TMPR4955AF datasheet(31/168 Pages) TOSHIBA

31 / 168 page

General Safety Precautions and Usage Considerations

3-11

3.4.2

Inspection Sequence

Do not insert devices in the wrong orientation. Make sure that the positive

and negative electrodes of the power supply are correctly connected.

Otherwise, the rated maximum current or maximum power dissipation

may be exceeded and the device may break down or undergo performance

degradation, causing it to catch fire or explode, resulting in injury to the

user.

When conducting any kind of evaluation, inspection or testing using AC

power with a peak voltage of 42.4 V or DC power exceeding 60 V, be sure to

connect the electrodes or probes of the testing equipment to the device

under test before powering it on. Connecting the electrodes or probes of

testing equipment to a device while it is powered on may result in electric

shock, causing injury.

(1) Apply voltage to the test jig only after inserting the device securely into it. When applying or

removing power, observe the relevant precautions, if any.

(2) Make sure that the voltage applied to the device is off before removing the device from the

test jig. Otherwise, the device may undergo performance degradation or be destroyed.

(3) Make sure that no surge voltages from the measuring equipment are applied to the device.

(4) The chips housed in tape carrier packages (TCPs) are bare chips and are therefore exposed.

During inspection take care not to crack the chip or cause any flaws in it.

Electrical contact may also cause a chip to become faulty. Therefore make sure that nothing

comes into electrical contact with the chip.

3.5

Mounting

There are essentially two main types of semiconductor device package: lead insertion and surface

mount. During mounting on printed circuit boards, devices can become contaminated by flux or

damaged by thermal stress from the soldering process. With surface-mount devices in particular,

the most significant problem is thermal stress from solder reflow, when the entire package is

subjected to heat. This section describes a recommended temperature profile for each mounting

method, as well as general precautions which you should take when mounting devices on printed

circuit boards. Note, however, that even for devices with the same package type, the appropriate

mounting method varies according to the size of the chip and the size and shape of the lead frame.

Therefore, please consult the relevant technical datasheet and databook.

3.5.1

Lead forming

Always wear protective glasses when cutting the leads of a device with

clippers or a similar tool. If you do not, small bits of metal flying off the cut

ends may damage your eyes.

Do not touch the tips of device leads. Because some types of device have

leads with pointed tips, you may prick your finger.

Semiconductor devices must undergo a process in which the leads are cut and formed before the

devices can be mounted on a printed circuit board. If undue stress is applied to the interior of a

device during this process, mechanical breakdown or performance degradation can result. This is

attributable primarily to differences between the stress on the device’s external leads and the

stress on the internal leads. If the relative difference is great enough, the device’s internal leads,

adhesive properties or sealant can be damaged. Observe these precautions during the lead-

forming process (this does not apply to surface-mount devices):

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