TRANSCEIVER 400 MHz MTP700 Portable Radio / Detailed Service Manual 4.1 - 21
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 4.1-11
Figure 4.1-11 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 and the SWB+ current limit regulator. RAW_B+ is routed via F200 (Fuse) becoming
FUSED_B+, which is used by the Audio PA, the 3.3V Switching Regulator and the SWB+ switch for the TX
Driver bias circuit.
-
TXPA
5V_RF
PWM1_1.8V
V1_3V
GCAP3
RA W _B+
5.5V_RF
7.2V BATTERY
VREF2_2.775V
V3_2.775V
VTS_2.3V
VREF2_2.775V_DIG
V4_2.775V
VREF1_2.775V
FUSED _B+
SW B +
V3_2.775V_DIG
V4_LNODCT
LC Filter
VREF1
PWM 2
VIB
V3
PWM 1
V1
LC Filter
V2
VREF2
LC Filter
LC Filter
DSC
V4
(with Pass
Transistor)
VREF3
VSIM
PA_B+
LC Filter
LC Filter
LC Filter
FUSE
MOS_SW
5.5V LIN REG
3.3V SW REG
MOS_SW
MOS_SW
SIDE_CONNECTOR_SWB+
BOTTOM_CONNECTOR_SWB+
AUDIO PA
CORE
ESCORT / TXVCO
REDCAP, DISPLAY, FLASH, SRAM, I/O-Section
Serial VCC for WPIC+
LNODCT
RFCU, RXU, TXPA, TXFE
AND GATE for TCXO_WARP
TX/RX-_LED
Backlight_LED
TS-REF
ADC_INPUT
LNODCT_RFOUT, RF PA bias circuit, VCC for
Charge Pumps WPIC+, 2ndLO_PLL_IC, ESCORT
BATTERY_Interface_Circuitry
TXPA_Driver bias circuit
SOFT_TURN_OFF
LC Filter
-
TXPA
5V_RF
PWM1_1.8V
V1_3V
GCAP3
RA W _B+
5.5V_RF
7.2V BATTERY
VREF2_2.775V
V3_2.775V
VTS_2.3V
VREF2_2.775V_DIG
V4_2.775V
VREF1_2.775V
FUSED _B+
SW B +
V3_2.775V_DIG
V4_LNODCT
LC Filter
VREF1
PWM 2
VIB
V3
PWM 1
V1
LC Filter
V2
VREF2
LC Filter
LC Filter
DSC
V4
(with Pass
Transistor)
VREF3
VSIM
PA_B+
LC Filter
LC Filter
LC Filter
FUSE
MOS_SW
5.5V LIN REG
3.3V SW REG
MOS_SW
MOS_SW
SIDE_CONNECTOR_SWB+
BOTTOM_CONNECTOR_SWB+
AUDIO PA
CORE
ESCORT / TXVCO
REDCAP, DISPLAY, FLASH, SRAM, I/O-Section
Serial VCC for WPIC+
LNODCT
RFCU, RXU, TXPA, TXFE
AND GATE for TCXO_WARP
TX/RX-_LED
Backlight_LED
TS-REF
ADC_INPUT
LNODCT_RFOUT, RF PA bias circuit, VCC for
Charge Pumps WPIC+, 2ndLO_PLL_IC, ESCORT
BATTERY_Interface_Circuitry
TXPA_Driver bias circuit
SOFT_TURN_OFF
LC Filter
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