[Hilo] When POK_IN should always connect to GND?


#1

[Hilo] In what condition POK_IN should always connect to GND?

Answer: If you plan to connect POK_IN (ignition signal of the module) always to GND you should consider:

  1. This will make the module immediately start when the power supply rise to 3.2Vmin.
  2. This will prevent the module to be switched off with the AT command AT*PSCPOF, otherwise the module will start again.
  3. The power supply must be used to switch the module on and off.
  4. A non-stabilized power supply must not be connected to the module VBAT inputs during its rise time.
  5. The power supply must rise and set to its final value (3.2Vmin) first before applying it to the module VBAT inputs. To do so, use “PowerGood” digital output on the power supply chipset, for example with Linear LT1913 to know when the voltage is stabilized, use also a MOS transistor to connect the power supply with the module input after the “PowerGood” is active.