EG91 Pulse in VDD_EXT line


I’ve developed a custom board with EG91 module. Most of boards starts and works correctly according to timing (figure 12 on pag 36 of EG91 Hardware Design). However, some boards does not start. Power is supplied to board but STATUS line is not activated. I see that VDD_EXT power line is on during 1 second aproximately and then is off. The same with VDD_SIM.

Some suggestion?



Could you please give me more information about it, such as schematic or any AT results?I guess it is the problem about power supply.