Quectel EC21-AU - Page 30

LTE Standard Module Series
EC21_Series_Hardware_Design
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NET_STATUS 6 DO
Indicate the
module’s network
activity status
V
OH
min = 1.35 V
V
OL
max = 0.45 V
1.8 V power domain.
If unused, keep it
open.
USB Interface
Pin Name Pin No. I/O Description
DC
Characteristics
Comment
USB_VBUS 71 DI
USB connection
detect
Vmax = 5.25 V
Vmin = 3.0 V
Vnom = 5.0 V
USB_DP 69 AIO
USB differential
data (+)
USB 2.0 Compliant.
Require differential
impedance of 90 Ω.
If unused, keep them
open.
USB_DM 70 AIO
USB differential
data (-)
(U)SIM Interface
Pin Name Pin No. I/O Description
DC
Characteristics
Comment
USIM_GND 10
Specified ground for
(U)SIM card
USIM_
PRESENCE
13 DI
(U)SIM card
insertion detect
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 it
open.
USIM_VDD 14 PO
(U)SIM card power
supply
Iomax = 50 mA
1.8 V (U)SIM
：
Vmax = 1.9 V
Vmin = 1.7 V
3.0 V (U)SIM
：
Vmax = 3.05 V
Vmin = 2.7 V
Either 1.8 V or 3.0 V is
supported by the
module automatically.
USIM_DATA 15 DIO (U)SIM card data
1.8 V (U)SIM：
V
IL
max = 0.6 V
V
IH
min = 1.2 V
V
OL
max = 0.45 V
V
OH
min = 1.35 V
3.0 V (U)SIM：
V
IL
max = 1.0 V
V
IH
min = 1.95 V
V
OL
max = 0.45 V