User's Manual

720 Hardware User Guide

Figure 2-6 Reference designs of separated power supply

Never use a diode to make the drop voltage between a higher input and module power.

Otherwise, Neoway will not provide warranty for product issues caused by this. In this situation,

the diode will obviously decrease the module performances, or result in unexpected restarts, due

to the forward voltage of diode will vary greatly in different temperature and current.

EMC Considerations for Power Supply

Place transient overvoltage protection components like TVS diode on power supply, to absorb

the power surges. SMAJ5.0A/C could be a choice.

2.3.2 VDDIO_1P8

VDDIO_1P8 supports output voltages of 1.8V. It is recommended that VDDIO_1.8V@100mAbe

used only for interface level shifting and to add ESD to protect while using.

2.3.3 ON/OFF

Power-On

After powering on the VBAT pin, you can use PWRKEY to start the module by inputting low-level

pulse for 100 ms (200 ms is recommended). This pin is pulled up by 200 internally. Its typical

high-level voltage is 1.8 V. The following circuit Figure 2-7 or Figure 2-8 is recommended to

control PWRKEY.