Radio Power Distribution; Figure 3-12. Dc Voltage Routing Block Diagram (Uhf Range 1 And Uhf Range 2) - Motorola ASTRO XTL 1500 Detailed Service Manual

Theory of Operation: Radio Power Distribution
3.9

Radio Power Distribution

This section provides information on DC power distribution in XTL 1500 radios. In the XTL 1500
radio, power is distributed to two boards: the main board and control head.
Power for the radio is supplied by the vehicle's 12-V battery. When using a desktop adapter unit, an
external DC power supply can be connected to replace the vehicle's battery source.
A+ (referred to as incoming unswitched battery voltage) enters the radio through the rear RF power
amplifier connector (J0950) and is the main entry for DC power. The second path, through J2, pin 25,
provides ignition sense to optionally inhibit radio turn-on when the ignition switch is off. This feature
is programmable through the CPS.
When the control-head On/Off knob is turned on, the three 9.3-V regulators power on the controller
section, the RX/frequency generation unit (FGU) section, and the TX section. See
UHF Range 1 and UHF Range 2 bands or
bands.
Control Head
SWB+ 17
On/Off ATTiny13

Figure 3-12. DC Voltage Routing Block Diagram (UHF Range 1 and UHF Range 2)

6815854H01-A
J0401
A+ 19, 21
FET
Q0503
9.3V
Regulator
U0500
5V
Regulator
U0503
3.0V 2.85V
1.85V
Regulator Regulator
Regulator
U0962 U0501
U0507
Controller Section
20
IGN
Figure 3-13 on page 3-16
UNSW
A+
5V Circuit
VR0500, R0507
SW_A+
9.33V
Regulator
U0950
9.3V_FGU
9.3V_TX
5V
VCC5
Regulator
U0505
1.55V 3V
3V
Regulator Regulator
Regulator
U0502 U6750 U6002
RX / FGU Section
Figure 3-12
for the VHF and 700-800 MHz
UWW_5V
J0402 J2
20, 22 24
9.3V
9.3V
Regulator
Regulator
U5570
U0951
KEYED_9.1_EN
DRV_9.3V
Switch
GPIO
TX Section
18 25
June 15, 2005
3-15
for the
J0950
SWB+