RE: nrf51822 and nrf51422 with DC/DC avialability

tim — Mon, 28 Apr 2014 16:49:59 GMT

There is a typo in the DC/DC calculation nrf51822 LDO DC/DC Total 11mA ~2mA ~8mA 22mA 20mA ~4mA ~15mA 39mA

RE: nrf51822 and nrf51422 with DC/DC avialability

Stefan Birnir Sverrisson — Mon, 28 Apr 2014 07:10:49 GMT

Hi Tim

Our current recommendation on DC/DC is described here. However, we expect the nRF51 third revision hardware to have a functional DC/DC to use with the softdevices we offer. For further information you should contact your Nordic's sales representative.

Yes, you are correct that the CPU will consume 4.4mA when executing code from flash memory, and the radio consumes 7mA-16mA. However, this is not the actual current consumption because the CPU is usually not utilized 100% and the radio is most certainly not utilized 100%. For a typical BLE application, radio is utilized with around 1% and the CPU perhaps 2%-5%. When the radio is not utilized it does not consume anything, and when the CPU is not utilized, it is put into low power mode and consumes very little. Depending on the low power mode chosen, the chip consumes 0.6uA (System Off low power mode) or 2.6uA (System On low power mode), where the CPU is in low power state.

The current consumption greatly depends on your application. If you choose short connection interval, the chip will consume more power but then you will enable increased throughput and short latency. More on current consumption is described on this thread and this thread.