TMPR4937 datasheet(39/552 Pages) TOSHIBA

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3 General Safety Precautions and Usage Considerations

3-17

3.6.5

Strong electrical and magnetic fields

Devices exposed to strong magnetic fields can undergo a polarization phenomenon in their plastic material, or

within the chip, which gives rise to abnormal symptoms such as impedance changes or increased leakage

current. Failures have been reported in LSIs mounted near malfunctioning deflection yokes in TV sets. In such

cases the device’s installation location must be changed or the device must be shielded against the electrical or

magnetic field. Shielding against magnetism is especially necessary for devices used in an alternating magnetic

field because of the electromotive forces generated in this type of environment.

3.6.6

Interference from light (ultraviolet rays, sunlight, fluorescent lamps and

incandescent lamps)

Light striking a semiconductor device generates electromotive force due to photoelectric effects. In some cases

the device can malfunction. This is especially true for devices in which the internal chip is exposed. When

designing circuits, make sure that devices are protected against incident light from external sources. This

problem is not limited to optical semiconductors and EPROMs. All types of device can be affected by light.

3.6.7

Dust and oil

Just like corrosive gases, dust and oil can cause chemical reactions in devices, which will adversely affect a

device’s electrical characteristics. To avoid this problem, do not use devices in dusty or oily environments. This

is especially important for optical devices because dust and oil can affect a device’s optical characteristics as

well as its physical integrity and the electrical performance factors mentioned above.

3.6.8

Fire

Semiconductor devices are combustible; they can emit smoke and catch fire if heated sufficiently. When this

happens, some devices may generate poisonous gases. Devices should therefore never be used in close

proximity to an open flame or a heat-generating body, or near flammable or combustible materials.

3.7

Disposal of Devices and Packing Materials

When discarding unused devices and packing materials, follow all procedures specified by local regulations in

order to protect the environment against contamination.

TMPR4937 Datasheet(PDF) 39 Page - Toshiba Semiconductor