Motorola Pro Series Elite - Chapter 2 Theory of Operation

2-1
Chapter 2 Theory of Operation
2.1 Introduction
This section provides a detailed theory of operation for the radio and its components.
2.2 Radio Power Distribution
Figure 2-1. DC Power Distribution Block Diagram
A Block diagram of the DC power distribution throughout the radio board is shown in Figure 2-1. A
7.5V battery (BATT 7.5V) supplies power directly to the electronic ON/OFF control as UNSWB+.
When the radio is turned on, MECH_SWB+ (ON/OFF volume control) will trigger the electronic ON/
OFF control (momentary-on path), then SWB+ is distributed. Vdda from 3.3V Vdda regulator will then
supply the microprocessor. Data is then sent to ASFIC_CMP to turn on GCB4(DAC). GCB4 will take
over the momentary-on path within 12ms. SWB+ will continue to support the whole board until the
radio is turned off.
Radio will be turned-off on two conditions;
1. MECH_SWB+ turned off
2. Low battery
When low battery level is detected by the microprocessor through both conditions above, it will store
the radio personality data to EEPROM before turning off.
SWB+
Fuse
Low Battery
Detect
Antenna
PCIC(ALC)
PA, Driver
LI Ion
3.5V
Reg.
Audio
ASFIC_CMP
VCOBIC
FRACTN
LVZIF
LCD
Driver
5V
RF. AMP, IF AMP
Ext. RX.
MECH.
SWB+
UNSWB+
TX.
R1
R5
R2
R3
Vdda
Vddd
MCU, MicroP, ROM
and EEPROM
Buffer (NU)
Led
Control
7.5V
Battery
Vdda
Regulator
Vddd
Regulator
5V
Regulator
Switch
On/Off Switch
Power
Amplifier