LTE Standard Module Series
V
IL
0.5V
VBAT
PWRKEY
500 ms
RESET_N
NOTE 1
VDD_EXT
About 5 ms
USB_BOOT
USB_BOOT can be pulled up to 1.8 V before
VDD_EXT is powered up, and the module will enter
emergency download mode when it is powered on.
About 22 ms
Figure 18: Timing Sequence for Entering Emergency Download Mode
.
4.3. (U)SIM Interface
The (U)SIM interface circuitry meets ETSI and IMT-2000 requirements. Both 1.8 V and 3.0 V (U)SIM
cards are supported.
Table 14: Pin Definition of (U)SIM Interface
1. Please make sure that VBAT is stable before pulling down PWRKEY pin. It is recommended that the
time between powering up VBAT and pulling down PWRKEY pin is no less than 30 ms.
2. When using MCU to control module to enter the emergency download mode, please follow the
above timing sequence. It is not recommended to pull up FORCE_USB_BOOT to 1.8 V before
powering up VBAT. Directly connect the test points as shown in
can manually force the
module into download mode.
3. USB_BOOT cannot be pulled up before startup.
Pin Name
Pin No.
I/O
Description
Comment
USIM_VDD
14
PO
(U)SIM card power supply
Either 1.8 V or 3.0 V
NOTE