Quectel EC21 Series

LTE Standard Module Series
EC21_Series_Hardware_Design
35
/ 118
before startup.
If unused, keep it
open.
COEX_UART_
RX
137 DI
LTE/WLAN &
Bluetooth
coexistence
receive
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.2 V
V
IH
max = 2.0 V
1.8 V power domain.
Cannot be pulled up
before startup.
If unused, keep it
open.
COEX_UART_
TX
138 DO
LTE/WLAN &
Bluetooth
coexistence
transmit
V
OL
max = 0.45 V
V
OH
min = 1.35 V
1.8 V power domain.
Cannot be pulled up
before startup.
If unused, keep it
open.
WLAN_SLP_
CLK
118 DO WLAN sleep clock
If unused, keep it
open.
BT_RTS* 37 DI
DTE request to
send signal from
DCE
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.2 V
V
IH
max = 2.0 V
1.8 V power domain.
If unused, keep them
open.
BT_TXD* 38 DO
Bluetooth UART
transmit
V
OL
max = 0.45 V
V
OH
min = 1.35 V
BT_RXD* 39 DI
Bluetooth UART
receive
V
IL
min = -0.3 V
V
IL
max = 0.6 V
V
IH
min = 1.2 V
V
IH
max = 2.0 V
BT_CTS* 40 DO
DTE clear to send
signal from DCE
V
OL
max = 0.45 V
V
OH
min = 1.35 V
1.8 V power domain.
Cannot be pulled up
before startup.
If unused, keep it
open.
BT_EN* 139 DO
Bluetooth function
enable
V
OL
max = 0.45 V
V
OH
min = 1.35 V
1.8 V power domain.
If unused, keep it
open.
Antenna Interface
Pin Name Pin No. I/O Description DC Characteristics Comment
ANT_DIV 35 AI
Diversity antenna
interface
50 Ω impedance.
If unused, keep it
open.
ANT_MAIN 49 AIO
Main antenna
interface
50 Ω impedance.
ANT_GNSS 47 AI
GNSS antenna
interface
50 Ω impedance.
If unused, keep it