Medical Electronics - Circuits, Systems & Regulatory Compliance

Providing electronics designed for medical applications has a number of special challenges. Many of the requirements are related to safety and reliablility, and go well beyond the requirements of consumer electronics. Regulatory compliance to the IEC-60601 requirements becomes a large part of the architecture and design of the electronics in a medical system.

Although many medical systems use low frequency signal paths, many of the regulatory requirements demand RF and high speed transient design robustness to be compliant with the safety requirements. The need to deal with grounding, shielding, transient immunity are a big part of the "must have" within a medical product.

Effective Electrons has done end-to-end medical system electronics for a number of devices with success. More importantly, we have been brought in to redesign the electronics for clients who had already invested a sizable effort into a design that would not pass compliance testing.

Many of those efforts required a complete re-design in order to meet requirements. If the procduct cant pass complince testing it will not be able to be sold. Its that simple.

The below is a summary of those items common to all medical product testing.
In addition to these items there are a number of special considerations when a medical device is directly connected to a patient, and a number of other special considerations dependent upon the application for the device.

Conducted Emissions (CISPR 11 compliance)
Measures emissions conducted back onto the AC power mains.

Radiated Emissions (CISPR 11 compliance)
Measures unintentional RF emissions from the product in all operating modes.

Electrostatic Discharge Immunity (IEC 6100-4-2)
Contact discharge tests are run on all external conductive surfaces up to +/- 6KV, and air discharge to +/- 8KV.

Voltage Dips and Short Interruptions Immunity (IEC 61000-4-11)
Performed to determine immunity to fluctuations on AC power input

Power Line Harmonics (EN 61000-3-2)
Tests are for current injection of harmonics onto the AC power supplied to the product.

Power Line Flicker (EN 6100-3-3)
Tests for sensitivity to smaller (3-5%) power line variations using a stepped amplitude modulation.

Radio Frequency Immunity (IEC 61000-4-3) and RF Common Mode Immunity (IEC 61000-4-6)
Determines immunity to fields generated by intentional transmitters (radio, broadcast television, cell phones, etc.)

Electrical Fast Transient Burst Immunity (IEC 61000-4-4)
Determines immunity to switching and transient noise; applicable to both AC and DC inputs and any cabling greater than 3 meters.

Power Line Surge Immunity (IEC 61000-4-5)
Performed to determine immunity of product to switching and lightning-induced transients. Both differential mode and common mode tests are performed.

Power Frequency Magnetic Fields (IEC 61000-4-8)
Performed to determine immunity of product to low frequency (50, 60 Hz) magnetic fields.

For more information on help with medical electronics, contact us.

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