedding the CUS250M in your system.
  • It is good for the environment. You can minimise the size of the system enclosure thereby reducing the amount of material you consume.

In addition, the CUS250 can operate without fan cooling thereby reducing power consumption, as well as being completely silent.

Designed from the beginning to manage heat naturally

The CUS250M has been designed from the very start to be small. The series can deliver 250W with forced air or conduction cooling in ambient temperatures of up to 50°C or 200W at 30°C with convection cooling.

With so much power in such a small space, the CUS250M has been engineered to maximise its heat dissipation. Highly effective thermal management means that the CUS250M is able to operate reliably at higher temperatures and at higher output power levels, making it a truly class leading product.

Ultralow EMI emissions

All design validation and safety pre-approvals have been performed by in-house engineers at our state of the art EMC and DVT centres and backed up by independent regulatory approvals.

This is why the CUS250M has been designed to mitigate EMI radiation from the very start. By minimising emissions at the source we have managed to create a usable 10dB to 20dB margin to the toughest EN55011 Class B limits (Medical). This helps other subsystems to operate reliably and minimises the cost and risk of the complete system exceeding emission limits.

Choice of multiple mechanical options for flexible design-in

  • Open Frame: For simplicity and low cost
  • U channel: For improved thermal dissipation
  • Top Cover: To protect against accidental contact
  • Fan Cooling: For maximum power even under the toughest of environments


Flexible for a wide variety of industrial & medical applications

Owing to its small footprint, high power density, low EMI and the ability to operate at full load without forced air cooling, the small but powerful CUS250M is becoming the first choice for system designers, no matter what the application.


CUS250M at the heart of a medical system

The Needs

Medical systems first and foremost demand reliability and quality from every system element, including the power supply. The power supply is at the heart of the system and therefore needs to be trusted to operate safely and reliably whenever needed.

Our Solutions

By qualifying TDK-Lambda's power supplies to the latest medical standards we ensure that our customers can TRUST the CUS250M series to support their system.

Our power experts are on hand to assist you with selecting and integrating any one of our medical grade power supplies into your system.

We even demonstrate our belief in TDK-Lambda's quality and reliability by offering the CUS250M with a 5 year warranty.


Robust design for industrial applications

The Needs

Industrial technology covers an almost infinite range of applications. However they all share common requirements from their chosen power source. These include;

  • Safety: The PSU is the interface between the dangerous voltages of the mains supply and the low voltages used in the user/equipment interface.
  • Efficient: Increasing factory automation brings 24/7 365 day operation. Therefore running costs need to kept to a minimum.
  • Reliable: Often replacing failed power supplies costs more than the power supply itself (downtime, service engineer etc) and not forgetting the risk to reputation.

Our Solutions

By choosing the CUS250M, you know it is backed up by over 85 years of power experience. Every component has been individually selected and evaluated by a specialist TDK-Lambda components team.

All design validation and safety pre-approvals have been performed by in house engineers at our state of the art EMC and DVT centres and backed up by independent regulatory approvals.

Professional Audio & Video

Low EMI and audible noise supporting sensitive environments

The Needs

Professional audio and video systems cover many applications including capture, playback, production and lighting equipment. Any power supply supporting this equipment must operate reliably & silently to avoid any unwanted noise in the performance environment or on audio tracks. Just as important, invisible Electro-Magnetic noise that all electronic equipment emits, including power supplies, should not interfere with video or sound recording.

Our Solutions

The CUS250 has been designed from the very beginning to operate at full load silently. In addition the CUS250M has exceptionally low EMI emissions, not just meeting the EMI requirements but bettering them. This means worry free EMC.

It's small size and high power density and flexible mechanical options means it can be embedded almost anywhere.

Modified Standard & Power+ Solutions

The Needs

We understand that there is never a one size fits all solution. This could mean your application requires:

  • Non-standard voltages
  • Cable looms & connectors
  • Ruggedisation for shock, vibration, high G and outdoor environments

Or you just have an idea how to make integration easier or simpler.

Our Solutions

Our power experts are here to listen and discuss how best to realise your requirements, whether it is a modification to a standard product or a full custom design to your specification.

So before looking anywhere else, challenge us.

Technical Data

Power 250W
Output Voltage Options 12 & 24Vdc
Coming Soon 15, 18, 28, 36 & 48Vdc
Input Voltage Range 85 – 264Vac
Size : Open frame 50.8 x 101.6 x 39.5 mm
Size : U channel 64 x 119.2 x 39.5 mm
Size : Cover (/A) 64 x 119.2 x 43 mm
Size : Fan (/F) 64 x 119.2 x 60.6mm
Warranty 5 Years
Cooling Options ConvectionAir flowFanBaseplate
Efficiency: up to 94%

Additional Material

CUS250M overview video

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Take a closer look at the key features of our new CUS250M


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Whatever the demands of your application, whatever the production run, we're here to help. Give us a brief description of your needs and we'll be in touch.

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