4.2 - 22 MTP700 Portable Radio / Detailed Service Manual TRANSCEIVER 800 MHz
GCAP3
The Global Control Audio Power (GCAP3) IC handles DC power distribution and audio
processing (ie audio amplification and analog-to-digital/digital-to-analog conversions). It
contains switching and linear regulators, audio preamplifiers, 13-bit CODEC, 14-channel
10-bit A/D Converter, 8-bit D/A Converter and interfaces with an external Audio Amplifier
for receive audio.
DC Power Distribution
See Figure 4.2-11
Figure 4.2-11 MTP700 DC Distribution
Several sections of the radio are connected directly to the battery, which supplies Raw_B+ and Fused_B+.
The radio operates at a low voltage of 5.8Vdc, nominal-level voltage of 7.2Vdc, and high-level voltage of
12Vdc. The battery is connected to J001 pins 3 (+) and J001 pin 1 (-). These pins supply the Raw_B+ to the
RF TX power amplifier. Raw_B+ is routed via F200 (Fuse) becoming Fused_B+, which is used by the Audio
PA.
LC
RF PA, TX PRE-DRIVER
CORE
KEYPAD LEDS - 6x BACKLIGHT LEDS - 4x
V1
PWM1_1.8V
V1_3V
GCAP 3
V2
FUSE
WDI
3.3V
SW REG.
AUDIO PA
RAW_B+_RF
VIB
7.2V BATTERY
REDCAP, DISPLAY, CE_BUS CONNECTOR,
SERIAL VCC FOR WPIC+, OPTION BD,
FLASH, SRAM
LNODCT, WPIC+, RF CKTS, RX_FRONT
END, TRANSMITTER
VREF1
V3
V4 (with
Pass Trans)
VREF2
V3_2.775V
V4_2.775V
VREF3
ESCORT IC, REF BUFFER, FEEDBACK
BUFFER
LC Filter
LC Filter
PWM 1
PWM 2
VREF2_2.775V
FUSED_B+
MOS
SW
SIDE_CONN_SW_B+
BOTT_CONN_SW_B+
MOS_SW
MOS_SW
.
AND GATE FOR TCXO_WARP
VREF2_2.775V
TS-REF
ADC INPUT
VTS_2.3V
DSC
VSIM
PA_B+
LC Filter
5.5V LIN REG. LC Filter
REGULATOR FOR TX_VCO, TX_BUFFER,
MAIN VCO
TX_Bias_Circuit
LNODCT RFOUTB, WPIC+ VCP, ESCORT CP
SW_B+
To Next Page
Loading...
