User Guide

Power amplifier

The power amplifier, also called boomer, is a differential operational amplifier (opamp). It has a gain of +12 dB.

The differential output drives the internal handsfree speaker, IHF. The outputs go into a high impedance state

when powered down. The amplifier can be enabled and shut down using a GENIO line from Tiku. The boomer

is off when the shutdown pin (GENIO23) is low.

Software controls IHF, headset and earpiece volume via UEMEK. The output sound pressure level of the IHF is

controlled by software (Cbus is used for controlling).

The supply voltage for the IHF amplifier is taken directly from the battery voltage.

Mono/stereo implementation

The Digital Music Player is routed in stereo to bluetooth headset and in mono to other devices. FM Radio is

implemented only in mono.

Connections

Bluetooth

The Bluetooth solution is a single chip solution. The baseband interface to the bluetooth has a separate PCMbus

for audio giving in total 11 connections;

• 4 pins used for UART (data)

• 4 pins for PCM audio and

• 3 pins for control (Host wake-up, BT wake up and BT reset).

Bluetooth connects to TikuEDGE on the GENIO and GPIO busses.

The Bluetooth module is provided with power from an external LDO (Low drop out) regulator. This is enabled

by PURX, which is an internal UEMEK reset signal. This signal is high whenever the phone is powered on.

RM-13/33

Nokia Customer Care System Module Description

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