Hytera TC-508 - Battery Save; Busy Channel Lockout

TC-508 Service Manual
18
LDO
U604
LDO
U602
LDO
U606
V_BAT
TX_CTL
SAVE
VT
VR SW
Q604
Q305
V_SAVE
V
R
VCC
VDD
5V
RF_MUTE
Figure 6
Power Supply Section: the 7.4V battery voltage is converted to 5V via DC-DC module U604, and further
converted via LDO U602 to 3V including two channels: VCC and VDD. VCC powers CPU and VDD
powers PLL circuit. The 5V voltage will be converted via LDO U606 to 4.5V including two channels: VT
and V-SAVE. V-SAVE powers VCO circuit and VT powers TX circuit. Finally, V-SAVE together Q604 and
Q305 are used to control VR, which powers RX circuit.