Theory of Operation
: Controller
3-27
3.2.2.1.3 External Switcher 5
The controller board uses an external TI regulator (TPS62110, U6505) to regulate to 5.4V. The
TPS62110 is a 1.5A capable synchronous step down converter. The output is adjusted using a
voltage divider to the feedback pin. The regulator is powered from SW_B+.
Figure 3-19.
illustrates
the SW5 circuitry. The SW5 circuit also includes or-gate logic that facilitates implementation of
current saving PFM mode when the radio is in standby mode.
Figure 3-19. 5V Switched Power Supply
APX 3000 has Pulse Switching option.
Mode 1: Pulse Frequency Modulation (PFM). A relatively noisy but highly efficient pulsing mode for
Switched power supplies.
Mode 2: Pulse Width Modulation (PWM). Pulsing mode that is cleaner than PFM, used when risk of
RF interference is present which includes both transmit and receive radio modes.
Table 3-4. Pulse Switching Combination
PA_SHTDN
5V_PWM_EN
SYN
MODE
0
0
0
PFM
0
1
1
PWM
1
0
1
PWM
1
1
1
PWM
L6504
C6566
C6567
V_SW_5
VIN
U6505
TPS62110
VOUT
EN
SYNC
C6565
SW_B+
BGAP_COMP
PA_SHTDN
5V_PWM_EN
C6549
Summary of Contents for Astro APX 3000
Page 1: ...APXTM TWO WAY RADIOS APX 3000 DETAILED SERVICE MANUAL ...
Page 2: ......
Page 4: ...Notes ...
Page 6: ...vi Document History Notes ...
Page 10: ...x Table of Contents Notes ...
Page 12: ...xii List of Tables Notes ...
Page 18: ...xviii List of Figures Notes ...
Page 22: ...xxii CommercialWarranty Notes ...
Page 46: ...3 20 Theory of Operation Main Board Notes ...
Page 84: ...3 58 Theory of Operation Bluetooth Notes ...
Page 208: ...6 64 Troubleshooting Waveforms LF CW on Spectrum Analyzer Notes ...
Page 222: ...7 14 Troubleshooting Tables List of Board and IC Signals Notes ...
Page 282: ...8 60 Schematics Boards Overlays and Parts Lists Main Board Block UHF1 84012513001_A Notes ...
Page 390: ...8 168 Schematics Boards Overlays and Parts Lists Main Board Block VHF 84012512001_A Notes ...
Page 456: ...9 8 Debugging Fixture Powering up Covert Board Notes ...
Page 468: ...Glossary 10 Glossary Notes ...
Page 472: ...Index 4 Index Notes ...
Page 473: ......