Vcoin Interface; Vio Interface - Huawei MG323 Hardware Manual

Gsm m2m module

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HUAWEI MG323 GSM M2M Module

Hardware Guide

3.3.3 VCOIN 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 3-2

shows two types of circuits for your reference.

Figure 3-2 VCOIN interface circuit

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.

Issue 04 (2011-08-22)

For detailed information about power supply design and printed circuit board (PCB) design,

see

HUAWEI MI Module Power Management Design

Management Design Guide

Huawei Proprietary and Confidential

Description of the Application Interfaces

Guide,

and

HUAWEI LGA Module PCB Routing Design Guide.

HUAWEI M2M Module Power

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