User's Manual

LTE Module Series
EC25Hardware Design
EC25_Hardware_DesignConfidential / Released 34 / 90
3.6.3. Reference Design for Power Supply
Power design for the module is very important, asthe performance of the module largely depends on the
power source. The power supply is capable of providing sufficient current up to 2A at least. If the voltage
drop between the input and output is not too high, it is suggested that you shoulduse an LDO to supply
power for the module. If there is a big voltage difference between the input source and the desired output
(VBAT), a buck converter is preferred to be used as thepower supply.
The following figure shows a reference design for +5V input power source. The typical output of the power
supplyis about 3.8V and the maximum load current is 3A.
Figure 9: Reference Circuit of Power Supply
In order to avoid damaging internal flash, please do not switch off the power supply when the module
works normally. Only after the module is shutdown by PWRKEY or AT command, the power supply can be
cut off.
3.6.4. Monitor the Power Supply
AT+CBC command can be used to monitor the VBAT_BB voltage value. For more details, please refer to
document [2].
3.7. Turn on and off Scenarios
3.7.1. Turn on Module Using the PWRKEY
The following table shows the pin definition of PWRKEY.
NOTE