recommendation for power config nrf51822

[toashwin]

I am planning on using: NRGF51822 CDAB WCSP (= 128KB Flash, 16KB RAM, 3.5x3.5mm) Another main chip I will be using is: LSM303AGR (www.st.com/.../en.DM00177685.pdf)

Both of them can run at 1.8v

I plan to use "two" batteries in series of type: - Battery size 13. (1.4v.) www.hearingaidbatteryshop.com/.../duracell-13-data.pdf

Power management is very critical for! I dont want to be changing batteries for a year.

So what configuration should I be using nrf51822? Internal LDO setup? DC/DC Convertor setup? Low voltage setup with external regulator? - If so what is recommended regulator?

What setup do you for the NRF Beacon development board from Nordic?

Thanks Ashwin

[Øyvind Karlsen]

Hi,

For best power efficiency on the chip use DC/DC, the DC/DC should be switched on in times of high current draw (CPU activity, Radio TX/RX), as that is when it saves the most power.

As for the supply voltage that is up to you to evaluate. You need a battery that can support the inrush current from the chip entering TX mode (~15 mA @ 3V). If you want to use an external regulator that will add to your BoM, and the device might not be very efficient. You also need to ensure that it has a ripple below 100 mV pk-pk.

The nRF beacon kit uses 3V3 (from a CR2032 battery) with DC/DC configuration.

Best regards,

Øyvind