Motorola MTM800 FuG ET, Basic Service Manual

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Maintenance 6 - 3
Safe Handling of CMOS and LDMOS Devices
Complementary metal-oxide semiconductor (CMOS) and Laterally Diffused Metal Oxide
Semiconductor (LDMOS) devices are used in this family of terminals, and are susceptible to
damage by electrostatic or high voltage charges. Damage can be latent, resulting in failures
occurring weeks or months later. Therefore, special precautions must be taken to prevent device
damage during disassembly, troubleshooting, and repair.
Handling precautions are mandatory for CMOS/LDMOS circuits and are especially important in low
humidity conditions. DO NOT attempt to disassemble the terminal without first referring to the
following CAUTION statement.
CAUTION: This terminal contains static-sensitive devices. Do not open the terminal unless
you are properly grounded. Take the following precautions when working on this unit:
• Store and transport all CMOS/LDMOS devices in conductive material so that
all exposed leads are shorted together. Do not insert CMOS/LDMOS devices
into conventional plastic “snow” trays used for storage and transportation of
other semiconductor devices.
• Ground the working surface of the service bench to protect the CMOS/LDMOS
device. We recommend using the Motorola Static Protection Assembly (part
number 0180386A82), which includes a wrist strap, two ground cords, a table
mat, a floor mat, ESD shoes, and an ESD chair.
• Wear a conductive wrist strap in series with a 100k resistor to ground.
(Replacement wrist straps that connect to the bench top covering are
Motorola part number RSX4015_).
• Do not wear nylon clothing while handling CMOS/LDMOS devices.
• Do not insert or remove CMOS/LDMOS devices with power applied. Check all
power supplies used for testing CMOS/LDMOS devices to be certain that there
are no voltage transients present.
• When straightening CMOS/LDMOS pins, provide ground straps for the
apparatus used.
• When soldering, use a grounded soldering iron.
• If at all possible, handle CMOS/LDMOS devices by the package and not by the
leads. Prior to touching the unit, touch an electrical ground to remove any
static charge that you may have accumulated. The package and substrate may
be electrically common. If so, the reaction of a discharge to the case would
cause the same damage as touching the leads.
!