Motorola Pro Series Elite - 2.5 VHF Transmitter

VHF Transmitter 2-5
2.4.4 ModB/Vstby Supply
The supply to the ModB/Vstby pin varies depending on the conditions listed in Table 2-2
2.5 VHF Transmitter
The VHF transmitter, shown in Figure 2-5, contains five basic circuits:
• Power Amplifier
• Antenna Switch
• Harmonic Filter
• Antenna Matching Network
• Power Control Integrated Circuit (PCIC).
Table 2-2. ModB/Vstby Supply Modes
Condition Circuit Operation
Radio On Vdd supply voltage via CR411
Radio Off • Vdd turned off
• Q416 gate is pulled low by R462
• Q416 is switched on
• U410 supplies 3.2V to ModB/Vstby
Primary battery removed • Vdd turned off
• Q416 gate is pulled low by R462
• Q416 is switched on
• Li Ion battery provides 3.2V to ModB/Vstby
Flash Mode • Boot_Ctrl line pull low
• ModA & ModB goes low
• Processor in boot-strap mode
• Flashing enabled
Figure 2-5. Transmitter Block Diagram
PCIC
Antenna
PA
Driver
Vcontrol
Vcontrol
From VCO
Jack
Antenna Switch/
Harmonic Filter/
Matching Network
PA-Final
Stage