Dc Power Routing; Figure 2-1. Dc Power Distribution - Motorola APX 1000 Detailed Service Manual

2-2
Battery
7.5 Volts
(Nominal)
B+ from the battery is electrically switched to most of the radio, rather than routed through the On/
Off/volume control knob, S2 (APX 2000/ APX 4000/ APX 4000Li/ APX 1000 (900 MHz)); S3 (APX
2000/ APX 4000 (Two Knobs)). The electrical switching of B+ supports a keep-alive mode. Under
software control, even when the On/Off/volume control knob has been turned to the Off position,
power remains on until the MCU completes its power-down, at which time the radio is physically
powered down.
2.2

DC Power Routing

NOTE: Refer to
listing of schematics showing the transceiver board DC power routing components.
Connector M101, the B-plus assembly, connects the battery to the main board. Component E201
forms a power-line filter for signal DC_ RAW_B+, which supplies battery voltage to the transmitter
section. Fuse F200 and filter C202, L200, C203 supply fused B plus to the controller section.
In turn, the controller supplies VSW1 regulated 3.6 Vdc, 2.78 Vdc, and 1.85 Vdc. The
3.6 Vdc supplies regulator U201 and controls switch Q201 which supplies fuse B+ to regulator U200.
Regulator U201 supplies regulator U202. The 2.775 Vdc supplies regulator U202, Trident IC U702,
and 16.8 MHz crystal circuit. The 1.85 sets the logic level for the SPI and SSI data.
In addition, the main board also has four regulators 5 Vdc (U200), 3 Vdc (U201), 1.8 Vdc (U202) and
1.5 Vdc (U203). The 5 volt regulator supplies the FGU section, transmitter ALC and receiver back
end. The 3 volt regulator supplies dc for the receiver front ends, mixer, receiver back end and GPS.
The 1.8 volt regulator supplies dc for the receiver front end and mixer. The 1.5 volt regulator supplies
dc for the buffers in the FGU section.
M101 FB+
BATT
Fuse
RAW B+
5Vdc
1.85Vdc
5Vdc
3Vdc
3Vdc
1.8 Volts
1.8Vdc
1.5Vdc
2.8Vdc
1.5Volts
Keypad Board
5.4Vdc
3.3Vdc
3.3Vdc
2.8Vdc
2.8Vdc

Figure 2-1. DC Power Distribution

Table 8-1, "List of Transceiver Schematics and Board Overlays," on page 8-1
Main Board
PMOS
FB+
Switch
5.4Vdc
External SW
Audio PA
1.4Vdc
External SW
1.85Vdc
External LDO
3.6Vdc
1.875Vdc
1.55Vdc
2.775Vdc
2.775Vdc
2.8Vdc
3.0Vdc
5.4Vdc
3.3Vdc
3.6Vdc 5Vdc
5Vdc
2.775Vdc
5Vdc
1.85Vdc
Radio Power: DC Power Routing
SW_B+
External 3.6Vdc
SW
2.23Vdc
External
LDO
MAKO
SW2
2.23Vdc
LD02
2.23Vdc
LDO3
3.6Vdc
LD04
3.6Vdc
LD06
3.6Vdc
LD07
3.6Vdc
LD09
3.6Vdc
LDO10
5.4Vdc
VBUS1
5.4Vdc
VBUS2
SW_B+
LD08
for a