Motorola P8190 Service Manual download pdf (Page 92)

Motorola Confidential Proprietary

TDMA Timeport™ P8190General Description

80

Analog/Digital Switch

The switching circuits are used to define the

proper PA loads when in analog mode or digi-

tal mode.

When a high PA supply voltage is present,

the PA may begin dissipating more heat. This

may cause overheating to the Call

Processor(U1000). To protect the U1000

from overheating, power is reduced by

switching loads.

Analog/Digital Switch

DCI (U1800)

The DCI(U1800) is the data converter inter-

face between the DSP and the RF functions

of a TDMA transceiver. It incorporates the

following functions:

 Dual channel forward data I and Q(RX_I

& RX_Q)

 Two DACs for reverse data I and Q(TX_I

& tx_Q)

 DAC for AFC

 DAC for AGC & DAC for reverse PA con-

trol

 DAC for PA bias

 Serial Synchronous Interface(SSI)

 Serial Peripheral Interface(SPI)

 Countdown timer for call processor wake-

up

 Free-running Real Time Counter to keep

track of the time when control processor is

stopped

 Internally generates clocks from single

master input

 Power saving power-down modes

 Analog wide band forward data signalling

functions with SPI interface

 Analog modulator interface

 Analog discriminator interfaces

 RF Discontinuous Receive during Manches-

ter decoding

 On chip voltage reference for transmit I

and Q

GCAP2 (U1500)

The GCAP2(U1500) provides the regulators

and start-up functions for the entire radio.

The GCAP2 contains the following hardware

blocks:

 On/Off control signals to properly activate

the radio.

 Bandgap reference voltage

 Audio amplification for the speaker

 Audio amplification for the alert

 Audio amplification for the EXT speaker

 Audio amplification of the microphone

 Audio CODEC

 Op-amps for use in the battery charger

 Internal D/A for the battery charger

 8 channel, 8 bit A/D

 Real Time Clock

 Linear regulators

- RX_2.75V for RX circuits

- 2.75V for logic circuits

- TX_2.75V for TX circuits

- 5V for negative regulator

- REF_2.75V for negative regulator

reference

 3 wire bus A/D

 Battery selection control circuitry

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