Service Guide

LTE Standard Module Series

EG91_Series_Hardware_Design

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The power-up scenario is illustrated in the following figure.

≤ 0.5 V

= 0. 8 V

VBAT

PWRKEY

≥ 500 ms

RESET_N

STATUS

(DO)

I nactive

Active

UART

I nactive Active

USB

≥

≥ 12 s

≥ 13 s

VDD_EXT

BOOT_CONFIG &

USB_BOOT Pins

About 100 ms

10 s

NOTE 1

≥ 100 ms. After this time, the BOOT_CONFIG

pins can be set to high level by external circuit.

Figure 12: Power-up Timing

1. Make sure that VBAT is stable before pulling down PWRKEY pin. The time between them is no less

than 30 ms.

2. PWRKEY can be pulled down directly to GND with a recommended 10 kΩ resistor if the module

needs to be powered on automatically and shutdown is not needed.

3. BOOT_CONFIG pins (SPI_CLK, USB_BOOT, PCM_CLK, PCM_SYNC) cannot be pulled up

before startup.

3.7.2. Turn off Module

Either of the following methods can be used to turn off the module normally:

 Use the PWRKEY pin.

 Use AT+QPOWD.

NOTE