LTE Standard Module Series
EC200U_Series_Hardware_Design 21 / 94
V
IH
max = 2.0 V
AUX_TXD
138
DO
Auxiliary UART
transmit
V
OL
max = 0.45 V
V
OH
min = 1.35 V
1.8 V power domain.
If unused, keep it
open.
ADC Interfaces
Pin Name
Pin No.
I/O
Description
DC Characteristics Comment
ADC2
43
AI
General-purpose
ADC interface
Voltage range:
0
–
VBAT_BB
Use 1
kΩ resistor in
series.
If unused, keep it
open.
The external resistor
should be less than
100
kΩ when the
voltage divider
resistor applies.
ADC1
44
AI
General-purpose
ADC interface
Voltage range:
0
–
VBAT_BB
ADC0
45
AI
General-purpose
ADC interface
Voltage range:
0
–
VBAT_BB
Analog Audio Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
LOUDSPK_P
73
AO
Loudspeaker
differential output
(+)
If unused, keep them
open.
LOUDSPK_N
74
AO
Loudspeaker
differential output (-)
MIC_P
75
AI
Microphone analog
input (+)
MIC_N
77
AI
Microphone analog
input (-)
I2C Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics Comment
I2C_SCL
41
OD
I2C serial clock
Require external
pull-up to 1.8 V if
used.
If unused, keep it
open.
I2C_SDA
42
OD
I2C serial data
I2C2_SCL
141
OD
I2C serial clock
I2C2_SDA
142
OD
I2C serial data
PCM Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
