Reference Design For Power Supply; Power Up/Power Down Scenarios; Turn On - Quectel BC66 Hardware Design

3.6.2. Reference Design for Power Supply

Power design for a module is critical to its performance. It is recommended to use a low quiescent current
LDO with output current capacity of 0.5A as the power supply for BC66. A Li-MnO2/2S alkaline battery
can also be used as the power supply. The supply voltage of the module ranges from 2.1V to 3.63V.
When the module is working, please make sure its input voltage will never drop below 2.1V; otherwise the
module will be abnormal.
For better power performance, it is recommended to place a 100uF tantalum capacitor with low ESR
(ESR=0.7Ω) and three ceramic capacitors (100nF, 100pF and 22pF) near the VBAT pins. Also, it is
recommended to add a TVS diode on the VBAT trace (near VBAT pins) to improve surge voltage
withstand capability. In principle, the longer the VBAT trace is, the wider it should be. A reference circuit
for power supply is illustrated in the following figure.

3.7. Power up/Power down Scenarios

3.7.1. Turn on

BC66 will be powered up after driving the PWRKEY pin to a low level voltage for at least 500ms.
Table 7: PWRKEY Pin
Pin Name Pin No.
PWRKEY 7
BC66_Hardware_Design
VBAT
+
C1 C2
D1
TVS
100uF 100nF 100pF
GND
Figure 5: Reference Circuit for Power Supply
Description
Pull down PWRKEY to power
up the module
Module
VBAT_RF
VBAT_BB
C3 C4
22pF
0402 0402
GND
PWRKEY Pull-down Time
≥500ms
NB-IoT Module Series
BC66 Hardware Design
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