low voltage disconnects

[Rich]

I had a nRF81522 design that was working at 3.3V and I dropped the voltage to 1.9V. I didn't change anything else, but now I am getting periodic disconnects during interogation. My presumption is that I have some kind of brown out problem, but the board is very small with dedicated ground and power planes, so low impedance and the number of capacitors and their values seem to be equivalent to the evaluation kits.

I'll get a scope on the rails later today, but wondered if there other things that I should be looking at too?

Just as an example... you can't run internal DC-DC converter will a power supply of less than X... or you can only use a TX power of -4 if your voltage is below Y...

Thanks

[Dave_couling]

1.9V is too low for DCDC operation. For DCDC the minimum operating voltage as defined in the PS is 2.1V. You would need to have used the internal LDO hardware configuration to operate down to the 1.8V spec.

[MartinBL]

Just for the record, the latest Product Specification is V3.1 (but i guess that was what you meant) and can be found here.