External Audio Connections; Analog Audio Accessory Detection; Figure 13: Combined Headset And System Connector Audio Signal - Nokia NSB-5 Series Technical Documentation Manual

NSB-5
System Module

External Audio Connections

The external audio connections are presented in figure 16. A headset can be connected
directly to the system connector. The headset microphone bias is supplied from COBBA
AUXOUT output and fed to microphone through XMIC line. The 330ohm resistor from
SGND line to AGNDprovides a return path for the bias current.
Baseband
HOOKDET
MAD
HEADDET
100n
CCONT
EAD
AGND
10m
H
F
COBBA–
GJP
10k
AUX-
OUT
PD2
HFC
AGND
M
100n
MIC1
N
100n
MIC1
P
100n
MIC3
N
100n
MIC3
P

Figure 13: Combined headset and system connector audio signal

Analog Audio Accessory Detection

In XEAR signal there is a 47 kΩ pullup in the transceiver and 6.8 kΩ pull–down to SGND
in accessory. The XEAR is pulled down when an accessory is connected, and pulled up
when disconnected. The XEAR is connected to the HookDet line (in MAD), an interrupt is
given due to both connection and disconnection. There is filtering between XEAR and
HookDet to prevent audio signal giving unwanted interrupts.
Page 32
220k
100n
220k
VBB VBB
AGND
2k2 47k
27p
2k2
10u 1u
AGND
2k2
2k2
27p
27p
AGND AGND AGND
Nokia Mobile Phones Ltd.
PAMS Technical Documentation
VBB
47k
PC–Board
R01
SW01
47R
XEAR
LGN
D
33R
100MHz
AGND
100R XMI
C
100R
SGN
D
330R
R01= 100R
C01=33uF
C02=1000pF
C03=22pF
L01=MMZ2012Y6
01BT/TDK
+
+
C01
+
C03
C02
L01
Z01
Issue 1 03/01