Figure 3-17. V_Sw_1.4 Switched Power Supply - Motorola APX 5000 Service Manual

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3.2.2.1.2 External Regulators: V_SW_1.4, V_SW_3.60
The controller board contains two TPS62050 regulators in order to regulate voltages of 1.4V and
3.6V. The TPS62050 is a synchronous step-down adjustable regulator. The switching regulator is
capable of sourcing 800mA. Its output can be adjusted by using a voltage divider tied to the feedback
pin. The regulators are powered from SW_B+.
regulator that illustrates the supporting circuitry for the TPS62050.
SW_B+
R6547
0
C6569
10UF
V_1.55
VCC_SW1.4_VIN
R6552
100K
R6554
0
R6558
165K
R6548
0
DNP

Figure 3-17. V_SW_1.4 Switched Power Supply

Figure 3-17 is the schematic for the V_SW_1.4
SW1V4_FB
C6582
6.8PF
U6507
TPS62050
8 4
EN
PG
5 9
FB
SW
6 2
LBI L6505
LBO
7 10UH
SYNC
Theory of Operation
V_SW_1.4
R6568
301K
C6570
330PF
C6584 C6586
10UF 4.7UF
: Controller