Power Supply; Power Supply Pins; Voltage Stability Requirements - Quectel SC200E Series Manual

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Smart Module Series

3.4. Power Supply

The module provides four VBAT pins for connection with external power supply.

The power supply range of the module is 3.5–4.4 V, and the recommended value is 3.8 V. The power

supply performance, such as load capacity, voltage ripple, etc. will directly influences the module's

performance and stability. Under ultimate conditions, the transient peak current of the module may surge

up to 3 A. If the power supply capacity is not sufficient, there will be the risk that the voltage drops below

3.4 V and as a result the module powers off automatically. Therefore, make sure the input voltage never

drops below 3.4 V.

3 A

Input current

3.8 V

Voltage

Figure 3: Voltage Drop Sample

To decrease voltage drop, use a bypass capacitor of about 100 µF with low ESR (ESR ≤ 0.7 Ω), and

reserve a multi-layer ceramic chip capacitor (MLCC) array due to its ultra-low ESR. It is recommended to

use three ceramic capacitors (100 nF, 33 pF, 10 pF) to compose the MLCC array and place these

capacitors close to VBAT pins. Additionally, add a 4.7 µF capacitor in parallel. The main power supply

from an external application has to be a single voltage source and can be expanded to two sub paths

with star structure. The width of VBAT trace should be no less than 3 mm. In principle, the longer the

VBAT trace is, the wider it should be.

In addition, to guarantee the stability of the power source, please use a TVS and place it as close to the

VBAT pins as possible to enhance surge protection. The following figure shows the star configuration of

the power supply.

SC200E_Series_Hardware_Design

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