nRF51822 unprogrammed power consumption

[barry.haworth]

We are developing a new BLE tag product using the nRF51822. We would like to assemble the PCB and battery in a single operation then program the product sometime later. Can anybody please advise what the unprogrammed power consumption is of the nRF51822 configured in DC2DC converter buck mode? Our concern is that the unprogrammed nRF51822 will flatten the battery. Many thanks!

[John]

I am unable to answer your question regarding the power consumption of a unprogrammed part. Hopefully someone can provide an answer as I would be a bit nervous determining that number by experimentation.

That said, a potential solution to avoid needing to know this is to purchase your parts pre-programmed through a distributor that supports pre-programmed parts. It doesn't need to be programmed with your shipping code, just a simple set of code that puts the device into its lowest power state. You can reprogram it later in your production process to get your latest code on the device.

[Michael Dietz]

When the system enters ON mode it will, by default, reside in the low power sub mode. So worst case the chip should draw 2.6 uA (according to the product spec). Best case the chip is in System OFF mode and it's drawing .6 uA.

The buck converter will only kick in when the RADIO is active if you have it enabled.

My guess is that the chip is in System OFF mode until you program it (entering Debug Interface mode will turn it ON).

[barry.haworth]

Thanks John and Michael for your feedback. Very helpful indeed, we will investigate Michael's expectations of the current and take it from there.

Once again, thanks guys