Product Info

Smart LTE Module Series
SC66 Hardware Design
SC66_Hardware_Design 85 / 139
 The module offers three audio input channels, including one differential input pair and two
single-ended channels. The three sets of MICs are integrated with internal bias voltage.
 The output voltage range of MIC_BIAS is programmable between 1.6V and 2.9V, and the maximum
output current is 3mA.
 The earpiece interface uses differential output.
 The loudspeaker interface uses differential output as well. The output channel is available with a
Class-D amplifier whose maximum output power is 1.5W when the load is 8Ω.
 The headphone interface features stereo left and right channel output, and headphone insertion
detection function is supported.
3.22.1. Reference Circuit Design for Microphone Interface
MIC1_P
ECM-
Type
R2
R1
Module
D1
MIC1_N
33pF
0R
0R
R3
0R
Figure 30: Reference Circuit Design for Analog ECM-type Microphone
EAR_P 53 AO Earpiece output (+)
EAR_M 52 AO Earpiece output (-)
SPK_P 55 AO Speaker output (+)
SPK_M 54 AO Speaker output (-)
HPH_R 51 AO Headphone right channel output
HPH_REF 50 AI Headphone reference ground
It should be connected
to main GND
HPH_L 49 AO Headphone left channel output
HS_DET 48 AI Headset insertion detection High level by default.