4.1 - 16 THEORY OF OPERATION (TRANSCEIVER)
Controller Section
For the Controller Section Block Diagram see Figure 4.1-5 on page 4.1-9.
This section describes the related circuits as follows:
• DC Power Distribution and RESET
• Microprocessor and Host Memories
• SPI
•RS232/USB
• Terminal Audio System
•RTC
•GPS
• SIM card connectivity
•GPIOs
DC Power Distribution
Figure 4.1-6 DC Power Distribution Diagram
DC Power Input
The DC power of nominal 13.2 volts enters the terminal at connector J0301. Diode VR0300 acts as
protection against transients and wrong polarity of the supply voltage. The supply voltage is fed
directly to the RF PA, through the 3A fuse F0303 to the audio circuitry, through F0302 to the
expansion head and Enhanced Control Head, and through the 4A PCB fuse (F0301) to regulators
U0300, U0301, U0302, and the ON/OFF and VSTBY circuitry. The fuses protect the board from over
current in case of a short on the connector pins or circuit failure.
ABACUS
FracN
Expansion
Head
Controller
RF PA
Audio
I/O
VCOBIC
RX
-
VCO
FE + Mixer
IF
PATRIOT
FLASH
RAM
ADDAG
TX
Accessory
Connector
20
-
PI N
13,2V
A+
4.6V
VSF
5V
9,3V
9.3V
9.3V
Escort
TX
-
VCO
3V_DIG
Head D
5V
Regulator
LP2 951
Option
JAVELIN
3V_TX
U0307
MC33275
5V_TX
U0304
LP2951C
1.55 V
U0306
LP2 951 C
ON/OFF
Circuit
SW B+
U0302
LM2941
9.3V_TX
U0300
LM2941
3.3V_FN
U5321
LP2980
5V_FN
U5322
ADP3300
Digital_3.3V
U5103
LP2980
Analog_3.3V
U5102
LP2980
Ref.
Voltage
9.3V
U0301
LM2941
SW B+
3V_TX
3.3V_DIG
3 V
Regulator
LP2951
SW B+
Regulator
LP2941
5VD
U0303
78M05
9.3V
ON / OF F
9.3V_TX
13,2V
5V_TX
RTC
VSTBY
PC I C
3V_DIG
Fuse
F0303
Fuse
F0301
1.8 V
U1105
LP2985
3.3V_DIG
U0305
LP2 951 C
UCM
Option
GPS
Option
ON / OFF
Fuse
F0302
Q0305
9.3V
6866539D31.book Page 16 Tuesday, March 20, 2007 6:32 PM
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