LPWA Module Series
BG77 Hardware Design
BG77_Hardware_Design 30 / 76
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3.6. Power on and off Scenarios
3.6.1. Turn on Module Using the PWRKEY Pin
The following table shows the pin definition of PWRKEY.
Table 7: Pin Definition of PWRKEY
When BG77 is in power off mode, it can be turned on to normal mode by driving the PWRKEY pin to a low
level for a duration between 500ms and 1000ms. It is recommended to use an open drain/collector driver
to control the PWRKEY. A simple reference circuit is illustrated in the following figure.
Turn on pulse
PWRKEY
4.7K
47K
500ms~1000ms
10nF
Figure 5: Turn on the Module Using Driving Circuit
Another way to control the PWRKEY is using a button directly. When pressing the key, electrostatic strike
may generate from the finger. Therefore, a TVS component is indispensable to be placed nearby the
button for ESD protection. A reference circuit is shown in the following figure.
Pin Name Pin No. Description DC Characteristics Comment
PWRKEY 46
Turn on/off the
module
Vnorm=1.5V
V
IL
max=0.45V
The output voltage is 1.5V because
of the voltage drop inside the
Qualcomm chipset.
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