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high-temperature air and high-power heating devices as possible.
4.2
Avoid Power Leakage
When the module is not powered on, if there is data input at the input ports (including RXD
and GPIO), it will cause power leakage on the VCC. When the leakage voltage is higher
than 1.6 V, it may cause failure of starting up when the module is powered on.
Solution:
When the module is not powered on, make sure that the IO ports connected to the module
is in a high-resistance state or a low level to avoid power leakage. You can also connect
a 1KΩ resistor at the RX ports and a 33Ω or 1KΩ resistor at the TX ports, and connect a
4.7KΩ resistor at other necessary PIOs.
4.3
Power Supply Requirements
4.3.1
Main Supply (VCC)
The voltage range of VCC is 3.0 V ~ 3.6 V.
Notes:
The VCC initial level when power-on should be less than 0.4 V.
The VCC ramp when power-on should be monotonic, without plateaus.
The voltages of undershoot and ringing should be within 5% VCC.
VCC power-on waveform: The time interval from 10% rising to 90% must be within
100 μs ~ 10 ms.
Power-on time interval: The time interval between the power-off (VCC < 0.4 V) to
the next power-on is recommended to be larger than 500 ms.
4.3.2
Backup Supply (V_BCKP)
If the hot start function is needed, users should supply backup power to the module. The
voltage range of V_BCKP is 1.65 V ~ 3.6 V.
Notes:
The V_BCKP initial level when power-on should be less than 0.4 V.
The V_BCKP ramp when power-on should be monotonic, without plateaus.
The voltages of undershoot and ringing should be within 5% V_BCKP.
V_BCKP power-on waveform: The time interval from 10% rising to 90% must be
within 100 μs ~ 10 ms.