Huawei MG323 manual Power-On and Power-Off Time Sequence, Vcoin Interface, VIO Interface

HUAWEI MG323 GSM M2M Module
Hardware Guide	Description of the Application Interfaces

3.3.3VCOIN Interface

VCOIN is an interface for standby power input of the RTC in the MG323 module. If the VBAT interface is ready for power supply, it on priority supplies the RTC with power. If the VBAT interface is not ready, the VCOIN interface provides standby power input for the RTC. In this case, the MG323 module needs 5 µA to maintain the RTC function.

You can use an external battery to supply power through the VCOIN interface. The recommended voltage is 3 V. You can also use an external capacitor if you do not use a battery. The capacitance determines the duration of the RTC when the VBAT interface is not ready.

The MG323 module supports charging external standby batteries. When the VBAT voltage is 3.8 V, the charging current is about 0.6 mA (typical value). Figure 3-3shows two types of circuits for your reference.

Figure 3-3VCOIN interface circuit

3.3.4VIO Interface

Through the VIO interface, the MG323 module can supply 2.8 V power externally with an output current of 10 mA (typical value) for external level conversion or other applications.

If the MG323 module is in sleep mode, the VIO interface is in the low power consumption state (< 500 µA). If the MG323 module is in power down mode, the VIO is in the disabled state. If VIO pin is not in use, disconnect the pin and make sure it is not grounded.

3.4 Power-On and Power-Off Time Sequence

3.4.1Overview

The power-on, power-off, and reset control parts of the B2B interface of the MG323 module includes power-on/power-off interface signal (TERM_ON) and the hardware reset interface signal (RESET). Table 3-3lists the definitions of the interface pins.

Issue 06 (2013-06-13)	Huawei Proprietary and Confidential	18
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