Product Info

Smart LTE Module Series
SC20 Hardware Design
SC20_Hardware_Design 36 / 130
1.
1)
GPIO_68 and GPIO_88 cannot be pulled up during start-up.
2.
2)
RESET_N is disabled by default and can be enabled through software configuration.
3.4. Power Supply
3.4.1. Power Supply Pins
SC20 provides two VBAT_RF pins and two VBAT_BB pins for connecting with an external power supply.
The VBAT_RF pins are used for the RF part of the module and the VBAT_BB pins are used for the
baseband part of the module.
3.4.2. Decrease Voltage Drop
The power supply range of the module is 3.5V~4.2V, and the recommended value is 3.8V. The power
supply performance, such as load capacity, voltage ripple, etc. directly influences the module’s
performance and stability. Under ultimate conditions, the transient peak current of the module may surge
up to 3A. If the supply voltage is not enough, there will be voltage drops, and if the voltage drops below
3.1V, the module will be turned off automatically. Therefore, please make sure the input voltage will never
drop below 3.1V.
3.1V
Voltage
3.8V
3A
Input current
Figure 3: Voltage Drop Sample
To decrease voltage drop, a bypass capacitor of about 100µF with low ESR (ESR=0.7Ω) should be used,
and a multi-layer ceramic chip capacitor (MLCC) should also be reserved due to its ultra-low ESR. It is
recommended to use three ceramic capacitors (100nF, 33pF, 10pF) for composing the MLCC array, and
place these capacitors close to VBAT_BB/RF pins. The main power supply from an external application
NOTES