B+ Routing For 900 Mhz Band Main Board; Figure 3.5-1.B+ Routing For 900Mhz Main Board - Motorola ASTRO XTS 2500 Service Manual

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3.5.4 B+ Routing for 900 MHz Band Main Board

Figure 3.5-1

Raw B+ (7.5V) from the battery enters the radio through a 3-contact connector (B500). From B500 it

is routed through a ferrite bead (E500) to the fuse (F500) where RAW_B+ is distributed to the

transmitter and the RF section is supplied by RFSW_B+.

UNSW_B+ provides power to the following:

• the mechanical switch (S501)

• the radio's LED (D501)

and the voltage regulator (U702); then routes through the connector (J601, pin 3). U702 will be

discussed in the B+ and +5V routing for the voice encoder (vocoder) and controller (VOCON)

During the transmit mode, UNSW_B+ routes through a ferrite bead (E101) to the Power Control IC

(PCIC) (U102), the RF driver (U101), through another ferrite bead (E102) to the final power amplifier

(Q101). UNSW_B+ also routes through the Field Effect Transistor (FET) switch (Q702) where it

becomes SW_B+. SW_B+ powers a 5V linear regulator (U500), which supplies 5V to the PCIC

During the receive mode, the linear regular (U500) provides 5V to the mixer (U1) and the ABACUS

III IC (U401). U500 also provides 5V to the Frequency Generation Unit's (FGU) FracN (U201) and

August 16, 2007

and the appropriate schematic diagram in the back of this manual.

Ferrite Bead

TX Linear 5V

Figure 3.5-1. B+ Routing for 900MHz Main Board

900 MHz Radio Power: B+ Routing for 900 MHz Band Main Board

6816985H01-B