abhowmick22
Newbie level 1
Hi,I am using sim548z module and have made the circuit according to the hardware design guide that came along with the product.To test it,i am using a bench power supply instead of VBAT with 5A max. To get the voltages for vrtc and gps_vcc,I have used following LDOs
TPS7A4501KTTR pdf, TPS7A4501KTTR description, TPS7A4501KTTR datasheets, TPS7A4501KTTR view ::: ALLDATASHEET :::
TPS72218DBVT pdf, TPS72218DBVT description, TPS72218DBVT datasheets, TPS72218DBVT view ::: ALLDATASHEET :::
The problem is the circuit wont start up(ie netlight wont blink as expected) when i pull pwrkey to ground for a sec.However,netlight led blinks at interval of 1 sec as long as pwrkey is held low.I am just using a wire for pwrkey which is left NC generally and pulled low to trigger the module.Also i tried using a 2200uf cap at out of power supply to reduce spikes.I monitored the SIM_VDD pin as well and it shows 0V instead of 1V/3V.Do I need to do something for this or the module automatically detects sim power type?
Thanx for your ideas...
TPS7A4501KTTR pdf, TPS7A4501KTTR description, TPS7A4501KTTR datasheets, TPS7A4501KTTR view ::: ALLDATASHEET :::
TPS72218DBVT pdf, TPS72218DBVT description, TPS72218DBVT datasheets, TPS72218DBVT view ::: ALLDATASHEET :::
The problem is the circuit wont start up(ie netlight wont blink as expected) when i pull pwrkey to ground for a sec.However,netlight led blinks at interval of 1 sec as long as pwrkey is held low.I am just using a wire for pwrkey which is left NC generally and pulled low to trigger the module.Also i tried using a 2200uf cap at out of power supply to reduce spikes.I monitored the SIM_VDD pin as well and it shows 0V instead of 1V/3V.Do I need to do something for this or the module automatically detects sim power type?
Thanx for your ideas...