User's Manual

GL865-DUAL/QUAD V3 Hardware User Guide
1vv0301018 Rev.7 – 2013-10-30
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 43 of 78
Mod. 0805 2011-07 Rev.2
TIP: Since the J-FET transistor inside the microphone acts as RF-detector-amplifier, ask
vendor for a microphone with anti-EMI capacitor (usually a 33pF or a 10pF capacitor placed
across the output terminals inside the case).
10.2. LINE-IN connection
1u
220n
220n
1K
1K
1u
1u
AF_IN+
MIC/AF_IN+
MIC/AF_IN
-
AGND
MODULE
-
+
INPUT
ADC
Vmic
AF_IN
-
1u
220n
220n
1K
1K
MIC/AF_IN+
MIC/AF_IN-
AGND
MODULE
-
+
INPUT ADC
Vmic
Wire Or Ground Plane