Motorola MTM800 User Manual page 51

THEORY OF OPERATION (TRANSCEIVER)
9V3 Linear Regulator U0301
Regulator U0301 is connected to the 13.2 volts supply voltage via PCB fuse. The output of this
regulator is controlled by the ON/OFF circuitry. When any of the signals RTC_ON_SW,
ON_OFF_CONTROL_SV, SOFT_TURN_OFF, IGNITION is at high level or EMERGENCY is at low
level the regulator is switched on via transistors Q0302, Q0301, Q0303. In addition, regulators
U0300 and U0302 are also switched on by the same signal. The output voltage of U0301 is set to
9.3 volts with resistors R0307 and R0308.
9V3_TX Linear Regulator U0300
Regulator U0300 is connected to the 13.2 volts supply voltage via PCB fuse. The output of this
regulator is controlled by the ON/OFF circuitry. When any of the signals RTC_ON_SW,
ON_OFF_CONTROL_SV, SOFT_TURN_OFF, IGNITION is at high level or EMERGENCY is at low
level the regulator is switched on via transistors Q0302, Q0301, Q0303. The output voltage of
U0300 is set to 9.3 volts with resistors R0305 and R0306.
SW B+ Current Limit Regulator U0302
Regulator U0302 is connected to the 13.2 volts supply voltage via PCB fuse. The output of this
regulator is controlled by the ON/OFF circuitry. When any of the signals RTC_ON_SW,
ON_OFF_CONTROL_SV, SOFT_TURN_OFF, IGNITION is at high level or EMERGENCY is at low
level the regulator is switched on via transistors Q0302, Q0301, Q0303. The output voltage of
U0302 is set far above the maximum possible input voltage with resistors R0303 and R0304 so that
this regulator acts as a current limiter for the EXT_SWB+ voltage on the 20 pin accessory connector.
5VD Linear Regulator U0303
Regulator U0303 gets its input voltage from the 9.3 volt regulator U0301. The output voltage 5VD is
fixed to 5 volts and is the input voltage for the regulators U0305 and U0306. The voltage 5VD is also
fed to the Enhanced Control Head.
5V_FN Linear Regulator U5322
Regulator U5322 gets its input voltage from the 9.3 volt regulator U0301. The output voltage 5V_FN
is fixed to 5 volts and is mainly used in the frequency generating unit (FGU).
3V3_FN Linear Regulator U5321
Regulator U5321 gets its input voltage from the 9.3 volt regulator U0301. The output voltage
3V3_FN is fixed to 3.3 volts and is mainly used in the frequency generating unit (FGU).
Analog_3V3 Linear Regulator U5102
Regulator U5102 gets its input voltage from the 9.3 volt regulator U0301. The output voltage
ANALOG_3V3 is fixed to 3.3 volts and is mainly used in the receiver section.
Digital_3V3 Linear Regulator U5103
Regulator U5103 gets its input voltage from the 9.3 volt regulator U0301. The output voltage
DIGITAL_3V3 is fixed to 3.3 volts and is mainly used in the receiver section.
3V_TX Linear Regulator U0307
Regulator U0307 gets its input voltage from the 9.3 volt regulator U0300. The output voltage 3V_TX
is fixed to 3 volts and is used in the transmitter TX_LOW section to supply the ADDAG and JAVELIN
IC.
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