Page
4.9
3 ~ TECHNICAL DESCRIPTION
The Power-off operation requires the On-Off switch to be turned off for more than 2 seconds. If the On-Off
switch is sensed going low by the DSP via the PWR_SENSE line, the DSP will save radio settings and then
lower the PWR_OFF line, thereby turning Q900 off.
4.6.2
Power Supplies
The following is a list of the SRP9100
power supplies and some of the devices and circuits they supply.
4.6.2.1 5V Regulator U900
This regulator can be powered down by a STBY signal from the PLA. Supplies RX_PSU and TX_PSU are
switched via Q903 and Q904. Circuits supplied by U900 are as follows.
•
Synthesiser reference oscillator, divider and phase modulator
•
VCO Varicap driver
•
Switched RX PSU to VCO output switch
•
Switched TX PSU to TX VCO enable/Rx VCO disable
•
Switched TX PSU to Transmit Buffer Amplifiers
•
Switched RX PSU to Receive front end and mixer
•
90MHz local oscillator Q402
4.6.2.2 5V Regulator U901
•
Transmit and receive VCO’s
•
PLL U701
•
Analogue gates U302, U800
•
Op amp U760
•
3.3V sub regulator Q910
4.6.2.3 3.3V Regulator U902/Q918
•
PLL Synthesiser IC U701
•
DSP U201
•
Flash memory U202
•
PLA U300
•
ADC CODEC U1, U820
4.6.2.4 2.5V Regulator U903
•
DSP U201
•
PLA U300
4.6.2.5 Negative Power Supply U904E/F
•
-16V output (-16V) for VCO Varicap tuning drivers
•
-12V Output (-12V) for Front end Varicap tuning drivers
4.6.2.6 Switched Battery
•
Transmit Power Amplifier
•
Speaker Amplifier
Summary of Contents for SRP 9100
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