Turn On; Turn On With Pwpkey - Quectel EG915U Series Hardware Design

Figure 7: Power Supply Limits during Burst Transmission
To decrease the voltage drop, use bypass capacitors of about 100 µF with low ESR (ESR = 0.7 Ω) and
reserve a multi-layer ceramic chip (MLCC) capacitor array due to their 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 the VBAT_SENSE and VBAT_RF pins. When the external power supply is connected
to the module, VBAT_SENSE and VBAT_RF need to be routed in star structure. The width of the
VBAT_RF trace should not be less than 2.5 mm. When used as a power supply pin (that is, without
charging function), the width of the VBAT_SENSE trace should not be less than 1 mm. In principle, the
longer the VBAT trace is, the wider it will be.
In addition, to avoid the surge, use a TVS diode of which reverse working voltage is 4.7 V and peak pulse
power is up to 2550 W. The reference circuit is shown as below:
VBAT
+
D1 C1
100 µ F
WS4.5D3HV

3.5. Turn on

3.5.1. Turn on with PWPKEY

Table 7: Pin Definition of PWRKEY
Pin Name
PWRKEY
When the module is in power down mode, you can turn it on to normal mode by driving the PWRKEY pin
low for at least 2 s. It is recommended to use an open drain/collector driver to control the PWRKEY. A
EG915U_Series_Hardware_Design
C4
C2 C3
100 nF 10 pF
33 pF
Figure 8: Power Supply
Pin No. I/O
15 DI
+
C5 C6 C7
100 µ F 100 nF 33 pF 10 pF
Description
Turn on/off the module
LTE Standard Module Series
VBAT_RF
VBAT_BB
C8
Module
Comment
VBAT power domain.
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