SIM300 module extreme low power consumption?

[user0n9]

I bought few pieces of SIM300 recently..

after i attached the SIM300 to a self design board and without switching on the SIM300,
the drain current of the board is 16mA
after switch on SIM300 in full functionality mode (CFUN=1) the Drain current is around 23.86mA
when in minimum functionality mode (CFUN=0) the Drain current is consider fixed at 23.86mA
when no RF circuit mode (CFUN=4) the Drain current is consider fixed at 23.92mA
and in sleep mode the Drain current is 18.45mA

so we can see that sleep mode takes around 2.45mA which is correct and almost same as stated in Manual
but why CFUN 0, 1, 4 drain current does not have not much different?
as what i read.. CFUN 0 should have the lowest current consumption compare to CFUN 2 and CFUN 4.
can you help me with this please?

p/s: the board is functioning as expected (no problem at all for voice call, sms, gprs and so on)

thanks in advance
Pierre

 

[user0n9]

greeting,
actually will SIM300 drain current goes lower when it is set from CFUN=1 to CFUN=0?

what i thinking is, the purpose of CFUN=0 is to limit the value of current drain instead of lower it.
because the RF function and SIM card function will be closed, in this case all AT commands need RF function or SIM card function will not accessible.
so it is impossible to drain more current while both function is closed.
correct me if i am wrong.

thanks
Pierre