Hardware Guide

4 Circuit Design

4.1 Power Interface

4.1.1 Power input

A stable power supply ensures normal operation of the LC116-LA series module. During

design, ensure that the power supply ripple is lower than 300 mV (the circuit ESR is less

than 100 mΩ). When the module works in GSM mode (burst transmit), the maximum

working current can reach 3 A. Ensure that the power supply voltage is not lower than

3.3 V. Otherwise, the module may be powered off or restarted. When the module is

operating in burst transmit state, the power limit is as shown in the following figure.

Burst transmit Burst transmit

min:3.3V

Power supply

Ripple  300mV

Drop

VBAT  3.3V

Figure 4. Power supply limit

The ripple of the power supply should be lower than 300 mV, and the line ESR (equivalent

series resistance) should be <150 mΩ. When the module is working, it is necessary to

ensure that the voltage of the DC power supply is not lower than the minimum voltage.

The VBAT power supply of LC116-LA module requires star wiring to the power supply pins.

The following figure shows the recommended design of the power supply.