User Guide

RH-21 Company Confidential
System Module Nokia Customer Care
Page 16  2004 Nokia Corporation. Issue 2 07/2004
Figure 6: Accessory Detection / External Audio.
Technical Information
ESD protection is made by spark gaps, buried capacitor and inside UEM, which is pro-
tected ±8 kV. RF and BB noise is prevented by inductors.
Charger IF
Introduction
The charger connection is implemented through the bottom connector. DCT-4 bottom
connector supports charging with both plug chargers and desktop stand chargers.
There are three signals for charging. Charger gnd pin is used for both desktop and for
plug chargers as well as charger voltage. PWM control line, which is needed for 3-wire
chargers, is connected directly to gnd in module PWB so the engine doesn't provide any
PWM control to chargers. Charging controlling is done inside UEM by switching UEM
internal charger switch on/off.
Interface
The fuse F100 protects the phone from currents that are too high (for example, when
broken or pirate chargers are used). L100 protects engine from RF noise, which may
occur in charging cable. V100 also protects the UEM asic from reverse polarity charging
voltage and from excessive charging voltage. C105 is also used for ESD and EMC protec-
tion. Spark gaps are used for ESD protection right after the charger plug.
2k2
Hookint
Headint Headint
EAD
MIC1&3 Bias
MIC1P
MIC1N
33N
HFCM
HF
UEM
2.1V
2.7V
/MBUS
1.8V
0.3V
0.8V
3...25k