Reference Design For Power Supply - Quectel EG060K Series Hardware Design

To decrease voltage drop, at least one bypass capacitor of about 100 µF with low ESR and one multi-
layer ceramic chip (MLCC) capacitor array for its ultra-low ESR should be used for VBAT_BB/RF. It is
recommended to adopt ceramic capacitors for composing the MLCC array, and place these capacitors
close to VBAT pins. The main power supply from an external application must be a single voltage source
which can supply power along two sub paths with star structure. The trace of VBAT_BB should not be
wider than 1 mm, and the trace of VBAT_RF should not be wider than 2 mm. In principle, the longer the
VBAT trace is, the wider it should be.
In addition, for stable power supply, it is necessary to add a high-power TVS near VBAT_BB and
VBAT_RF. The star structure of the power supply is shown below.
VBAT
R1
0R
R2
0R
D1
TVS

3.2.2. Reference Design for Power Supply

The power design for the module is vital as the performance of the module largely relies on the power
source. The power supply of the module should be able to provide sufficient current up to 2 A at least. If
the voltage drop between the input and output is not too high, powering the module with an LDO is
recommended. If a big voltage difference exists between the input source and the desired output (VBAT),
a buck DC-DC converter is preferred.
The following figure shows a reference design for +5 V input power source. In this design, the typical
power supply output is about 3.8 V and the maximum load current is 3 A.
EG060K &EG120K _Series_Hardware_Design
103
C1
C2 C3
100 μF
100 nF 6.8 nF
C6
C7 C8
100 μF
100 nF 220 pF
Figure 9: Star Structure of the Power Supply
C4 C5
220 pF 68 pF
C10 C11
C9 C12
68 pF 15 pF 9.1 pF
LTE-A Module Series
VBAT_BB
VBAT_RF
Module
4.7 pF
35 /