SLM770A Module Hardware Design Manual
MeiG Smart Technology Co., Ltd 77/77
The following figure is the module switch threshold state definition.
Figure 2 Switching machine threshold
The following figure shows the voltage drop during transmitting burst in 2G network. The voltage drop
will be less in 3G and 4G networks.
Figure 3 Power requirements for burst transmission
To reduce voltage sags, a 100uF filter capacitor with a low ESR is required. MLCC has the best ESR. It
is recommended to add 3 ceramic capacitors (100nF, 33pF, 10pF) to VBAT_BB and VBAT_RF pins, and
the capacitors should be placed close to the VBAT pins. At the same time, in order to ensure better
power supply performance, a TVS tube is added near the input end of the module VBAT to improve the
surge voltage bearing capacity of the module. It is recommended to use Changyuan Vian, model
WS4.5DPV. If the VBAT has high-frequency interference, it is recommended to add magnetic bead
filtering. The recommended magnetic bead model is BLM21PG300SM1D or MPZ2012S221A. When the
To Next Page