VDD drops.

[Shimon_nohayo]

Hi,

I'm using nRF52832-CIAA.

VDD,Pin A7,  tide with Cap 4.7uF 0603

VDD Pin H7 tide with Cap 100nF 0201 

DEC3 100pF 0201

DEC2 100pF 0201

DEC4 1uF 0402

Using LDO 

VDD = 3V

When the device start advertising the VDD drops to 2.6 V  for the advertising duration and then returns to 3V.

Please advise if this is normal?

Shimon

[hmolesworth]

I recommend 150uF on VDD, typically by using 3 x 0603 connected in parallel. Less may work, it depends on your application and how close you want to operate the coin cell to it's end-of-life where the coin cell impedance is significantly higher (several k Ohm). This app note from TI might help: swra349.pdf

[Shimon_nohayo]

Thanks I will try it and check it