NB-IoT Module Series
BC66 Hardware Design
BC66_Hardware_Design 22 / 57
It is recommended 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
Figure 6: 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.
PWRKEY
S1
Close to S1
TVS
Figure 7: Turn on the Module Using Keystroke
The power up timing is illustrated in the following figure.
PWRKEY
VDD_EXT
42ms
≥500ms
VBAT
Module
Status
OFF
RUNNING
BOOTING
Figure 8: Power up Timing