Motorola StarTAC 3000 - Safe Usage Guidelines

6/29/98 5
Theory of Operation
Special Logic Circuits
A brief description of special logic circuits
used in the StarTAC:
•
PAC IC —A triple 8 bit DAC that controls
the PA bias and internal charger
•
Internal Charger —The microprocessor is
capable of reading a Motorola Li Ion
battery with internal ROM to determine
optimum charging conditions. If no ROM
is detected, then the battery is charged as if
it were a NiCd or NiMH battery. The
internal charger is disabled during a call.
•
Vibrator Option —Used as a silent alert
option for incoming calls. This option is
controlled by the SNAP IC and a external
driver circuit.
•
RF Switch Circuit —An RF switch driver
and RF switch FET normally select the
internal antenna. The external RF
connection is selected if an antenna is
detected on the option connector.