User Guide

RH-23 Company confidential

System Module and User Interface CCS Technical Documentation

Page 36 Nokia Corporation. Issue 1 02/2004

Internal Audio

Internal Speaker

The internal earpiece is a dynamic earpiece with impedance of 32 ohms. The earpiece is

low impedance one since the sound pressure is to be generated using current and not

voltage as the supply voltage is restricted to 2.7V. The earpiece is driven directly by the

UEM and the earpiece driver (EARP & EARN outputs) is a fully differential bridge ampli-

fier with 6 dB gain. In RH-23, 8mm leak tolerant PICO earpiece is used.

Figure 18: Speaker connection

Table 34:

Internal Speaker signals

Signal Min Nom Max Condition Note

EARP 0.75V 0.8V 2.0Vpp

0.85V

Differential output

(Vdiff = 4.0Vpp)

EARN 0.75V 0.8V 2.0Vpp

0.85V