Technical Manual

3. ELECTRICAL DESCRIPTION
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LZT 123 7607 R1B
Audio signal descriptions are listed below:
MICP and MICN are balanced differential microphone input signals.
These inputs are compatible with an electret microphone.
BEARP and BEARN are the speaker output signals. These are
differential-mode outputs. The electrical characteristics are given in the
table below.
The following table shows the ear piece impedances that can be connected
to BEARP and BEARN.
Pin Signal Dir Description
1 MICN I Microphone negative input
2 BEARN O Earpiece negative output
3 BEARP O Earpiece positive output
4 MICP I Microphone positive input
Parameter Limit
Output level (differential) ≥ 4.0 V
SS
Output level (dynamic load = 32 Ω) ≥ 2.8 V
SS
Distortion at 1 kHz and maximum output level ≤ 5 %
Offset, BEARP to BEARN ± 30 mV
Ear piece mute switch attenuation ≥ 40 dB
Ear piece model Impedance Tolerance
Dynamic ear piece [32 Ω + 800 µH] // 100 pF ± 20 %
Dynamic ear piece [150 Ω + 800 µH] // 100 pF ± 20 %
Piezo ear piece 1 kΩ + 60 nF ± 20 %