NB-IoT Module Series
BC66 Hardware Design
BC66_Hardware_Design 20 / 50
When the timer T3412 times out, the module will exit from PSM automatically.
The module can also be woken up from PSM by PWRKEY or PSM_EINT*.
“*” means under development.
3.6. Power Supply
3.6.1. Power Supply Pins
BC66 provides two VBAT pins for connection with an external power supply. The table below describes
the module's VBAT and ground pins.
Table 6: Power Supply Pins
Pin Name
Pin No.
Description
Min.
Typ.
Max.
Unit
VBAT_BB
42
Power supply for the
module
’s baseband
part
2.1
3.3
3.63
V
VBAT_RF
43
Power supply for the
module
’s RF part
2.1
3.3
3.63
V
GND
1, 27, 34,
36, 37, 40, 41
GND
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 range of the module is 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 0402 package, and 22pF 0402 package) 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. A reference circuit is illustrated in the following figure. In
principle, the longer the VBAT trace is, the wider it will be.
NOTE
