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Interpreting Complex Data Sheet Specifications—Part V

In our fifth blog on interpreting complex data sheets, we turn to safety specifications. Many certifications listed on data sheets require rigorous testing—especially for the medical and railway industries. Data sheets are required to indicate all new certifications, testing procedures, special model numbers and designations, which adds to their length but provides a lot of useful information for end-users.

Let’s take a closer look at this trend through the lens of medical and railway, which are the two industries most heavily impacted by increased safety regulations:



Avoiding EMI In Medical Equipment. The medical industry has many standards related to leakage current, EMI resistance and voltage isolation—all of which must be avoided in machines and devices that come into direct contact with patients. In addition, the close proximity of equipment in hospitals increases the risk of noise interference, which could cause medical devices to work incorrectly at a critical time. Safety specifications, particularly ones related to EMI, therefore ensure power supplies pose no risk of interference. mount—and more.

Some specific examples include:

  • IEC-60601-1: the technical standards for medical electrical equipment in terms of safety and performance
  • 5000 Vac Isolation: a standard stipulating 1000 V more than the required isolation for IEC 60601-1
  • 2 X MOPP: the isolation, creepage and insulation requirements for medical products coming into contact with patients
  • Standards related to low leakage currents under 75 uA

Protecting Train Passengers. Power supplies used in railway applications also have their fair share of standards. Consider the EN 45545-2, which specifies how materials used on trains must be fire-tested, or the EN 50155, which outlines the specifications of electronic equipment used on railcars. The EN 50155 also requires power supplies to pass various tests related to electrical insulation, power surges, ESD and voltage transients—all of which are intended to protect the passengers onboard.

Additionally, the railway industry requires its own special input voltage range of 43 to 160 V, which doesn’t exist for other applications. To account for this, Polytron and other power supply manufacturers have had to add more models to their product portfolios.

Effect On Data Sheets. Because of the increase in safety specifications and, in many cases, the addition of new products that comply with these standards, data sheets have become longer. While on the one hand, this trend has complicated data sheets, the addition of these details makes data sheets much more useful for customers who require power supplies for medical and railway applications.