Product Info

LTE Standard Module Series
EG95 Series Hardware Design
EG95_Series_Hardware_Design
36 / 99
VBAT_BB
32, 33
Power supply for module’s
baseband part.
3.3
3.8
4.3
V
GND
3, 31, 48, 50,
54, 55, 58, 59,
61, 62, 67–74,
79–82, 89–91,
100–106
Ground
-
0
-
V
3.6.2. Decrease Voltage Drop
The power supply range of the module is from 3.3V to 4.3V. Please make sure that the input voltage will
never drop below 3.3V. The following figure shows the voltage drop during burst transmission in 2G
network. The voltage drop will be less in 3G and 4G networks.
Burst
Transmission
Burst
Transmission
VBAT
Min.3.3V
Drop
Ripple
Figure 7: Power Supply Limits during Burst Transmission
To decrease voltage drop, a bypass capacitor of about 100µF with low ESR (ESR = 0.7 Ω) should be used,
and a multi-layer ceramic chip (MLCC) capacitor array should also be reserved due to its ultra-low ESR. It
is recommended to use three ceramic capacitors (100 nF, 33 pF, 10 pF) for composing the MLCC array,
and place these capacitors close to VBAT_BB/VBAT_RF pins. 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_BB trace should be no less than 1 mm, and the width of VBAT_RF trace should be no
less than 2 mm. In principle, the longer the VBAT trace is, the wider it will be.
In addition, in order to avoid the damage caused by electric surge and electrostatics discharge (ESD), it is
suggested that a TVS diode with suggested low reverse stand-off voltage V
RWM
, low clamping voltage V
C
and high reverse peak pulse current I
PP
should be used. The following figure shows the star structure of
the power supply.