May 28, 2008
6871620L01-C
2-2
Radio Power:
DC Power Routing–Transceiver Section
2.2
DC Power Routing–Transceiver Section
NOTE:
Refer to
Table 8.1, “List of Schematics and Boards Overlays,” on page 8-1
for a listing of
schematics showing the transceiver board DC power routing components.
Contact M1705, the B-plus assembly, connects the battery to the mainboard. Capacitors C20 and
C24 provide protection against momentary breaks at the B-plus connector due to contact bounce
when the radio is dropped.
VHF/ UHF:
Components C4, C6 and E101 forms a power-line filter for signal RAWB+, which
supplies battery voltage to the transmitter PA.
Transistor Q1301, controlled by signal FET_ENX from the MAKO IC, turns on XSWB+2, which
supplies to the 5-V linear regulator, U1 and TX_ALC block.
Fuse F901 and filter E1104, C1128 and C1129 supply fused B-plus to the VOCON section. In turn,
the VOCON section supplies VSW1, regulated 3.8 Vdc, from the MAKO (Audio, Power & Accessory
Interface IC) switching regulator to the XCVR. VSW1 supplies to the 3V linear regulators in the
transceiver section. The XCVR regulated power supplies are summarized in
.
2.3
DC Power Routing—VOCON Section
NOTE:
Refer to
Table 8.1, “List of Schematics and Boards Overlays,” on page 8-1
for a listing of
schematics showing the VOCON section DC power routing components.
, or unswitched B+, is routed to Q1301, Q1302 and the MAKO on the VOCON section.
The ON/OFF circuitry block is made up of Q9906, U9901, U9902, U9918, U9903 and Q9904. The
ON_OFF signal triggers the ON/OFF circuitry block which pulls the MECH_SW pin of the MAKO low,
enabling the routing of SWB+ to the XCVR and VOCON sections and the encryption module. SW B+
and UNSW B+ are also supplied to the encryption module through connector J701.
Transistor Q9906 is also under the control of the microcontroller unit (MCU) via V2_FIL from MAKO.
This allows the MCU detect the pressing of the ON/OFF button and to follow an orderly power-down
sequence when it senses that SWB+ is off. This sense is provided through MECH_SW.
Table 2-2. Transceiver Voltage Regulators
Ref.
Desig.
IC
Name
Output
Signal Name
Description
U1
LP2989
V5A
Regulated 5.0 Vdc
U2
LP3985
V3D
Regulated 3.0 Vdc digital
U3
LP3985
V3A
Regulated 3.0 Vdc analog for synthesizer
Summary of Contents for ASTRO XTSTM 4000
Page 1: ...COLOR CHORDS 7 ASTRO XTSTM 4000 Portable Radio Detailed Service Manual ...
Page 2: ......
Page 16: ...May 28 2008 6871620L01 C xiv Commercial Warranty Notes ...
Page 22: ...May 28 2008 6871620L01 C 1 6 Introduction Notes ...
Page 26: ...May 28 2008 6871620L01 C 2 4 Radio Power Notes ...
Page 56: ...May 28 2008 6871620L01 C 3 30 Theory of Operation Notes ...
Page 100: ...May 28 2008 6871620L01 C 6 8 Troubleshooting Waveforms Notes ...
Page 194: ...May 28 2008 6871620L01 C B 2 Motorola Service Centers Notes ...
Page 204: ...May 28 2008 6871620L01 C Glossary 10 Glossary Notes ...
Page 209: ......