range of custom pcb

[karthikeyan]

Hi,

  My nrf 52840 pdk and my custom pcb with nrf 52840 soc. both are running with same application ble_proximity example from sdk 14.1 and softdevice s140 5.0. when i set the Tx_power to 4dbm. i am expecting the range of custom pcb should be equal to my pdk. but the range of custom pcb is very low when compared to pdk. how can i achieve the range of custom board equal to pdk?

thanks and regards,

karthikeyan

[FormerMember]

A typical mistake that leads to shorter range is wrong value of the load capacitors for the 32 MHz crystal. The value of the load capacitors should be calculated according to the formula in the "Crystal and load capacitors" section in this tutorial.

Wrong values of the load capacitors leads to an offset of the crystal frequency, and an offset of the carrier frequency.

Could you check if this is the problem on your board?

[karthikeyan]

hi kristin,

  after several reviews of custom pcb and BOM from the help of nordic team. 32 MHz crystal is 

ABM11-32.000MHZ-D2X-T3 CRYSTAL, 32MHZ, 10PF, 2 X 1.6MM

according to 10pf crystal. the load capacitor is choosed

15pf. so i dont think the load capacitor will be problem.

regards

karthikeyan

[FormerMember]

Okay, I see.

Could you upload the schematic and layout (gerber or altium) so that I can have a look at it? (If you don't want anybody else to see it, you can make the case private.)

[karthikeyan]

hi kristin,

    already there was a private question with the heading "custom board programming fails"  which i closed on last friday. there i have attached the gerber file and BOM. if you cant check it. i will upload gerber. but how can i make the case private?

thanks and regards,

karthikeyan

[karthikeyan]

hi kristin,

  any update?

regards,

karthikeyan